This basically Prototype 8 with minor bug fixes, higher amplification gain, an optional power LED, and easier assembly. See its description for more information.
Changes to Prototype 9:
- Increased amplification gain on electrode modules from x51 to x501. This increases the signal-to-noise ratio significantly.
- