Hi all,

I don't know if this is the correct place to ask. Feel free to point me
to an other NG if this is off-topic here.

On the 27th of November, there is "de dag van de wetenschap" (the day of
science) here in Belgium, and I am helping out a local fablab on this event.

This event is aimed at kids between 14 and 18. I help out in the
"electronics corner"

We are working on a setup where we want to show all kind of electronic
sensors. To link electronics with science, The idea is to provide the
visitor with a description of the internal working of a sensor, and let
them find the correct sensor in the batch.

So I am looking for information on the internal working of different
kind of sensors.
For certain sensors, it is well known (hall-sensor, light-sensor, ... )
and in certain cases it is described in the datasheets (laser-based
CO2-sensor or fine-particle dust-sensor).

But I am looking for information on the following sensors / devices:
- temperature sensors
- air humidity
- gas (CO, VOC) that are not based on lasers
- hardware based gyroscopes

Thanks!

Cheerio! Kr. Bonne,

On a sunny day (Thu, 27 Oct 2022 08:30:14 +0200) it happened kristoff
<kristoff@skypro.be> wrote in <tjd8hm$2mt7c$1@dont-email.me>:

>Hi all,
>
>
>I don't know if this is the correct place to ask. Feel free to point me
>to an other NG if this is off-topic here.
>
>
>
>On the 27th of November, there is "de dag van de wetenschap" (the day of
>science) here in Belgium, and I am helping out a local fablab on this event.
>
>This event is aimed at kids between 14 and 18. I help out in the
>"electronics corner"
>
>
>We are working on a setup where we want to show all kind of electronic
>sensors. To link electronics with science, The idea is to provide the
>visitor with a description of the internal working of a sensor, and let
>them find the correct sensor in the batch.
>
>
>
>So I am looking for information on the internal working of different
>kind of sensors.
>For certain sensors, it is well known (hall-sensor, light-sensor, ... )
>and in certain cases it is described in the datasheets (laser-based
>CO2-sensor or fine-particle dust-sensor).
>
>But I am looking for information on the following sensors / devices:
>- temperature sensors
>- air humidity
>- gas (CO, VOC) that are not based on lasers
>- hardware based gyroscopes

Did you try google <sensor type wikipedia> ?

Jan,

Op 27.10.22 om 09:00 schreef Jan Panteltje:
>> But I am looking for information on the following sensors / devices:
>> - temperature sensors
>> - air humidity
>> - gas (CO, VOC) that are not based on lasers
>> - hardware based gyroscopes
>
> Did you try google <sensor type wikipedia> ?

Wait .. do you still use google?

I am old enough to know about "netiquette". Yes, I did do my homework
before posting :-)

As said, for certain sensors, the datasheets do give me enough info to
write a text for the 14-to-18 year audience.

But take -say- a BME280/BMP280, the only thing I can make out from the
datasheet is that pressure is messured by a piezzo-electric element.
For temperature and humidy, no info.

For the gyroscopes, I am wondering if they really messure the angular
motion, or that they message lineair-motion in the x-y-z axis and then
calculate angular motion based on that.

Cheeri0! Kr. Bonne.

On a sunny day (Thu, 27 Oct 2022 09:33:35 +0200) it happened kristoff
<kristoff@skypro.be> wrote in <tjdc8f$2nc2l$1@dont-email.me>:

>Jan,
>
>
>Op 27.10.22 om 09:00 schreef Jan Panteltje:
>>> But I am looking for information on the following sensors / devices:
>>> - temperature sensors
>>> - air humidity
>>> - gas (CO, VOC) that are not based on lasers
>>> - hardware based gyroscopes
>>
>> Did you try google <sensor type wikipedia> ?
>
>Wait .. do you still use google?

Google is one of the most valuable things we have for [self]education.
Of course it only works if you are interested.
Combined ith wikipedia it replaces that many "Winkler Prins" I think it was
encecopedia books on your hobby sheleves ;-)

>I am old enough to know about "netiquette". Yes, I did do my homework
>before posting :-)

>As said, for certain sensors, the datasheets do give me enough info to
>write a text for the 14-to-18 year audience.

Well I do not know much about evolution of the recent humming beans species
but when I was about ten years old I was reading 'Zo werkt de Televisie" and
"Zo werkt de radio" from Van Aisberg (you are from Begium? should know that name).
In those books he has somebody (Vraagal" asking the right questions
for who he then gives the right aswers.
Asking the right question is a very important thing.
Somebody here constantly askes the wrong ones and I gave up on educating that person.
At 14 I was designing tube amps for the school band, radio transmiters, what not
So it all depends on the student's interest and the teacher.

>But take -say- a BME280/BMP280, the only thing I can make out from the
>datasheet is that pressure is messured by a piezzo-electric element.
>For temperature and humidy, no info.

Mesuring temperature is usualy easy, almost any conductor is temperature sensitive,
if it is a chip then chances are it is a silly-con and perhaps uses a diode junction that has, what was it? -2 mV / degree C
or so temp coefficient, diodes make perfect temperature sensors, used those in big projects.

So google solid state humidity sensors?
https://en.wikipedia.org/wiki/Hygrometer
pick your choice.
maybe that datasheet mentions one of those methods in the first few lines?
coud well be resistive or capacitive?

>For the gyroscopes, I am wondering if they really messure the angular
>motion, or that they message lineair-motion in the x-y-z axis and then
>calculate angular motion based on that.

You did say 'hardware gyroscope' that leaves only this:
https://en.wikipedia.org/wiki/Gyroscope

But if you are talking about MEMS sensors, like your [possibly smart]phone has (at least my Xiaomi has)
https://en.wikipedia.org/wiki/Accelerometer

etc etc

;-)
fun

On 10/26/2022 11:30 PM, kristoff wrote:
> On the 27th of November, there is "de dag van de wetenschap" (the day of
> science) here in Belgium, and I am helping out a local fablab on this event.
>
> This event is aimed at kids between 14 and 18. I help out in the "electronics
> corner"
>
> We are working on a setup where we want to show all kind of electronic sensors.
> To link electronics with science, The idea is to provide the visitor with a
> description of the internal working of a sensor, and let them find the correct
> sensor in the batch.

That may be hard -- unless you deliberately "load the deck" in favor of
such discoveries because the "internals" of many aren't readily apparent.

For example, a Hall Effect sensor can physically look like a temperature sensor
(depending on the technology being used) with the only difference being the
actual part numbers on the devices.

> So I am looking for information on the internal working of different kind of
> sensors.
> For certain sensors, it is well known (hall-sensor, light-sensor, ... ) and in
> certain cases it is described in the datasheets (laser-based CO2-sensor or
> fine-particle dust-sensor).
>
> But I am looking for information on the following sensors / devices:
> - temperature sensors
> - air humidity
> - gas (CO, VOC) that are not based on lasers
> - hardware based gyroscopes

If you only want the participants to *visually* examine the devices to
ascertain their intent, perhaps you might want to pick a different
set of sensors and technologies?

E.g., an LVDT can typically be recognized as sensing displacement/position
owing to it's shape and the motion of the sensing core. An RVDT or syncro
resolver for rotational position hints at its role by the presence of the
rotatable shaft. A dew point sensor (related to humidity) can be recognized
by the presence of the mirror. A pressure sensor by a "port" into the device
(to which you could attach a length of hose to draw attention to that).

