I'm trying to find a display to use with a Pi that will be readable in
direct sunlight (on a boat).

I can find LCD numeric displays using the Hitachi HD44780 interface
and they work OK in the sun but I'm after a graphic display of some
sort. It needs to be a reasonable size, so all the 128 x 64 ones are
too small really. Something like a 7" display would be ideal.

Does anyone here know of anything like this that doesn't cost hundreds
of pounds?

--
Chris Green
·

On 29/07/2023 09:46, Chris Green wrote:
> I'm trying to find a display to use with a Pi that will be readable in
> direct sunlight (on a boat).
>
> I can find LCD numeric displays using the Hitachi HD44780 interface
> and they work OK in the sun but I'm after a graphic display of some
> sort. It needs to be a reasonable size, so all the 128 x 64 ones are
> too small really. Something like a 7" display would be ideal.
>
> Does anyone here know of anything like this that doesn't cost hundreds
> of pounds?

Chris,

If an update rate of, say, 30 seconds is adequate, and a 74 mm diagonal is
adequate, you could look at the Pimoroni Badger - 296 x 128 pixels. Available
plain, or with embedded wireless:

https://shop.pimoroni.com/products/badger-2040?variant=39752959852627

https://shop.pimoroni.com/products/badger-2040-w?variant=40514062188627

Using two lines of characters it's readable at 2m away. Program with Python -
many examples and help easily available.

--
Cheers,
David
Web: https://www.satsignal.eu

On 29/07/2023 09:46, Chris Green wrote:
> I'm trying to find a display to use with a Pi that will be readable in
> direct sunlight (on a boat).

E-paper is the correct technology

> I can find LCD numeric displays using the Hitachi HD44780 interface
> and they work OK in the sun but I'm after a graphic display of some
> sort. It needs to be a reasonable size, so all the 128 x 64 ones are
> too small really. Something like a 7" display would be ideal.
>
> Does anyone here know of anything like this that doesn't cost hundreds
> of pounds?
>
E-paper up to around 400x300 is not hard to find, but 7" is a bit harder.
https://thepihut.com/products/4-2-e-paper-display-module-for-raspberry-pi-pico-black-white-400x300
is a pico product.
- 4 and a bit inches

This is a great compromise between teeny, and silly money
https://shop.sb-components.co.uk/collections/raspberry-pi-displays/products/7-5inch-hd-e-paper-e-ink-raw-display-880x528-black-white-spi-without-pcb

But I have no idea how to drive it. What *is* an SPI? Ah! Serial
peripheral interface, so it wont be fast. e-ink is alway pretty sluggish
though anyway.

--
"A point of view can be a dangerous luxury when substituted for insight
and understanding".

Marshall McLuhan

David Taylor <david-taylor@blueyonder.co.uk.invalid> wrote:
> On 29/07/2023 09:46, Chris Green wrote:
> > I'm trying to find a display to use with a Pi that will be readable in
> > direct sunlight (on a boat).
> >
> > I can find LCD numeric displays using the Hitachi HD44780 interface
> > and they work OK in the sun but I'm after a graphic display of some
> > sort. It needs to be a reasonable size, so all the 128 x 64 ones are
> > too small really. Something like a 7" display would be ideal.
> >
> > Does anyone here know of anything like this that doesn't cost hundreds
> > of pounds?
>
> Chris,
>
> If an update rate of, say, 30 seconds is adequate, and a 74 mm diagonal is
> adequate, you could look at the Pimoroni Badger - 296 x 128 pixels. Available
> plain, or with embedded wireless:
>
> https://shop.pimoroni.com/products/badger-2040?variant=39752959852627
>
> https://shop.pimoroni.com/products/badger-2040-w?variant=40514062188627
>
> Using two lines of characters it's readable at 2m away. Program with Python -
> many examples and help easily available.
>
No, sadly those E-Ink displays are too slow. I don't need really fast
refresh but I do need to be able to refresh in, say, 100mS (or maybe a
bit more).

--
Chris Green
·

On Sat, 29 Jul 2023 12:08:27 +0100
Chris Green <cl@isbd.net> wrote:

> No, sadly those E-Ink displays are too slow. I don't need really fast
> refresh but I do need to be able to refresh in, say, 100mS (or maybe a
> bit more).

