Hello!
I’m doing soil sampling with wintex 1000 and for navigation I use QField.
At the moment I manually add points where I take samples, but I want to automate this. Since wintex 1000 has a free wire for ‘gps’ each time a sample is taken, a 12v impulse to the wire is given.
What possible solution could I make/do to add a device to the wire which would give signal to QField and so it adds a point at current location?
This is a tricky one. 
hello and welcome @Eduards_Vanags
My first guest would be to try and send a “Volume Up” signal to QField, since that’s a default button for adding features.
This obviously depends on your device’s capabilities, and most likely would involve some wiring/soldering/tinkering. I haven’t tried this myself, but maybe sending a “volume up” signal through a bluetooth device, such as a keyboard, also might trigger the Add Feature function? If so, maybe you can wire that 12v signal to an Arduino compatible board, such as one based on a ESP32 chip (which has bluetooth capabilites). Another option might be to try and use one of those cheap bluetooth remotes that come with selfie sticks (again, I’m not sure that would trigger a Add Feature event on QField, but it’s worth a try).
well, just tried it and QField pops the Add Feature form with both a bluetooth and a wired keyboard connected to an android phone (when pressing the Volume Up key or macro).
This means that you can also build a circuit with a non-bluetooth microcontroller, but with one that can emulate a USB-compliant keyboard. Some options are the Raspberry pico (RP2040, I believe…) or the ATmega32u4 (such as in the Arduino Pro Micro or Leonardo)
So youre saying avoid sensor option in qfield and just make a volume up trigger? This sounds like something possible. Now i know, what direction I can look, thank you!