Webcam (Experimental)
If you don't have a Yocto or Metrix volmetre, you can use a voltmeter of your choice. In this case your volmeter must have a good quality screen, backlit if possible. You will then have to use a webcam to film the screen of the volmeter. An artificial intelligence algorithm will then digitize the content of the voltmeter screen to go from an image to a usable number.
Using Advice
Webcam
The process of digitalisation required a quality FHD webcam, by example the Logitech Brio webcam, or a webcam with minimum the same quality. Note that, the Logitech Brio webcam can work in low light (with a HDR mode) and own an autofocus wich allow to put the wecam near of the voltmetre screen.
Voltmetre
To increase the digitalistaion quality, use a multimeter wich own a background light in the display. In the settings, fend for yourself to keep the light as long as possible.
Setup
It is strongly recommended to put a cardboard box above the optical setup to avoid the reflections of parasitic light sources, and keep constant and homogeneous ligthing conditions. It may also be useful to stick a transparent anti-reflective sticker on the volmeter screen.
Warning
This process is experimental and being improved. Currently, it does not give a 100% success rate, which is necessary for the software DiscoveryMat.