You could affix the sensor to an assembly to further hint at the
role that it plays. And, for a more interesting display, configure the
sensor to an *indicator* so that students can manipulate the mechanism
to see the sensor take effect and get a feel for how sensitive it may be.

Hi Don,

Op 27.10.22 om 10:32 schreef Don Y:

>> We are working on a setup where we want to show all kind of electronic
>> sensors. To link electronics with science, The idea is to provide the
>> visitor with a description of the internal working of a sensor, and
>> let them find the correct sensor in the batch.

> That may be hard -- unless you deliberately "load the deck" in favor of
> such discoveries because the "internals" of many aren't readily apparent.
> For example, a Hall Effect sensor can physically look like a temperature
> sensor
> (depending on the technology being used) with the only difference being the
> actual part numbers on the devices.

Well, the idea is that these sensors would also have some kind of
display with the measurement-data from the sensor.

So by -say- moving their hands over it, or blow in them, or move a
magnet over them, or move them around, they would see a change in
measurements (or not).

I agree, on sight, a lot of these sensors look alike. :-)

>
>> So I am looking for information on the internal working of different
>> kind of sensors.
>> For certain sensors, it is well known (hall-sensor, light-sensor, ...
>> ) and in certain cases it is described in the datasheets (laser-based
>> CO2-sensor or fine-particle dust-sensor).
>>
>> But I am looking for information on the following sensors / devices:
>> - temperature sensors
>> - air humidity
>> - gas (CO, VOC) that are not based on lasers
>> - hardware based gyroscopes
>
> If you only want the participants to *visually* examine the devices to
> ascertain their intent, perhaps you might want to pick a different
> set of sensors and technologies?
>
> E.g., an LVDT can typically be recognized as sensing displacement/position
> owing to it's shape and the motion of the sensing core.  An RVDT or syncro
> resolver for rotational position hints at its role by the presence of the
> rotatable shaft.  A dew point sensor (related to humidity) can be
> recognized
> by the presence of the mirror.  A pressure sensor by a "port" into the
> device
> (to which you could attach a length of hose to draw attention to that).

That is an interesting point.

E.g. a laser-based CO2 sensor has a light that flickers over couple of
seconds.

It's indeed a good point to mention the physical aspects of the sensor
(if there are) in the description.

> You could affix the sensor to an assembly to further hint at the
> role that it plays.  And, for a more interesting display, configure the
> sensor to an *indicator* so that students can manipulate the mechanism
> to see the sensor take effect and get a feel for how sensitive it may be.

That's indeed what we had in mind.

Cheerio! Kr. Bonne.

On 10/27/2022 3:49 AM, kristoff wrote:
> Op 27.10.22 om 10:32 schreef Don Y:
>
>>> We are working on a setup where we want to show all kind of electronic
>>> sensors. To link electronics with science, The idea is to provide the
>>> visitor with a description of the internal working of a sensor, and let them
>>> find the correct sensor in the batch.
>
>> That may be hard -- unless you deliberately "load the deck" in favor of
>> such discoveries because the "internals" of many aren't readily apparent.
>> For example, a Hall Effect sensor can physically look like a temperature sensor
>> (depending on the technology being used) with the only difference being the
>> actual part numbers on the devices.
>
> Well, the idea is that these sensors would also have some kind of display with
> the measurement-data from the sensor.
>
> So by -say- moving their hands over it, or blow in them, or move a magnet over
> them, or move them around, they would see a change in measurements (or not).
>
> I agree, on sight, a lot of these sensors look alike. :-)

Yes. So, all the student perceives is "magic"; the "why" behind the
sensing technology isn't apparent.

That;s why I suggested things like LVDT/RVDT -- a cutaway view (assuming
you don't want to incur the cost of destroying a working device) can
illustrate how the motion of the core alters the "circuit", even if
lacking in technical understanding.

Or, a chilled mirror dewpoint sensor -- folks can relate to "breathing"
on a cold mirror or piece of glass and seeing it "fog up" (humidity).
And, how warming the mirror eventually causes that manifestation to
cease.

>>> So I am looking for information on the internal working of different kind of
>>> sensors.
>>> For certain sensors, it is well known (hall-sensor, light-sensor, ... ) and
>>> in certain cases it is described in the datasheets (laser-based CO2-sensor
>>> or fine-particle dust-sensor).
>>>
>>> But I am looking for information on the following sensors / devices:
>>> - temperature sensors
>>> - air humidity
>>> - gas (CO, VOC) that are not based on lasers
>>> - hardware based gyroscopes
>>
>> If you only want the participants to *visually* examine the devices to
>> ascertain their intent, perhaps you might want to pick a different
>> set of sensors and technologies?
>>
>> E.g., an LVDT can typically be recognized as sensing displacement/position
>> owing to it's shape and the motion of the sensing core.  An RVDT or syncro
>> resolver for rotational position hints at its role by the presence of the
>> rotatable shaft.  A dew point sensor (related to humidity) can be recognized
>> by the presence of the mirror.  A pressure sensor by a "port" into the device
>> (to which you could attach a length of hose to draw attention to that).
>
> That is an interesting point.
>
> E.g. a laser-based CO2 sensor has a light that flickers over couple of seconds.
>
> It's indeed a good point to mention the physical aspects of the sensor (if
> there are) in the description.

Instead of trying to illustrate a wide variety of different sensors, you
might want to show how sensors can be used to "sense" other characteristics.

E.g., have a spring supported basket with an "indicator" taped to it.
Put a fixed mass in the basket and note the deflection (indicator against
a "scale"). Double the mass and again note the deflection.

"This is a characteristic of a spring"
"If we can measure the deflection (with an LVDT or other sensor),
then we can determine the WEIGHT of the item in the basket!"

I.e., we're sensing distance to determine mass -- just like the
chilled mirror uses temperature to determine moisture content.

Place a heat source near an RTD and monitor the sensed temperature.
Turn on a fan that moves the heat away from the sensor and note
the drop in temperature. I.e., we can now sense air flow.

Put a flowable substance in a container and measure the "depth"
of that substance and use that to predict its weight ("How does
this relationship change when the substance involved is changed?")
Or, the other way around: measure it's weight and predict the
"depth of fill".

Etc.

This puts a bit of "application" thinking into the mix as well as
making them think that you don't need a specific sensor for *each*
characteristic that you want to measure. It's not just poking and
prodding relatively static displays but, rather, trying to come to
grips with the "why" behind each observation -- and none of these
are difficult to "grok".

[No idea of the proficiency of your audience]

>> You could affix the sensor to an assembly to further hint at the
>> role that it plays.  And, for a more interesting display, configure the
>> sensor to an *indicator* so that students can manipulate the mechanism
>> to see the sensor take effect and get a feel for how sensitive it may be.
>
> That's indeed what we had in mind.

On 27/10/2022 07:30, kristoff wrote:
> Hi all,
>
>
> I don't know if this is the correct place to ask. Feel free to point me
> to an other NG if this is off-topic here.
>
>
>
> On the 27th of November, there is "de dag van de wetenschap" (the day of
> science) here in Belgium, and I am helping out a local fablab on this
> event.
>
> This event is aimed at kids between 14 and 18. I help out in the
> "electronics corner"
>
>
> We are working on a setup where we want to show all kind of electronic
> sensors. To link electronics with science, The idea is to provide the
> visitor with a description of the internal working of a sensor, and let
> them find the correct sensor in the batch.

