Outside view, the metal from the MQ4 detector is electrically isolated from the rest:
https://www.imagebam.com/view/MEPUSBC

Bit crowded in there, switcher to 5V, parts just what I found laying about:
https://www.imagebam.com/view/MEPUSGL

There is also a BD137 emitter follower hidden under the ethernet module to make 3.3 V for the PIC and ethernet module from the 5 V.
I modified the ethernet connecter and cut the traces that did put a resistor over the POE power lines.
Thing gets slightly warm, that MQ4 detector has actually a light bulb like filament.
On 12V it glows in the dark, one actually survived that 12 V (5 V is the nominal voltage)! Sensitivity is then damaged.

I am testing free anonymous (no registering) upload site imagebam.com, seems to work OK.

Circuit diagram:
https://www.imagebam.com/view/MEPUSJB

The C code was already published here last week.

So it basically every few seconds sends UDP packets to 192.168.178.73 containing sensor current, gas concentration, and error messages
(broken MQ4 filament, high gas level),

The receiving end processes that data and forwards the data via UDP to 192.168.178.95 that analyses the data and gives voice messages
via the local sound system, so no stupid beeps, could even work remote if needed.
It also gives alarm if no sensor messages received for some time.

On 02/11/2023 5:19 am, Jan Panteltje wrote:
> Outside view, the metal from the MQ4 detector is electrically isolated from the rest:
> https://www.imagebam.com/view/MEPUSBC
>
> Bit crowded in there, switcher to 5V, parts just what I found laying about:
> https://www.imagebam.com/view/MEPUSGL
>
> There is also a BD137 emitter follower hidden under the ethernet module to make 3.3 V for the PIC and ethernet module from the 5 V.
> I modified the ethernet connecter and cut the traces that did put a resistor over the POE power lines.
> Thing gets slightly warm, that MQ4 detector has actually a light bulb like filament.
> On 12V it glows in the dark, one actually survived that 12 V (5 V is the nominal voltage)! Sensitivity is then damaged.
>
> I am testing free anonymous (no registering) upload site imagebam.com, seems to work OK.
>
> Circuit diagram:
> https://www.imagebam.com/view/MEPUSJB
>
>
> The C code was already published here last week.
>
> So it basically every few seconds sends UDP packets to 192.168.178.73 containing sensor current, gas concentration, and error messages
> (broken MQ4 filament, high gas level),
>
> The receiving end processes that data and forwards the data via UDP to 192.168.178.95 that analyses the data and gives voice messages
> via the local sound system, so no stupid beeps, could even work remote if needed.
> It also gives alarm if no sensor messages received for some time.
>
>
>
>
>

imagebam doesn't load for me?

piglet

On a sunny day (Thu, 2 Nov 2023 14:23:39 +0000) it happened piglet
<erichpwagner@hotmail.com> wrote in <ui0bdd$27sbs$1@dont-email.me>:

>On 02/11/2023 5:19 am, Jan Panteltje wrote:
>> Outside view, the metal from the MQ4 detector is electrically isolated from the rest:
>> https://www.imagebam.com/view/MEPUSBC
>>
>> Bit crowded in there, switcher to 5V, parts just what I found laying about:
>> https://www.imagebam.com/view/MEPUSGL
>>
>> There is also a BD137 emitter follower hidden under the ethernet module to make 3.3 V for the PIC and ethernet module from the
>> 5 V.
>> I modified the ethernet connecter and cut the traces that did put a resistor over the POE power lines.
>> Thing gets slightly warm, that MQ4 detector has actually a light bulb like filament.
>> On 12V it glows in the dark, one actually survived that 12 V (5 V is the nominal voltage)! Sensitivity is then damaged.
>>
>> I am testing free anonymous (no registering) upload site imagebam.com, seems to work OK.
>>
>> Circuit diagram:
>> https://www.imagebam.com/view/MEPUSJB
>>
>>
>> The C code was already published here last week.
>>
>> So it basically every few seconds sends UDP packets to 192.168.178.73 containing sensor current, gas concentration, and error
>> messages
>> (broken MQ4 filament, high gas level),
>>
>> The receiving end processes that data and forwards the data via UDP to 192.168.178.95 that analyses the data and gives voice
>> messages
>> via the local sound system, so no stupid beeps, could even work remote if needed.
>> It also gives alarm if no sensor messages received for some time.
>>
>>
>>
>>
>>
>
>imagebam doesn't load for me?

Just tried it again from an other browser (ow chromium) and and other IP addres, no problem.
Anybody else problems?
May put it on my website later.

On Wednesday, November 1, 2023 at 10:19:11 PM UTC-7, Jan Panteltje wrote:
> Outside view, the metal from the MQ4 detector is electrically isolated from the rest:
> https://www.imagebam.com/view/MEPUSBC
>
> Bit crowded in there, switcher to 5V, parts just what I found laying about:

Excellent! For the market for something like that, something using pi pico-W with a
wall tumor power supply would be slightly easier to install, and document.
The use of real wired POE Ethernet is still a bit of a barrier (how, I wonder, would I get
that to the vicinity of my furnace?).

