Mushroom Music

[mascail]

Hey, I want to use my Teensy 4.0 to read bioelectric signals from a mushroom or plant.

For this I want to use two subdermal electrodes (which penetrate the mushroom/plant) to measure difference in electric potential (voltage). Extremely low voltage is expected (around 0.03 to 2.1 mV [source: https://royalsocietypublishing.org/doi/10.1098/rsos.211926]) and I was wondering how I could go about reading this? Do I need anything else besides the Teensy board with its built in ADC? For starters I would plug both electrodes into analog pins 0 and 1, use the analogRead function and then substract both values?

 

[MarkT]

No, those signals are way too small to be fed direct to the ADC and get anything meaningful out.

An instrumentation amp is probably the way to go, though you'd need to ensure the potentials fall within its input voltage range.
Sounds like you need a gain around 1000 or so, with precision, low drift, and differential signal - exactly what an
instrumentation amp is designed for in fact.

Note that the T4's are strictly 0V--3.3V only, so some protection on the ADC input pin may be needed. However I think you
can be all 3.3V if you pick the HX711, which also has a lot of Arduino ecosystem support.