How about this ?

https://www.adafruit.com/product/1303

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/
Host: Beautiful Theory meet Inconvenient Fact
Obit: Beautiful Theory died today of factual inconsistency

Ahem A Rivet's Shot <steveo@eircom.net> wrote:
> On Sat, 29 Jul 2023 12:08:27 +0100
> Chris Green <cl@isbd.net> wrote:
>
> > No, sadly those E-Ink displays are too slow. I don't need really fast
> > refresh but I do need to be able to refresh in, say, 100mS (or maybe a
> > bit more).

Do you need to refresh the whole screen? Many of the e-ink displays are
able to do a partial refresh in much shorter time.

> How about this ?
>
> https://www.adafruit.com/product/1303

The Pixel Qi company went bankrupt in 2015, and while supposedly this one
has the rights to manufacture and claims to do so:
https://www.tripuso.com/index.html
it's not clear if they still do.

However it is possible to buy the 7" panels on Aliexpress:
https://www.aliexpress.com/item/1005001944445301.html
https://www.aliexpress.com/item/4001025242130.html
datasheet
https://www.openvario.org/lib/exe/fetch.php?media=projects:series_00:spec_sheet_pq070ws01_dcn20130103-100.pdf

and it looks like the decoder board used by Adafruit is available:
https://www.aliexpress.com/item/1005003128606387.html
(although the Adafruit 10.1" panel has a different pinout from the Aliexpress
7" one, so a cable would need to be made)

The Adafruit 10.1" panel is also available, for a higher price:
https://www.aliexpress.com/item/32717016812.html

Looking at the datasheet it looks pretty plug and play - you switch from
transmissive through transflective to reflective mode by just dimming the
backlight down to zero. When the ambient light is strong the reflective
pixels wash out the transmissive ones, resulting in semi-greyscale.

The 7" is about 2W in 100% backlight and 0.5W in 0% backlight, so not as low
power as e-ink, but acceptable if you don't need such low power consumption.

Almost tempted to get one to play with, if only I had an application...

Theo

On 29/07/2023 12:08, Chris Green wrote:
> David Taylor <david-taylor@blueyonder.co.uk.invalid> wrote:
>> On 29/07/2023 09:46, Chris Green wrote:
>>> I'm trying to find a display to use with a Pi that will be readable in
>>> direct sunlight (on a boat).
>>>
>>> I can find LCD numeric displays using the Hitachi HD44780 interface
>>> and they work OK in the sun but I'm after a graphic display of some
>>> sort. It needs to be a reasonable size, so all the 128 x 64 ones are
>>> too small really. Something like a 7" display would be ideal.
>>>
>>> Does anyone here know of anything like this that doesn't cost hundreds
>>> of pounds?
>>
>> Chris,
>>
>> If an update rate of, say, 30 seconds is adequate, and a 74 mm diagonal is
>> adequate, you could look at the Pimoroni Badger - 296 x 128 pixels. Available
>> plain, or with embedded wireless:
>>
>> https://shop.pimoroni.com/products/badger-2040?variant=39752959852627
>>
>> https://shop.pimoroni.com/products/badger-2040-w?variant=40514062188627
>>
>> Using two lines of characters it's readable at 2m away. Program with Python -
>> many examples and help easily available.
>>
> No, sadly those E-Ink displays are too slow. I don't need really fast
> refresh but I do need to be able to refresh in, say, 100mS (or maybe a
> bit more).
>
Will they really not do that speed?
Shame, I like e-ink

--
"Women actually are capable of being far more than the feminists will
let them."

On Sat, 29 Jul 2023 17:40:36 +0100
The Natural Philosopher <tnp@invalid.invalid> wrote:

> Will they really not do that speed?
> Shame, I like e-ink

The fastest (E-ink Carta) are around 450ms for a complete refresh
which is OK for turning pages in a book.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/
Host: Beautiful Theory meet Inconvenient Fact
Obit: Beautiful Theory died today of factual inconsistency

On 29/07/2023 18:24, Ahem A Rivet's Shot wrote:
> On Sat, 29 Jul 2023 17:40:36 +0100
> The Natural Philosopher <tnp@invalid.invalid> wrote:
>
>> Will they really not do that speed?
>> Shame, I like e-ink
>
> The fastest (E-ink Carta) are around 450ms for a complete refresh
> which is OK for turning pages in a book.
>
Mmm. But aren't they essentially pixel level addressable, so some smart
software could keep a RAM copy of a small display and only update the
changed pixels?

