Activating the built-in auxiliary heater via the input contact

Hello everyone!

I have the original factory-installed auxiliary heating system in my Audi A4/8E/B7. Okay, I've now purchased a Webasto Thermocall GSM module and I need the following:

The GSM module has the following outputs: 1. W-Bus, 2. Power-on contact 12V (voltage is present during the entire operation). (Heating duration)

I need a circuit that sends an 'on' command to the STH via the CAN bus when the input voltage is 12V, and sends an 'off' command when the voltage is 0V.

'This way, I can control my STH using the GSM module.'

Who knows what?? ................

If you have actually installed a genuine auxiliary heater (not just a pre-heater), then you can connect to it using the W-bus system.
It works perfectly without any issues.

Best regards,
Maxx.

Thank you for the hint.

'However, my Audi doesn't have a Thermotop installed, but rather an Eberspächer Nordic AB - 8E0 241 141 F with an Audi control unit 8E0 909 509 J.'
'I only have the GSM module from Webasto. There is no way to control the heater except through the FIS menu. As far as I know, there is no connection option for a 12V signal other than through the R64 radio receiver input.' Upon being turned on, the radio receiver sends a rectangular signal to the control unit, and upon being turned off, it sends a one-way rectified signal.
However, the range is too unreliable for me; GSM, on the other hand, always works. I was actually thinking about disassembling the transmitter and integrating it into the GSM module.
A CAN bus control system would, of course, be even better.
It should be simple if the GSM module provides 12V, to implement a power-on or... To send a shutdown command.

Sure, here's the translation:

'LG' translates to 'Best regards' or 'Sincerely' in English.

Mario.

Okay, I understand. Eberspächer has its own unique story.
Then it would be easier to write a converter that transforms the 12V signal from the GSM receiver into the R64 signal.
To do that, you need to know exactly what the signal from the R64 looks like.
The best way to measure this is with an oscilloscope, and then post the results here.
This implementation can definitely be done with an ATTiny13 or something similar.

Best regards,
Maxx.

Hello,

Okay, here you can see the oscilloscope display.
[power-on signal.JPG]
[power_off_signal.JPG]


However, I will integrate the electronics of a handheld transmitter with a GSM module, and use reed relays to control the on/off button.
Then, it might even be possible to pair another remote control. You can then either call the GSM module or use the second remote control to operate the system. I think it's simpler.

Thank you.

Best regards,
Mario

Hello Mario,

The signal could be processed using a microcontroller.
Your idea about the remote control also has its merits.
The second remote control would be a good solution for that.

Best regards,
Maxx.

Hello,

I came across this forum while searching for a solution, and I have the following question.

Were the posted images of the power-on and power-off signals taken with the auxiliary heater connected and running?

I'm experiencing a similar problem, but in my case, the control unit number of the receiver is 8E0 909 509. Unfortunately, the original Facebook post is no longer available.

The question regarding the connected auxiliary heater arises from the need to ensure that the heating unit itself is not still sending a signal to the wireless receiver (as with the W-bus system), which, in the absence of a signal, would cause the heating unit to switch off again.

I want to replicate the signals in order to connect a GSM module.

See you soon, and thank you.

Hello,

Okay, here you can see the oscilloscope display.



Unfortunately, I can no longer see the oscilloscope display!
I need help.

Hello,

Unfortunately, the files cannot be found; it's likely that they were linked externally rather than uploaded.

Best regards, Rainer.