OK but you might want to think about things that either look impressive
or will engage well with the teenage participants. Sensors these days
are very often boring black boxes with two or more leads coming out.

Obviously there are local and modern H&S considerations that some of my
suggestions below may well fall foul of. I was in the last cohort to
experience a real Maxwell's spur arcing and sparking as it spun up
dipped in mercury scattering tiny globules over the bench as it did so.

> So I am looking for information on the internal working of different
> kind of sensors.
> For certain sensors, it is well known (hall-sensor, light-sensor, ... )
> and in certain cases it is described in the datasheets (laser-based
> CO2-sensor or fine-particle dust-sensor).

Another nice optical one is sellotape on OHP slide and crossed polars. A
crude variant of the basic physics of many interference filters.

> But I am looking for information on the following sensors / devices:
> - temperature sensors

Any diode will do for this if opamps are around. Or thermistors.

LCD thermometer plastic sheet is impressive if your budget will stretch
to it (available from the likes of Edmund).

Hot wire wind velocity is another nice one (or traditional half ping
pong balls on a stick and a magnetic read off).

Stepper motor to measure angular rotation speed isn't bad either.

> - air humidity
> - gas (CO, VOC) that are not based on lasers

There are some starting around the £20 mark eg.
https://docs.rs-online.com/5489/0900766b815a66ca.pdf

> - hardware based gyroscopes

Best demo by far if you have the resources to make one is a bicycle
wheel on a longish spindle with lead pipe wrapped around it and a high
swivel chair. Put the victim on the chair and spin up the gyroscope then
when they try to move the axis of the gyroscope...

It really drives home the effect of a gyroscope to handle one on that
scale. Failing that the old toy lead ones that sit on an Eiffel tower.

Tesla coil and Jacob's ladder sparks make cool if RFI dense demos too.

--
Regards,
Martin Brown

kristoff wrote:
> Jan,
>
>
> Op 27.10.22 om 09:00 schreef Jan Panteltje:
>>> But I am looking for information on the following sensors / devices:
>>> - temperature sensors
>>> - air humidity
>>> - gas (CO, VOC) that are not based on lasers
>>> - hardware based gyroscopes
>>
>> Did you try google <sensor type wikipedia> ?
>
> Wait .. do you still use google?
>
>
> I am old enough to know about "netiquette". Yes, I did do my homework
> before posting :-)
>
>
> As said, for certain sensors, the datasheets do give me enough info to
> write a text for the 14-to-18 year audience.
>
>
> But take -say- a BME280/BMP280, the only thing I can make out from the
> datasheet is that pressure is messured by a piezzo-electric element.
> For temperature and humidy, no info.
>
>
> For the gyroscopes, I am wondering if they really messure the angular
> motion, or that they message lineair-motion in the x-y-z axis and then
> calculate angular motion based on that.

I suspect the gyros are acoustic and the pressure sensors are MEMS with
piezo_resistive_ readouts. (Straining silicon changes its conductivity.)

One useful shortcut is to look for patent numbers in the datasheets, and
look them up.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Contact the manufacturers; NXP, TI, Analog Devices, ST Microdevices, etc. Their sales reps will be happy to show up with box loads of toys. I have one sitting on my desk; a 10 year old ST Micro Mems evaluation module. A giveaway from a seminar. If you're not sure who the manufactures are go to Digikey and Mouser search for sensors. Get the info direct from the horse's mouth.

On Thu, 27 Oct 2022 08:30:14 +0200, kristoff <kristoff@skypro.be>
wrote:

>Hi all,
>
>
>I don't know if this is the correct place to ask. Feel free to point me
>to an other NG if this is off-topic here.
>
>
>
>On the 27th of November, there is "de dag van de wetenschap" (the day of
>science) here in Belgium, and I am helping out a local fablab on this event.
>
>This event is aimed at kids between 14 and 18. I help out in the
>"electronics corner"
>
>
>We are working on a setup where we want to show all kind of electronic
>sensors. To link electronics with science, The idea is to provide the
>visitor with a description of the internal working of a sensor, and let
>them find the correct sensor in the batch.
>
>
>
>So I am looking for information on the internal working of different
>kind of sensors.
>For certain sensors, it is well known (hall-sensor, light-sensor, ... )
>and in certain cases it is described in the datasheets (laser-based
>CO2-sensor or fine-particle dust-sensor).
>
>But I am looking for information on the following sensors / devices:
>- temperature sensors
>- air humidity
>- gas (CO, VOC) that are not based on lasers
>- hardware based gyroscopes
>
>
>Thanks!
>
>
>Cheerio! Kr. Bonne,

Liquid level sensors, capacitive and conductive, could be very visual
and very educational. Kids could pour different colored liquids in
from a pitcher, see it rise, see a meter and an LED go up. That would
be easy to set up too.

Aircraft fuel and oil level sensors are usually capacitive. One goal
of the instrumentation is to not explode the airplane; that has
happened. We make capacitive sensor simulators, which is interesting
too.

On 2022-10-27 18:24, John Larkin wrote:
> On Thu, 27 Oct 2022 08:30:14 +0200, kristoff <kristoff@skypro.be>
> wrote:
>
>> Hi all,
>>
>>
>> I don't know if this is the correct place to ask. Feel free to point me
>> to an other NG if this is off-topic here.
>>
>>
>>
>> On the 27th of November, there is "de dag van de wetenschap" (the day of
>> science) here in Belgium, and I am helping out a local fablab on this event.
>>
>> This event is aimed at kids between 14 and 18. I help out in the
>> "electronics corner"
>>
>>
>> We are working on a setup where we want to show all kind of electronic
>> sensors. To link electronics with science, The idea is to provide the
>> visitor with a description of the internal working of a sensor, and let
>> them find the correct sensor in the batch.
>>
>>
>>
>> So I am looking for information on the internal working of different
>> kind of sensors.
>> For certain sensors, it is well known (hall-sensor, light-sensor, ... )
>> and in certain cases it is described in the datasheets (laser-based
>> CO2-sensor or fine-particle dust-sensor).
>>
>> But I am looking for information on the following sensors / devices:
>> - temperature sensors
>> - air humidity
>> - gas (CO, VOC) that are not based on lasers
>> - hardware based gyroscopes
>>
>>
>> Thanks!
>>
>>
>> Cheerio! Kr. Bonne,
>
>
> Liquid level sensors, capacitive and conductive, could be very visual
> and very educational. Kids could pour different colored liquids in
> from a pitcher, see it rise, see a meter and an LED go up. That would
> be easy to set up too.
>
> Aircraft fuel and oil level sensors are usually capacitive. One goal
> of the instrumentation is to not explode the airplane; that has
> happened. We make capacitive sensor simulators, which is interesting
> too.
>

Weren't fuel gauges in cars wire-wound potentiometers immersed in
the fuel? They were 'safe' because the fuel to air ratio in the fuel
tank was way too rich to be combustible.

