I have been experimenting with ESP32 and RPi camera modules to record video and pictures as well as log events in log files. While cameras typically demand 100-150 mA,, the boards themselves can make due with ~80mA and can be put to sleep to consume less power when nothing is happening.

Since the ESP32 is less power-hungry than an RPi I will use one to make a simple event logger that is accessible over wifi and bluetooth so experimenters will have an easy way to monitor activity without video. The parts to do this with an ESP32 cost about 10EUR.

This would also make it more practical to run the vending machine off of batteries/solar and allow remote log collection via the internet, internal network, or when in proximity of bluetooth.

After looking more into it I could use an ESP32 and provide the ability to monitor, get logs, do some simple graphing, configure and control the vending machine via wifi or bluetooth using just a few additional parts. I could even integrate one of the ESP32 CAM modules without more wires. Even with an ESP32 dev board and an ESP32 CAM board, all the electronic components (there would be a lot less of them) would cost ~25 EUR.

This would be a big shift away for the current all-analog approach, but since ESP32 boards are pretty inexpensive, have radios, have lots of GPIO and are not too difficult to program I think this would make this project much more functional and more attractive to people that just want to use the thing without spending an hour or so soldering.