Power Module 3
An "Arduino Nano 33 BLE Sense" shield that...
- Supplies 5V (V+ pins) from a TSP61220 step-up converter,
- This voltage also powers the Arduino
- Supplies 2.5V (Vref pins) from a voltage divider + LM321 opamp,
- Is powered by a 1.2V AAA battery on "Keystone 82" battery clips,
- Exposes 3 digital and 8 analog pass-through pins for the Arduino
- Provides jumpers for
- Enabling the reference voltage circuit
- Connecting Arduino's A7 to the + terminal of the battery to measure the battery level
- Two software-configurable pins that you can ground with a jumper
- Dimensions: 47.63 x 31.34mm
Improvements over Power Module 2
- Placed the arduino and battery side-by-side instead of on top of each other. This makes the board wider and less tall, making it fit better on the forearm.
- Added more capacitors all over the place
- Added various jumpers:
- A solder jumper to enable/disable the reference voltage generator, in case I come up with a setup where I won't actually need it
- A solder jumper to sacrifice one electrode and use its analog input pin to measure the battery charge instead.
- Three configuration pins, connectable via jumpers, to change software settings on the fly and toggle between up to 4 different modes. Or you can use them to plug in an extra module.
- Hopefully fixed the layout for the step-up converter