I made this cork gun with a piece of steel pipe and a spark plug.
Two drops of gas would pop the cork many meters into the air, but
one or three drops would do nothing.

Jeroen Belleman

On Thu, 27 Oct 2022 19:02:51 +0200, Jeroen Belleman
<jeroen@nospam.please> wrote:

>On 2022-10-27 18:24, John Larkin wrote:
>> On Thu, 27 Oct 2022 08:30:14 +0200, kristoff <kristoff@skypro.be>
>> wrote:
>>
>>> Hi all,
>>>
>>>
>>> I don't know if this is the correct place to ask. Feel free to point me
>>> to an other NG if this is off-topic here.
>>>
>>>
>>>
>>> On the 27th of November, there is "de dag van de wetenschap" (the day of
>>> science) here in Belgium, and I am helping out a local fablab on this event.
>>>
>>> This event is aimed at kids between 14 and 18. I help out in the
>>> "electronics corner"
>>>
>>>
>>> We are working on a setup where we want to show all kind of electronic
>>> sensors. To link electronics with science, The idea is to provide the
>>> visitor with a description of the internal working of a sensor, and let
>>> them find the correct sensor in the batch.
>>>
>>>
>>>
>>> So I am looking for information on the internal working of different
>>> kind of sensors.
>>> For certain sensors, it is well known (hall-sensor, light-sensor, ... )
>>> and in certain cases it is described in the datasheets (laser-based
>>> CO2-sensor or fine-particle dust-sensor).
>>>
>>> But I am looking for information on the following sensors / devices:
>>> - temperature sensors
>>> - air humidity
>>> - gas (CO, VOC) that are not based on lasers
>>> - hardware based gyroscopes
>>>
>>>
>>> Thanks!
>>>
>>>
>>> Cheerio! Kr. Bonne,
>>
>>
>> Liquid level sensors, capacitive and conductive, could be very visual
>> and very educational. Kids could pour different colored liquids in
>> from a pitcher, see it rise, see a meter and an LED go up. That would
>> be easy to set up too.
>>
>> Aircraft fuel and oil level sensors are usually capacitive. One goal
>> of the instrumentation is to not explode the airplane; that has
>> happened. We make capacitive sensor simulators, which is interesting
>> too.
>>
>
>Weren't fuel gauges in cars wire-wound potentiometers immersed in
>the fuel? They were 'safe' because the fuel to air ratio in the fuel
>tank was way too rich to be combustible.

Yes. I think that airplanes now ensure a non-combustible fuel tank.

The capacitive level sensors also have wildly redundant intrinsic
safety networks, lots of resistors and zeners. Suits me, since the
protection networks add a lot of capacitance that makes simulation
more interesting.

On Thursday, October 27, 2022 at 2:30:21 AM UTC-4, kristoff wrote:
> Hi all,
>
>
> I don't know if this is the correct place to ask. Feel free to point me
> to an other NG if this is off-topic here.
>
>
>
> On the 27th of November, there is "de dag van de wetenschap" (the day of
> science) here in Belgium, and I am helping out a local fablab on this event.
>
> This event is aimed at kids between 14 and 18. I help out in the
> "electronics corner"
>
>
> We are working on a setup where we want to show all kind of electronic
> sensors. To link electronics with science, The idea is to provide the
> visitor with a description of the internal working of a sensor, and let
> them find the correct sensor in the batch.
>
>
>
> So I am looking for information on the internal working of different
> kind of sensors.
> For certain sensors, it is well known (hall-sensor, light-sensor, ... )
> and in certain cases it is described in the datasheets (laser-based
> CO2-sensor or fine-particle dust-sensor).
>
> But I am looking for information on the following sensors / devices:
> - temperature sensors
> - air humidity
> - gas (CO, VOC) that are not based on lasers
> - hardware based gyroscopes

You want to take a look at the numerous publications of Forrest Mims. He's an absolutely brilliant writer, and most of his work is centered on communicating with the audience you describe. He put together a bunch of hardware based courses for Radio Shack, and they're surprisingly excellent. A lot of the copyrights are expired so there are ample copies on the internet you can download free.

Like this one:

https://www.n5dux.com/ham/files/pdf/Forrest%20Mims%20-%20Sensor%20Projects.pdf

There are bunches more.

For more cutting edge state-of-the-art stuff, dunno if he has anything recent, you might have to look elsewhere.

>
>
> Thanks!
>
>
> Cheerio! Kr. Bonne,

On Thursday, October 27, 2022 at 1:20:27 PM UTC-4, John Larkin wrote:
> On Thu, 27 Oct 2022 19:02:51 +0200, Jeroen Belleman
> <jer...@nospam.please> wrote:
>
> >On 2022-10-27 18:24, John Larkin wrote:
> >> On Thu, 27 Oct 2022 08:30:14 +0200, kristoff <kris...@skypro.be>
> >> wrote:
> >>
> >>> Hi all,
> >>>
> >>>
> >>> I don't know if this is the correct place to ask. Feel free to point me
> >>> to an other NG if this is off-topic here.
> >>>
> >>>
> >>>
> >>> On the 27th of November, there is "de dag van de wetenschap" (the day of
> >>> science) here in Belgium, and I am helping out a local fablab on this event.
> >>>
> >>> This event is aimed at kids between 14 and 18. I help out in the
> >>> "electronics corner"
> >>>
> >>>
> >>> We are working on a setup where we want to show all kind of electronic
> >>> sensors. To link electronics with science, The idea is to provide the
> >>> visitor with a description of the internal working of a sensor, and let
> >>> them find the correct sensor in the batch.
> >>>
> >>>
> >>>
> >>> So I am looking for information on the internal working of different
> >>> kind of sensors.
> >>> For certain sensors, it is well known (hall-sensor, light-sensor, ... )
> >>> and in certain cases it is described in the datasheets (laser-based
> >>> CO2-sensor or fine-particle dust-sensor).
> >>>
> >>> But I am looking for information on the following sensors / devices:
> >>> - temperature sensors
> >>> - air humidity
> >>> - gas (CO, VOC) that are not based on lasers
> >>> - hardware based gyroscopes
> >>>
> >>>
> >>> Thanks!
> >>>
> >>>
> >>> Cheerio! Kr. Bonne,
> >>
> >>
> >> Liquid level sensors, capacitive and conductive, could be very visual
> >> and very educational. Kids could pour different colored liquids in
> >> from a pitcher, see it rise, see a meter and an LED go up. That would
> >> be easy to set up too.
> >>
> >> Aircraft fuel and oil level sensors are usually capacitive. One goal
> >> of the instrumentation is to not explode the airplane; that has
> >> happened. We make capacitive sensor simulators, which is interesting
> >> too.
> >>
> >
> >Weren't fuel gauges in cars wire-wound potentiometers immersed in
> >the fuel? They were 'safe' because the fuel to air ratio in the fuel
> >tank was way too rich to be combustible.
> Yes. I think that airplanes now ensure a non-combustible fuel tank.
>
> The capacitive level sensors also have wildly redundant intrinsic
> safety networks, lots of resistors and zeners. Suits me, since the
> protection networks add a lot of capacitance that makes simulation
> more interesting.

Still don't protect against defective wiring insulation putting a high voltage arc into their sensor...

