What a plant can power
Honest numbers, and why they are enough.
Start with the physics. Published experiments with plant microbial fuel cells report sustained power on the order of tens of milliwatts per square metre of planted soil, at a few hundred millivolts per cell.
That will not charge a phone. It will never run a data centre, and anyone who tells you otherwise is selling something.
But a modern microcontroller asleep draws only microwatts, and a small neural network on such a chip can finish an inference in tens of microjoules. Twenty milliwatts is twenty thousand microjoules every second.
So the budget is real, as long as you spend it carefully. Thinking is cheap; talking is expensive. The radio costs far more than the model, which gives us our design rule: think locally, speak rarely, and send conclusions instead of raw data.
Prototype I exists to replace these literature numbers with our own. We will publish them here.