Not thinking of running videos, y'know!

--
Any fool can believe in principles - and most of them do!

The Natural Philosopher <tnp@invalid.invalid> wrote:
> On 29/07/2023 12:08, Chris Green wrote:
> > David Taylor <david-taylor@blueyonder.co.uk.invalid> wrote:
> >> On 29/07/2023 09:46, Chris Green wrote:
> >>> I'm trying to find a display to use with a Pi that will be readable in
> >>> direct sunlight (on a boat).
> >>>
> >>> I can find LCD numeric displays using the Hitachi HD44780 interface
> >>> and they work OK in the sun but I'm after a graphic display of some
> >>> sort. It needs to be a reasonable size, so all the 128 x 64 ones are
> >>> too small really. Something like a 7" display would be ideal.
> >>>
> >>> Does anyone here know of anything like this that doesn't cost hundreds
> >>> of pounds?
> >>
> >> Chris,
> >>
> >> If an update rate of, say, 30 seconds is adequate, and a 74 mm diagonal is
> >> adequate, you could look at the Pimoroni Badger - 296 x 128 pixels. Available
> >> plain, or with embedded wireless:
> >>
> >> https://shop.pimoroni.com/products/badger-2040?variant=39752959852627
> >>
> >> https://shop.pimoroni.com/products/badger-2040-w?variant=40514062188627
> >>
> >> Using two lines of characters it's readable at 2m away. Program with Python -
> >> many examples and help easily available.
> >>
> > No, sadly those E-Ink displays are too slow. I don't need really fast
> > refresh but I do need to be able to refresh in, say, 100mS (or maybe a
> > bit more).
> >
> Will they really not do that speed?
> Shame, I like e-ink
>
My Kobo reader feels much faster than that, pages turn in what feels
like a (significant) fraction of a second.

--
Chris Green
·

Theo <theom+news@chiark.greenend.org.uk> wrote:
> Ahem A Rivet's Shot <steveo@eircom.net> wrote:
> > On Sat, 29 Jul 2023 12:08:27 +0100
> > Chris Green <cl@isbd.net> wrote:
> >
> > > No, sadly those E-Ink displays are too slow. I don't need really fast
> > > refresh but I do need to be able to refresh in, say, 100mS (or maybe a
> > > bit more).
>
> Do you need to refresh the whole screen? Many of the e-ink displays are
> able to do a partial refresh in much shorter time.
>
No, I don't need to refresh it all. The only relatively fast refresh
is for the rudder position indicator which would just be a single dark
cursor (or similar) moving about.

> > How about this ?
> >
> > https://www.adafruit.com/product/1303
>
> The Pixel Qi company went bankrupt in 2015, and while supposedly this one
> has the rights to manufacture and claims to do so:
> https://www.tripuso.com/index.html
> it's not clear if they still do.
>
> However it is possible to buy the 7" panels on Aliexpress:
> https://www.aliexpress.com/item/1005001944445301.html
> https://www.aliexpress.com/item/4001025242130.html
> datasheet
> https://www.openvario.org/lib/exe/fetch.php?media=projects:series_00:spec_sheet_pq070ws01_dcn20130103-100.pdf
>
>
> and it looks like the decoder board used by Adafruit is available:
> https://www.aliexpress.com/item/1005003128606387.html
> (although the Adafruit 10.1" panel has a different pinout from the Aliexpress
> 7" one, so a cable would need to be made)
>
> The Adafruit 10.1" panel is also available, for a higher price:
> https://www.aliexpress.com/item/32717016812.html
>
> Looking at the datasheet it looks pretty plug and play - you switch from
> transmissive through transflective to reflective mode by just dimming the
> backlight down to zero. When the ambient light is strong the reflective
> pixels wash out the transmissive ones, resulting in semi-greyscale.
>
> The 7" is about 2W in 100% backlight and 0.5W in 0% backlight, so not as low
> power as e-ink, but acceptable if you don't need such low power consumption.
>
> Almost tempted to get one to play with, if only I had an application...
>
Power isn't an issue for me, it's on a canal/river boat with
(relatively) lots of 12 volt power available.