And it wasn't the level gauge sensor submerged in liquid gasoline, it was the electric fuel pump itself. The gasoline helped keep the motor winding cools too.

On Thursday, October 27, 2022 at 2:30:21 AM UTC-4, kristoff wrote:
> Hi all,
>
>
> I don't know if this is the correct place to ask. Feel free to point me
> to an other NG if this is off-topic here.
>
>
>
> On the 27th of November, there is "de dag van de wetenschap" (the day of
> science) here in Belgium, and I am helping out a local fablab on this event.
>
> This event is aimed at kids between 14 and 18. I help out in the
> "electronics corner"
>
>
> We are working on a setup where we want to show all kind of electronic
> sensors. To link electronics with science, The idea is to provide the
> visitor with a description of the internal working of a sensor, and let
> them find the correct sensor in the batch.
>
>
>
> So I am looking for information on the internal working of different
> kind of sensors.
> For certain sensors, it is well known (hall-sensor, light-sensor, ... )
> and in certain cases it is described in the datasheets (laser-based
> CO2-sensor or fine-particle dust-sensor).
>
> But I am looking for information on the following sensors / devices:
> - temperature sensors
> - air humidity
> - gas (CO, VOC) that are not based on lasers
> - hardware based gyroscopes
>
>
> Thanks!
>
>
> Cheerio! Kr. Bonne,

Some sensor applications on the more imaginative side:
https://gizmodo.com/seven-mostly-scientific-devices-for-measuring-sexual-5214130

On Thursday, October 27, 2022 at 4:32:22 AM UTC-4, Don Y wrote:
> On 10/26/2022 11:30 PM, kristoff wrote:
> > On the 27th of November, there is "de dag van de wetenschap" (the day of
> > science) here in Belgium, and I am helping out a local fablab on this event.
> >
> > This event is aimed at kids between 14 and 18. I help out in the "electronics
> > corner"
> >
> > We are working on a setup where we want to show all kind of electronic sensors.
> > To link electronics with science, The idea is to provide the visitor with a
> > description of the internal working of a sensor, and let them find the correct
> > sensor in the batch.
> That may be hard -- unless you deliberately "load the deck" in favor of
> such discoveries because the "internals" of many aren't readily apparent.
>
> For example, a Hall Effect sensor can physically look like a temperature sensor
> (depending on the technology being used) with the only difference being the
> actual part numbers on the devices.
> > So I am looking for information on the internal working of different kind of
> > sensors.
> > For certain sensors, it is well known (hall-sensor, light-sensor, ... ) and in
> > certain cases it is described in the datasheets (laser-based CO2-sensor or
> > fine-particle dust-sensor).
> >
> > But I am looking for information on the following sensors / devices:
> > - temperature sensors
> > - air humidity
> > - gas (CO, VOC) that are not based on lasers
> > - hardware based gyroscopes
> If you only want the participants to *visually* examine the devices to
> ascertain their intent, perhaps you might want to pick a different
> set of sensors and technologies?
>
> E.g., an LVDT can typically be recognized as sensing displacement/position
> owing to it's shape and the motion of the sensing core. An RVDT or syncro
> resolver for rotational position hints at its role by the presence of the
> rotatable shaft. A dew point sensor (related to humidity) can be recognized
> by the presence of the mirror. A pressure sensor by a "port" into the device
> (to which you could attach a length of hose to draw attention to that).
>
> You could affix the sensor to an assembly to further hint at the
> role that it plays. And, for a more interesting display, configure the
> sensor to an *indicator* so that students can manipulate the mechanism
> to see the sensor take effect and get a feel for how sensitive it may be.

He can do a demonstration for the students with this marvel:

SawStop Safety System stops on contact with skin

https://www.sawstop.com/product/compact-table-saw/

The product price must reflect the liability insurance. They've been in business for a quite a while. Protecting the hands is a very tricky challenge because things happen so fast and the hands are surprisingly vulnerable to nerve damage making them unusable despite being fully intact.

On 10/27/2022 11:17 AM, Fred Bloggs wrote:
> On Thursday, October 27, 2022 at 4:32:22 AM UTC-4, Don Y wrote:
>> On 10/26/2022 11:30 PM, kristoff wrote:
>>> On the 27th of November, there is "de dag van de wetenschap" (the day
>>> of science) here in Belgium, and I am helping out a local fablab on this
>>> event.
>>>
>>> This event is aimed at kids between 14 and 18. I help out in the
>>> "electronics corner"
>>>
>>> We are working on a setup where we want to show all kind of electronic
>>> sensors. To link electronics with science, The idea is to provide the
>>> visitor with a description of the internal working of a sensor, and let
>>> them find the correct sensor in the batch.
>> That may be hard -- unless you deliberately "load the deck" in favor of
>> such discoveries because the "internals" of many aren't readily apparent.
>>
>> For example, a Hall Effect sensor can physically look like a temperature
>> sensor (depending on the technology being used) with the only difference
>> being the actual part numbers on the devices.
>>> So I am looking for information on the internal working of different
>>> kind of sensors. For certain sensors, it is well known (hall-sensor,
>>> light-sensor, ... ) and in certain cases it is described in the
>>> datasheets (laser-based CO2-sensor or fine-particle dust-sensor).
>>>
>>> But I am looking for information on the following sensors / devices: -
>>> temperature sensors - air humidity - gas (CO, VOC) that are not based on
>>> lasers - hardware based gyroscopes
>> If you only want the participants to *visually* examine the devices to
>> ascertain their intent, perhaps you might want to pick a different set of
>> sensors and technologies?
>>
>> E.g., an LVDT can typically be recognized as sensing
>> displacement/position owing to it's shape and the motion of the sensing
>> core. An RVDT or syncro resolver for rotational position hints at its role
>> by the presence of the rotatable shaft. A dew point sensor (related to
>> humidity) can be recognized by the presence of the mirror. A pressure
>> sensor by a "port" into the device (to which you could attach a length of
>> hose to draw attention to that).
>>
>> You could affix the sensor to an assembly to further hint at the role that
>> it plays. And, for a more interesting display, configure the sensor to an
>> *indicator* so that students can manipulate the mechanism to see the
>> sensor take effect and get a feel for how sensitive it may be.
>
> He can do a demonstration for the students with this marvel:
>
> SawStop Safety System stops on contact with skin
>
> https://www.sawstop.com/product/compact-table-saw/
>
> The product price must reflect the liability insurance. They've been in
> business for a quite a while. Protecting the hands is a very tricky
> challenge because things happen so fast and the hands are surprisingly
> vulnerable to nerve damage making them unusable despite being fully intact.

If its the system I've seen, it's a one-time event; you have to
replace the "module" whenever it has been "exercised".

Regardless, the mechanism by which it works wouldn't be obvious.
SEEING something work and UNDERSTANDING why it works are very
different.

Hence the other examples (elsewhere) I've given; you can grok how
they work, on casual inspection.