> The receiving end processes that data and forwards the data via UDP to 192.168.178.95 that analyses the data and gives voice messages
> via the local sound system, so no stupid beeps, could even work remote if needed.
> It also gives alarm if no sensor messages received for some time.

That's a good feature set. I really like the absolute IP addressing, even if it's nonrouting; it's
not dependent on DHCP service, just requires some note-taking to survive when your
net gets new nodes. I've had reconfiguration (loses the printer, test area needs a fresh
network config every time we power down) issues with addressing. Fixed addressing
and IP6 together ought to make the internet of things workable.

On a sunny day (Thu, 2 Nov 2023 14:23:39 +0000) it happened piglet
<erichpwagner@hotmail.com> wrote in <ui0bdd$27sbs$1@dont-email.me>:

>On 02/11/2023 5:19 am, Jan Panteltje wrote:
>> Outside view, the metal from the MQ4 detector is electrically isolated from the rest:
>> https://www.imagebam.com/view/MEPUSBC
>>
>> Bit crowded in there, switcher to 5V, parts just what I found laying about:
>> https://www.imagebam.com/view/MEPUSGL
>>
>> There is also a BD137 emitter follower hidden under the ethernet module to make 3.3 V for the PIC and ethernet module from the
>> 5 V.
>> I modified the ethernet connecter and cut the traces that did put a resistor over the POE power lines.
>> Thing gets slightly warm, that MQ4 detector has actually a light bulb like filament.
>> On 12V it glows in the dark, one actually survived that 12 V (5 V is the nominal voltage)! Sensitivity is then damaged.
>>
>> I am testing free anonymous (no registering) upload site imagebam.com, seems to work OK.
>>
>> Circuit diagram:
>> https://www.imagebam.com/view/MEPUSJB
>>
>>
>> The C code was already published here last week.
>>
>> So it basically every few seconds sends UDP packets to 192.168.178.73 containing sensor current, gas concentration, and error
>> messages
>> (broken MQ4 filament, high gas level),
>>
>> The receiving end processes that data and forwards the data via UDP to 192.168.178.95 that analyses the data and gives voice
>> messages
>> via the local sound system, so no stupid beeps, could even work remote if needed.
>> It also gives alarm if no sensor messages received for some time.
>>
>>
>>
>>
>>
>
>imagebam doesn't load for me?

Just tried it again from an other browser (ow chromium) and and other IP addres, no problem.
Anybody else problems?
May put it on my website later.

MQ4 gas sensor circuit diagram, asm code, C code and pictures all in one .tgz file for download at my website:
Webbrowser to
panteltje.nl/pub/gas_pic_udp-0.1.tgz

or simply
wget panteltje.nl/pub/gas_pic_udp-0.1.tgz

All code GPL

On a sunny day (Thu, 02 Nov 2023 15:10:27 GMT) it happened Jan Panteltje
<alien@comet.invalid> wrote in <ui0e53$10upn$1@solani.org>:

>On a sunny day (Thu, 2 Nov 2023 14:23:39 +0000) it happened piglet
><erichpwagner@hotmail.com> wrote in <ui0bdd$27sbs$1@dont-email.me>:
>
>>On 02/11/2023 5:19 am, Jan Panteltje wrote:
>>> Outside view, the metal from the MQ4 detector is electrically isolated from the rest:
>>> https://www.imagebam.com/view/MEPUSBC
>>>
>>> Bit crowded in there, switcher to 5V, parts just what I found laying about:
>>> https://www.imagebam.com/view/MEPUSGL
>>>
>>> There is also a BD137 emitter follower hidden under the ethernet module to make 3.3 V for the PIC and ethernet module from
>>> the
>>> 5 V.
>>> I modified the ethernet connecter and cut the traces that did put a resistor over the POE power lines.
>>> Thing gets slightly warm, that MQ4 detector has actually a light bulb like filament.
>>> On 12V it glows in the dark, one actually survived that 12 V (5 V is the nominal voltage)! Sensitivity is then damaged.
>>>
>>> I am testing free anonymous (no registering) upload site imagebam.com, seems to work OK.
>>>
>>> Circuit diagram:
>>> https://www.imagebam.com/view/MEPUSJB
>>>
>>>
>>> The C code was already published here last week.
>>>
>>> So it basically every few seconds sends UDP packets to 192.168.178.73 containing sensor current, gas concentration, and
>>> error
>>> messages
>>> (broken MQ4 filament, high gas level),
>>>
>>> The receiving end processes that data and forwards the data via UDP to 192.168.178.95 that analyses the data and gives voice
>>> messages
>>> via the local sound system, so no stupid beeps, could even work remote if needed.
>>> It also gives alarm if no sensor messages received for some time.
>>>
>>>
>>>
>>>
>>>
>>
>>imagebam doesn't load for me?

PS
uploaded it all as .tgz to my website:
panteltje.nl/pub/gas_pic_udp-0.1.tgz

Untar:
tar -zxvf gas_pic_udp-0.1.tgz

On 11/2/2023 11:10 AM, Jan Panteltje wrote:
[...]
>>
>> imagebam doesn't load for me?
>
> Just tried it again from an other browser (ow chromium) and and other IP addres, no problem.
> Anybody else problems?
>

It does load, but ... so slowly that I didn't wait for it.