--
Chris Green
·

On Sat, 29 Jul 2023 10:18:46 +0100, The Natural Philosopher
<tnp@invalid.invalid> declaimed the following:

>But I have no idea how to drive it. What *is* an SPI? Ah! Serial
>peripheral interface, so it wont be fast. e-ink is alway pretty sluggish
>though anyway.

SPI is NOT an old-fashioned serial UART. Depending on hardware it can
run at MHz bit rates.
https://raspberrypi.stackexchange.com/questions/699/what-spi-frequencies-does-raspberry-pi-support

On 29/07/2023 19:27, Chris Green wrote:

> No, I don't need to refresh it all. The only relatively fast refresh
> is for the rudder position indicator which would just be a single dark
> cursor (or similar) moving about.
>
I am fairly sure that you can update on a per pixel basis. If you
maintain an in memory copy of what you have *and* what you want, you can
rip through and compare them and only send the updates.

https://www.pervasivedisplays.com/improving-the-e-paper-display-user-experience-using-fast-and-partial-updates/

> Power isn't an issue for me, it's on a canal/river boat with
> (relatively) lots of 12 volt power available.
>
I suggested e-paper because its very good in bright sunlight - less so
in the dark.
Not because of its amazing power consumption.

Personally I think it would do the job, but you would need to code some
fairly low level 'set a pixel, clear a pixel' type stuff. And then build
some graphics libraries on top of that to move your rudder indicator.

A really small one would suit my room thermometer app. Tempting..

--
Any fool can believe in principles - and most of them do!

On a sunny day (Sat, 29 Jul 2023 19:27:46 +0100) it happened Chris Green
<cl@isbd.net> wrote in <2a2gpj-7p752.ln1@esprimo.zbmc.eu>:

>Theo <theom+news@chiark.greenend.org.uk> wrote:
>> Ahem A Rivet's Shot <steveo@eircom.net> wrote:
>> > On Sat, 29 Jul 2023 12:08:27 +0100
>> > Chris Green <cl@isbd.net> wrote:
>> >
>> > > No, sadly those E-Ink displays are too slow. I don't need really fast
>> > > refresh but I do need to be able to refresh in, say, 100mS (or maybe a
>> > > bit more).
>>
>> Do you need to refresh the whole screen? Many of the e-ink displays are
>> able to do a partial refresh in much shorter time.
>>
>No, I don't need to refresh it all. The only relatively fast refresh
>is for the rudder position indicator which would just be a single dark
>cursor (or similar) moving about.

Am I missing something if I propose an old analog meter where the hand shows the rudder position?

Or a needle connected to a stepper motor?

I was into that stuff some years back, used a Pocket book Aqua2 (e-ink display) to connect to
my software server.
https://panteltje.nl/panteltje/xgpspc/index.html
Not that much impressed with e-ink...
There exist very good sunlight readable monitors I have heard.
Do not have a boat at this time...

On 30/07/2023 06:13, Jan Panteltje wrote:

> Am I missing something if I propose an old analog meter where the hand shows the rudder position?
>
> Or a needle connected to a stepper motor?

Rip any dial out of a modern car and replace the fascia. They are all
'digital'

Or use PWM on a model R/C servo.

>
> I was into that stuff some years back, used a Pocket book Aqua2 (e-ink display) to connect to
> my software server.
> https://panteltje.nl/panteltje/xgpspc/index.html
> Not that much impressed with e-ink...
> There exist very good sunlight readable monitors I have heard.
> Do not have a boat at this time...
>

--
Any fool can believe in principles - and most of them do!