On Thursday, October 27, 2022 at 2:52:58 PM UTC-4, Don Y wrote:
> On 10/27/2022 11:17 AM, Fred Bloggs wrote:
> > On Thursday, October 27, 2022 at 4:32:22 AM UTC-4, Don Y wrote:
> >> On 10/26/2022 11:30 PM, kristoff wrote:
> >>> On the 27th of November, there is "de dag van de wetenschap" (the day
> >>> of science) here in Belgium, and I am helping out a local fablab on this
> >>> event.
> >>>
> >>> This event is aimed at kids between 14 and 18. I help out in the
> >>> "electronics corner"
> >>>
> >>> We are working on a setup where we want to show all kind of electronic
> >>> sensors. To link electronics with science, The idea is to provide the
> >>> visitor with a description of the internal working of a sensor, and let
> >>> them find the correct sensor in the batch.
> >> That may be hard -- unless you deliberately "load the deck" in favor of
> >> such discoveries because the "internals" of many aren't readily apparent.
> >>
> >> For example, a Hall Effect sensor can physically look like a temperature
> >> sensor (depending on the technology being used) with the only difference
> >> being the actual part numbers on the devices.
> >>> So I am looking for information on the internal working of different
> >>> kind of sensors. For certain sensors, it is well known (hall-sensor,
> >>> light-sensor, ... ) and in certain cases it is described in the
> >>> datasheets (laser-based CO2-sensor or fine-particle dust-sensor).
> >>>
> >>> But I am looking for information on the following sensors / devices: -
> >>> temperature sensors - air humidity - gas (CO, VOC) that are not based on
> >>> lasers - hardware based gyroscopes
> >> If you only want the participants to *visually* examine the devices to
> >> ascertain their intent, perhaps you might want to pick a different set of
> >> sensors and technologies?
> >>
> >> E.g., an LVDT can typically be recognized as sensing
> >> displacement/position owing to it's shape and the motion of the sensing
> >> core. An RVDT or syncro resolver for rotational position hints at its role
> >> by the presence of the rotatable shaft. A dew point sensor (related to
> >> humidity) can be recognized by the presence of the mirror. A pressure
> >> sensor by a "port" into the device (to which you could attach a length of
> >> hose to draw attention to that).
> >>
> >> You could affix the sensor to an assembly to further hint at the role that
> >> it plays. And, for a more interesting display, configure the sensor to an
> >> *indicator* so that students can manipulate the mechanism to see the
> >> sensor take effect and get a feel for how sensitive it may be.
> >
> > He can do a demonstration for the students with this marvel:
> >
> > SawStop Safety System stops on contact with skin
> >
> > https://www.sawstop.com/product/compact-table-saw/
> >
> > The product price must reflect the liability insurance. They've been in
> > business for a quite a while. Protecting the hands is a very tricky
> > challenge because things happen so fast and the hands are surprisingly
> > vulnerable to nerve damage making them unusable despite being fully intact.
> If its the system I've seen, it's a one-time event; you have to
> replace the "module" whenever it has been "exercised".

Yeah? How often do you expect it to be exercised? You're not going to non-destructively stop a 4,000 RPM rotating saw blade in under 5 ms without damage.

https://www.youtube.com/watch?v=beEunPSSgkQ

>
> Regardless, the mechanism by which it works wouldn't be obvious.
> SEEING something work and UNDERSTANDING why it works are very
> different.

Not why it works, how it works. Demonstration testing uses a hot dog to simulate human flesh. It stops the saw instantaneously with an sacrificial interference brake. Looks like you need to replace the saw blade in addition to the brake cartridge. Reckless people can't afford to own this machine.

>
> Hence the other examples (elsewhere) I've given; you can grok how
> they work, on casual inspection.

grok? ookay...

torsdag den 27. oktober 2022 kl. 22.56.12 UTC+2 skrev Fred Bloggs:
> On Thursday, October 27, 2022 at 2:52:58 PM UTC-4, Don Y wrote:
> > On 10/27/2022 11:17 AM, Fred Bloggs wrote:
> > > On Thursday, October 27, 2022 at 4:32:22 AM UTC-4, Don Y wrote:
> > >> On 10/26/2022 11:30 PM, kristoff wrote:
> > >>> On the 27th of November, there is "de dag van de wetenschap" (the day
> > >>> of science) here in Belgium, and I am helping out a local fablab on this
> > >>> event.
> > >>>
> > >>> This event is aimed at kids between 14 and 18. I help out in the
> > >>> "electronics corner"
> > >>>
> > >>> We are working on a setup where we want to show all kind of electronic
> > >>> sensors. To link electronics with science, The idea is to provide the
> > >>> visitor with a description of the internal working of a sensor, and let
> > >>> them find the correct sensor in the batch.
> > >> That may be hard -- unless you deliberately "load the deck" in favor of
> > >> such discoveries because the "internals" of many aren't readily apparent.
> > >>
> > >> For example, a Hall Effect sensor can physically look like a temperature
> > >> sensor (depending on the technology being used) with the only difference
> > >> being the actual part numbers on the devices.
> > >>> So I am looking for information on the internal working of different
> > >>> kind of sensors. For certain sensors, it is well known (hall-sensor,
> > >>> light-sensor, ... ) and in certain cases it is described in the
> > >>> datasheets (laser-based CO2-sensor or fine-particle dust-sensor).
> > >>>
> > >>> But I am looking for information on the following sensors / devices: -
> > >>> temperature sensors - air humidity - gas (CO, VOC) that are not based on
> > >>> lasers - hardware based gyroscopes
> > >> If you only want the participants to *visually* examine the devices to
> > >> ascertain their intent, perhaps you might want to pick a different set of
> > >> sensors and technologies?
> > >>
> > >> E.g., an LVDT can typically be recognized as sensing
> > >> displacement/position owing to it's shape and the motion of the sensing
> > >> core. An RVDT or syncro resolver for rotational position hints at its role
> > >> by the presence of the rotatable shaft. A dew point sensor (related to
> > >> humidity) can be recognized by the presence of the mirror. A pressure
> > >> sensor by a "port" into the device (to which you could attach a length of
> > >> hose to draw attention to that).
> > >>
> > >> You could affix the sensor to an assembly to further hint at the role that
> > >> it plays. And, for a more interesting display, configure the sensor to an
> > >> *indicator* so that students can manipulate the mechanism to see the
> > >> sensor take effect and get a feel for how sensitive it may be.
> > >
> > > He can do a demonstration for the students with this marvel:
> > >
> > > SawStop Safety System stops on contact with skin
> > >
> > > https://www.sawstop.com/product/compact-table-saw/
> > >
> > > The product price must reflect the liability insurance. They've been in
> > > business for a quite a while. Protecting the hands is a very tricky
> > > challenge because things happen so fast and the hands are surprisingly
> > > vulnerable to nerve damage making them unusable despite being fully intact.
> > If its the system I've seen, it's a one-time event; you have to
> > replace the "module" whenever it has been "exercised".
> Yeah? How often do you expect it to be exercised? You're not going to non-destructively stop a 4,000 RPM rotating saw blade in under 5 ms without damage.
>
> https://www.youtube.com/watch?v=beEunPSSgkQ
> >
> > Regardless, the mechanism by which it works wouldn't be obvious.
> > SEEING something work and UNDERSTANDING why it works are very
> > different.
> Not why it works, how it works. Demonstration testing uses a hot dog to simulate human flesh. It stops the saw instantaneously with an sacrificial interference brake. Looks like you need to replace the saw blade in addition to the brake cartridge. Reckless people can't afford to own this machine.
>

reckless people will run out of fingers, the cartridge is less than $100 you don't get a new finger for that ...

