Electronic – Health risks of exposed contact to a capacitive sensor


I want to make a wearable metal trinket with the ATtiny85 chip acting as a capacitive sensor (with the same technique that this Arduino library uses), so it can detect when it's being worn.

Are there any health risks to touching what is effectively a low-voltage live wire for an arbitrarily long amount of time?

Here's the schematic from that link:

Capacitive sensor schematic

Be patient please, I'm a beginner 🙂

Best Answer

Yes, there may be a risk for long term wear. If your electrodes have an ohmic contact with the patient, and they have a DC bias, and they are made of a reactive metal like copper, then you may be generating metal ions on the patient's skin. Metal ions may cause a chemical burn.

I have an 8 year old scar to illustrate this. For a few days, I was experimenting with an EKG circuit and I used makeshift copper electrodes. The burns (two more: on another arm and on a foot) took a month to heal.

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