Jan Panteltje <alien@comet.invalid> wrote:
> On a sunny day (Sat, 29 Jul 2023 19:27:46 +0100) it happened Chris Green
> <cl@isbd.net> wrote in <2a2gpj-7p752.ln1@esprimo.zbmc.eu>:
>
> >Theo <theom+news@chiark.greenend.org.uk> wrote:
> >> Ahem A Rivet's Shot <steveo@eircom.net> wrote:
> >> > On Sat, 29 Jul 2023 12:08:27 +0100
> >> > Chris Green <cl@isbd.net> wrote:
> >> >
> >> > > No, sadly those E-Ink displays are too slow. I don't need really fast
> >> > > refresh but I do need to be able to refresh in, say, 100mS (or maybe a
> >> > > bit more).
> >>
> >> Do you need to refresh the whole screen? Many of the e-ink displays are
> >> able to do a partial refresh in much shorter time.
> >>
> >No, I don't need to refresh it all. The only relatively fast refresh
> >is for the rudder position indicator which would just be a single dark
> >cursor (or similar) moving about.
>
> Am I missing something if I propose an old analog meter where the hand shows the rudder position?
>
No, it's an approach that I'm seriously considering. As the
'transducer' at the rudder end is simply a pot stuck on top of the
rudder post the whole thing can be analogue. I'm actually thinking
that an edgewise meter might be best.

--
Chris Green
·

On 30/07/2023 10:55, Chris Green wrote:
> Jan Panteltje <alien@comet.invalid> wrote:
>> On a sunny day (Sat, 29 Jul 2023 19:27:46 +0100) it happened Chris Green
>> <cl@isbd.net> wrote in <2a2gpj-7p752.ln1@esprimo.zbmc.eu>:
>>
>>> Theo <theom+news@chiark.greenend.org.uk> wrote:
>>>> Ahem A Rivet's Shot <steveo@eircom.net> wrote:
>>>>> On Sat, 29 Jul 2023 12:08:27 +0100
>>>>> Chris Green <cl@isbd.net> wrote:
>>>>>
>>>>>> No, sadly those E-Ink displays are too slow. I don't need really fast
>>>>>> refresh but I do need to be able to refresh in, say, 100mS (or maybe a
>>>>>> bit more).
>>>>
>>>> Do you need to refresh the whole screen? Many of the e-ink displays are
>>>> able to do a partial refresh in much shorter time.
>>>>
>>> No, I don't need to refresh it all. The only relatively fast refresh
>>> is for the rudder position indicator which would just be a single dark
>>> cursor (or similar) moving about.
>>
>> Am I missing something if I propose an old analog meter where the hand shows the rudder position?
>>
> No, it's an approach that I'm seriously considering. As the
> 'transducer' at the rudder end is simply a pot stuck on top of the
> rudder post the whole thing can be analogue. I'm actually thinking
> that an edgewise meter might be best.
>

If you decide to use e.g. a radio control servo, there are very
inexpensive 'servo testers' which do in fact have a pot in the middle.
The whole lot could be had for just a few dollars. You could wire your
pot up to them. Or generate your own PWM with a pi - the servo spec is a
20 Hz (or thereabouts) repetition of a 1-2ms pulse, with 1.5ms being the
putative 'straight ahead' position.

And every time the servos dies its trivial money these days to plug in a
new one

Analogue meters don't come cheap or with suitable scales these days. And
thay are soewahtt fragile.

--
When plunder becomes a way of life for a group of men in a society, over
the course of time they create for themselves a legal system that
authorizes it and a moral code that glorifies it.

Frédéric Bastiat

On a sunny day (Mon, 31 Jul 2023 10:38:29 +0100) it happened The Natural
Philosopher <tnp@invalid.invalid> wrote in <ua7vem$388st$1@dont-email.me>:

>On 30/07/2023 10:55, Chris Green wrote:
>> Jan Panteltje <alien@comet.invalid> wrote:
>>> On a sunny day (Sat, 29 Jul 2023 19:27:46 +0100) it happened Chris Green
>>> <cl@isbd.net> wrote in <2a2gpj-7p752.ln1@esprimo.zbmc.eu>:
>>>
>>>> Theo <theom+news@chiark.greenend.org.uk> wrote:
>>>>> Ahem A Rivet's Shot <steveo@eircom.net> wrote:
>>>>>> On Sat, 29 Jul 2023 12:08:27 +0100
>>>>>> Chris Green <cl@isbd.net> wrote:
>>>>>>
>>>>>>> No, sadly those E-Ink displays are too slow. I don't need really fast
>>>>>>> refresh but I do need to be able to refresh in, say, 100mS (or maybe a
>>>>>>> bit more).
>>>>>
>>>>> Do you need to refresh the whole screen? Many of the e-ink displays are
>>>>> able to do a partial refresh in much shorter time.
>>>>>
>>>> No, I don't need to refresh it all. The only relatively fast refresh
>>>> is for the rudder position indicator which would just be a single dark
>>>> cursor (or similar) moving about.
>>>
>>> Am I missing something if I propose an old analog meter where the hand shows the rudder position?
>>>
>> No, it's an approach that I'm seriously considering. As the
>> 'transducer' at the rudder end is simply a pot stuck on top of the
>> rudder post the whole thing can be analogue. I'm actually thinking
>> that an edgewise meter might be best.
>>
>
>If you decide to use e.g. a radio control servo, there are very
>inexpensive 'servo testers' which do in fact have a pot in the middle.
>The whole lot could be had for just a few dollars. You could wire your
>pot up to them. Or generate your own PWM with a pi - the servo spec is a
>20 Hz (or thereabouts) repetition of a 1-2ms pulse, with 1.5ms being the
>putative 'straight ahead' position.
>
>
>And every time the servos dies its trivial money these days to plug in a
>new one
>
>Analogue meters don't come cheap or with suitable scales these days. And
>thay are soewahtt fragile.

I still have some nice big analog one...
Those servos are indeed cool,
http://panteltje.nl/pub/spare_servo_img_1559.jpg
http://panteltje.nl/panteltje/raspberry_pi_satellite_tracker/
I have played with those servos a lot:
http://panteltje.nl/pub/horizontal_IR_target_tracking_4686.avi
for all sort of things
Use a Raspberry Pi to control a Microchip 18F14K22 to drive a camera positioner...
https://panteltje.nl/panteltje/pic/camc_pic/
But some of my security cams already have x,y movement...
wrote some Linux code to control those too, if anyone wants it I can publish it.

On 29/07/2023 10:18, The Natural Philosopher wrote:
> But I have no idea how to drive it. What *is* an SPI? Ah! Serial
> peripheral interface, so it wont be fast. e-ink is alway pretty sluggish
> though anyway.

It's not an old RS232 port! SPI is clocked up to 250MHz, and it's used
to drive many types of display on the Pi, including LCD and OLED, which
are much quicker that e-ink.

---druck

On Mon, 31 Jul 2023 10:07:57 GMT, Jan Panteltje wrote:

>>If you decide to use e.g. a radio control servo, there are very
>>inexpensive 'servo testers' which do in fact have a pot in the middle.
>>The whole lot could be had for just a few dollars. You could wire your
>>pot up to them. Or generate your own PWM with a pi - the servo spec is a
>>20 Hz (or thereabouts) repetition of a 1-2ms pulse, with 1.5ms being the
>>putative 'straight ahead' position.
>
If you want to use a servo to move a nice, big rudder position indicator,
another low-cost option is to use a PICAXE device to drive the servo.

The PICAXE-08M2 is a simple, cheap 8-pin DIP package with a serial port
that's used both to load programs, which are written in a simple integer
compiled BASIC, and to accept ASCII strings containing textual commands
and/or integer values. All PICAXE models have built-in firm-ware to drive
radio control servos. There are bigger chips, i.e. have more i/o pins, but
those are likely to be overkill for this application.

The BASIC compiler/downloader can be run on an RPi, though you'll also
need a PICAXE USB Download Cable £14.99 inc. VAT, though most users only
need one of these: it connects to an RPi USB socket and has a 3.5mm coax
jack at the PICAXE end.

They also sell prototyping boards with a 3.5mm socket: an RPi, BASIC
compiler, prototyping board and download cable forms a fairly complete
development and prototyping outfit.

Full details and prices are here: https://www.picaxestore.com/

--

Martin | martin at
Gregorie | gregorie dot org

The Natural Philosopher <tnp@invalid.invalid> wrote:
> Analogue meters don't come cheap or with suitable scales these days.

Unless you go to hamfests, in which case you can usually buy great
quality old ones for $5 or less. Ebay seems to have cheap Chinese
ones in the $5-$10 range too.

> And thay are soewahtt fragile.

Well they _might_ not survive being dropped on the floor, but then
neither might a Raspberry Pi board.

--
__ __
#_ < |\| |< _#