On 10/27/2022 1:56 PM, Fred Bloggs wrote:
> On Thursday, October 27, 2022 at 2:52:58 PM UTC-4, Don Y wrote:
>> On 10/27/2022 11:17 AM, Fred Bloggs wrote:
>>> On Thursday, October 27, 2022 at 4:32:22 AM UTC-4, Don Y wrote:
>>>> On 10/26/2022 11:30 PM, kristoff wrote:
>>>>> On the 27th of November, there is "de dag van de wetenschap" (the
>>>>> day of science) here in Belgium, and I am helping out a local fablab
>>>>> on this event.
>>>>>
>>>>> This event is aimed at kids between 14 and 18. I help out in the
>>>>> "electronics corner"
>>>>>
>>>>> We are working on a setup where we want to show all kind of
>>>>> electronic sensors. To link electronics with science, The idea is to
>>>>> provide the visitor with a description of the internal working of a
>>>>> sensor, and let them find the correct sensor in the batch.
>>>> That may be hard -- unless you deliberately "load the deck" in favor
>>>> of such discoveries because the "internals" of many aren't readily
>>>> apparent.
>>>>
>>>> For example, a Hall Effect sensor can physically look like a
>>>> temperature sensor (depending on the technology being used) with the
>>>> only difference being the actual part numbers on the devices.
>>>>> So I am looking for information on the internal working of
>>>>> different kind of sensors. For certain sensors, it is well known
>>>>> (hall-sensor, light-sensor, ... ) and in certain cases it is
>>>>> described in the datasheets (laser-based CO2-sensor or fine-particle
>>>>> dust-sensor).
>>>>>
>>>>> But I am looking for information on the following sensors / devices:
>>>>> - temperature sensors - air humidity - gas (CO, VOC) that are not
>>>>> based on lasers - hardware based gyroscopes
>>>> If you only want the participants to *visually* examine the devices
>>>> to ascertain their intent, perhaps you might want to pick a different
>>>> set of sensors and technologies?
>>>>
>>>> E.g., an LVDT can typically be recognized as sensing
>>>> displacement/position owing to it's shape and the motion of the
>>>> sensing core. An RVDT or syncro resolver for rotational position hints
>>>> at its role by the presence of the rotatable shaft. A dew point sensor
>>>> (related to humidity) can be recognized by the presence of the mirror.
>>>> A pressure sensor by a "port" into the device (to which you could
>>>> attach a length of hose to draw attention to that).
>>>>
>>>> You could affix the sensor to an assembly to further hint at the role
>>>> that it plays. And, for a more interesting display, configure the
>>>> sensor to an *indicator* so that students can manipulate the mechanism
>>>> to see the sensor take effect and get a feel for how sensitive it may
>>>> be.
>>>
>>> He can do a demonstration for the students with this marvel:
>>>
>>> SawStop Safety System stops on contact with skin
>>>
>>> https://www.sawstop.com/product/compact-table-saw/
>>>
>>> The product price must reflect the liability insurance. They've been in
>>> business for a quite a while. Protecting the hands is a very tricky
>>> challenge because things happen so fast and the hands are surprisingly
>>> vulnerable to nerve damage making them unusable despite being fully
>>> intact.
>> If its the system I've seen, it's a one-time event; you have to replace
>> the "module" whenever it has been "exercised".
>
> Yeah? How often do you expect it to be exercised? You're not going to
> non-destructively stop a 4,000 RPM rotating saw blade in under 5 ms without
> damage.

Local Maker House is often complaining about it "activating" too often
(as the replacement "cartridges" aren't cheap for a group that is
perpetually worrying about how to pay rent -- apparently a common problem
in member funded maker houses)

>> Regardless, the mechanism by which it works wouldn't be obvious. SEEING
>> something work and UNDERSTANDING why it works are very different.
>
> Not why it works, how it works. Demonstration testing uses a hot dog to
> simulate human flesh. It stops the saw instantaneously with an sacrificial
> interference brake. Looks like you need to replace the saw blade in addition
> to the brake cartridge. Reckless people can't afford to own this machine.

But the OP wants the attendees to understand HOW the sensors "do their
thing"

>> Hence the other examples (elsewhere) I've given; you can grok how they
>> work, on casual inspection.
>
> grok? ookay...

Perhaps you're too young to have been exposed to the literature?

<https://en.wikipedia.org/wiki/Grok>

Different term than "understand".

fredag den 28. oktober 2022 kl. 00.14.41 UTC+2 skrev Don Y:
> On 10/27/2022 1:56 PM, Fred Bloggs wrote:
> > On Thursday, October 27, 2022 at 2:52:58 PM UTC-4, Don Y wrote:
> >> On 10/27/2022 11:17 AM, Fred Bloggs wrote:
> >>> On Thursday, October 27, 2022 at 4:32:22 AM UTC-4, Don Y wrote:
> >>>> On 10/26/2022 11:30 PM, kristoff wrote:
> >>>>> On the 27th of November, there is "de dag van de wetenschap" (the
> >>>>> day of science) here in Belgium, and I am helping out a local fablab
> >>>>> on this event.
> >>>>>
> >>>>> This event is aimed at kids between 14 and 18. I help out in the
> >>>>> "electronics corner"
> >>>>>
> >>>>> We are working on a setup where we want to show all kind of
> >>>>> electronic sensors. To link electronics with science, The idea is to
> >>>>> provide the visitor with a description of the internal working of a
> >>>>> sensor, and let them find the correct sensor in the batch.
> >>>> That may be hard -- unless you deliberately "load the deck" in favor
> >>>> of such discoveries because the "internals" of many aren't readily
> >>>> apparent.
> >>>>
> >>>> For example, a Hall Effect sensor can physically look like a
> >>>> temperature sensor (depending on the technology being used) with the
> >>>> only difference being the actual part numbers on the devices.
> >>>>> So I am looking for information on the internal working of
> >>>>> different kind of sensors. For certain sensors, it is well known
> >>>>> (hall-sensor, light-sensor, ... ) and in certain cases it is
> >>>>> described in the datasheets (laser-based CO2-sensor or fine-particle
> >>>>> dust-sensor).
> >>>>>
> >>>>> But I am looking for information on the following sensors / devices:
> >>>>> - temperature sensors - air humidity - gas (CO, VOC) that are not
> >>>>> based on lasers - hardware based gyroscopes
> >>>> If you only want the participants to *visually* examine the devices
> >>>> to ascertain their intent, perhaps you might want to pick a different
> >>>> set of sensors and technologies?
> >>>>
> >>>> E.g., an LVDT can typically be recognized as sensing
> >>>> displacement/position owing to it's shape and the motion of the
> >>>> sensing core. An RVDT or syncro resolver for rotational position hints
> >>>> at its role by the presence of the rotatable shaft. A dew point sensor
> >>>> (related to humidity) can be recognized by the presence of the mirror.
> >>>> A pressure sensor by a "port" into the device (to which you could
> >>>> attach a length of hose to draw attention to that).
> >>>>
> >>>> You could affix the sensor to an assembly to further hint at the role
> >>>> that it plays. And, for a more interesting display, configure the
> >>>> sensor to an *indicator* so that students can manipulate the mechanism
> >>>> to see the sensor take effect and get a feel for how sensitive it may
> >>>> be.
> >>>
> >>> He can do a demonstration for the students with this marvel:
> >>>
> >>> SawStop Safety System stops on contact with skin
> >>>
> >>> https://www.sawstop.com/product/compact-table-saw/
> >>>
> >>> The product price must reflect the liability insurance. They've been in
> >>> business for a quite a while. Protecting the hands is a very tricky
> >>> challenge because things happen so fast and the hands are surprisingly
> >>> vulnerable to nerve damage making them unusable despite being fully
> >>> intact.
> >> If its the system I've seen, it's a one-time event; you have to replace
> >> the "module" whenever it has been "exercised".
> >
> > Yeah? How often do you expect it to be exercised? You're not going to
> > non-destructively stop a 4,000 RPM rotating saw blade in under 5 ms without
> > damage.
> Local Maker House is often complaining about it "activating" too often
> (as the replacement "cartridges" aren't cheap for a group that is
> perpetually worrying about how to pay rent -- apparently a common problem
> in member funded maker houses)

they don't make people pay for triggering it? they either avoided injury or did
something dumb (it has a test mode to test if something will trigger it)

or have people pay a small fee to a cartridge fund if they want to use the tablesaw

On 10/27/2022 3:31 PM, Lasse Langwadt Christensen wrote:
> fredag den 28. oktober 2022 kl. 00.14.41 UTC+2 skrev Don Y:

>> Local Maker House is often complaining about it "activating" too often
>> (as the replacement "cartridges" aren't cheap for a group that is
>> perpetually worrying about how to pay rent -- apparently a common problem
>> in member funded maker houses)
>
> they don't make people pay for triggering it? they either avoided injury or did
> something dumb (it has a test mode to test if something will trigger it)

No. Everyone is supposed to have been trained before using each piece
of equipment. And, a "shop manager" (one for each different shop) is supposed
to be on hand when anything in that shop is in use.

> or have people pay a small fee to a cartridge fund if they want to use the tablesaw

I don't set policy (I'm not even a member as they have nothing that I need).
I think they likely fear that associating additional POTENTIAL costs with
items will discourage use and, thus, membership.

I don't really understand how they can keep the doors open at $50/member/month,
given that most folks "have a life" and can't make extensive use of their
facilities. Would you want to drive across town (30+ minutes for me) to
use a tool(s) for an hour or so, then drive back home (with your "project")
again... only to repeat the effort the next time you need another tool?

Why not take the monies and buy your own tools??

(Of course, {metal,wood}-lathe or mill might be out of reach but you
don't *need* a table saw to cut wood, etc.)

fredag den 28. oktober 2022 kl. 00.47.17 UTC+2 skrev Don Y:
> On 10/27/2022 3:31 PM, Lasse Langwadt Christensen wrote:
> > fredag den 28. oktober 2022 kl. 00.14.41 UTC+2 skrev Don Y:
>
> >> Local Maker House is often complaining about it "activating" too often
> >> (as the replacement "cartridges" aren't cheap for a group that is
> >> perpetually worrying about how to pay rent -- apparently a common problem
> >> in member funded maker houses)
> >
> > they don't make people pay for triggering it? they either avoided injury or did
> > something dumb (it has a test mode to test if something will trigger it)
> No. Everyone is supposed to have been trained before using each piece
> of equipment. And, a "shop manager" (one for each different shop) is supposed
> to be on hand when anything in that shop is in use.
> > or have people pay a small fee to a cartridge fund if they want to use the tablesaw
> I don't set policy (I'm not even a member as they have nothing that I need).
> I think they likely fear that associating additional POTENTIAL costs with
> items will discourage use and, thus, membership.
>
> I don't really understand how they can keep the doors open at $50/member/month,

There's a makerspace here it is ~$20/month half price for students
Though they don't pay rent the location is provided by the municipality and I think they
also get some subsidies by the government, like other non-profit organizations with an educational purpose

> given that most folks "have a life" and can't make extensive use of their
> facilities. Would you want to drive across town (30+ minutes for me) to
> use a tool(s) for an hour or so, then drive back home (with your "project")
> again... only to repeat the effort the next time you need another tool?

yeh, you have to plan ahead

> Why not take the monies and buy your own tools??
>
> (Of course, {metal,wood}-lathe or mill might be out of reach but you
> don't *need* a table saw to cut wood, etc.)

you don't _need_ most tools, but they make it a lot easier
and $50 is going to takes years to buy a decent metal lathe or table say

On 10/27/2022 4:18 PM, Lasse Langwadt Christensen wrote:

>> I don't set policy (I'm not even a member as they have nothing that I
>> need). I think they likely fear that associating additional POTENTIAL
>> costs with items will discourage use and, thus, membership.
>>
>> I don't really understand how they can keep the doors open at
>> $50/member/month,
>
> There's a makerspace here it is ~$20/month half price for students Though
> they don't pay rent the location is provided by the municipality and I think
> they also get some subsidies by the government, like other non-profit
> organizations with an educational purpose

Not the case, here. You pay rent. You pay your own utilities.
You pay for your own liability insurance. etc.

You can *apply* for grants (both from the gummit and other
"benevolent organizations") but there are no guarantees as
you are competing with other people for a fixed size pot of money.

I'm sure the $50 was determined based on "average membership"
(which can vary month-to-month) and "operating costs" -- I
don't think there are any "paid staff" though there may be
some services -- accounting, legal, etc. -- that have to
be compensated with currency (instead of in-kind).

>> given that most folks "have a life" and can't make extensive use of their
>> facilities. Would you want to drive across town (30+ minutes for me) to
>> use a tool(s) for an hour or so, then drive back home (with your
>> "project") again... only to repeat the effort the next time you need
>> another tool?
>
> yeh, you have to plan ahead

So, folks bu a monthly (or quarterly) membership when they are
ready to START work on their "project". And, hope to complete it
before their purchase needs renewal. The organization can't
count on them as an ongoing source of funds (unless they are
constantly coming up with new "projects")

I looked into them for their laser cutter. Then, realized an easier
way of achieving the same result without that tool.

Likewise, their 3D printers -- why spend an evening watching one of
theirs print a part when I can just send off the design to a service
bureau and go about my daily business while the parts are made?

>> Why not take the monies and buy your own tools??
>>
>> (Of course, {metal,wood}-lathe or mill might be out of reach but you don't
>> *need* a table saw to cut wood, etc.)
>
> you don't _need_ most tools, but they make it a lot easier and $50 is going
> to takes years to buy a decent metal lathe or table say

But are YOU going to want a lathe? Do YOU *need* that table saw?
Or, can you do the same thing with a saw guide, circular saw and
a brand new blade? Without having to transport your work pieces
to and fro?

I see lots of members are college students, likely not having to
worry about "families" expecting them home for dinner, etc.
And, if not "party goers", it may be the only real social outlet
that they have available.

I suspect some volunteer their time in exchange for "membership time"
(especially if they are using the place as a social outlet).

Can't imagine a husband-father spending any more time there than
absolutely essential. And, having to justify to family his $50/month
"habit". (I guess it's cheaper than drinking or smoking but how
many nights do you think the wife would want to be "stuck" with the kids?)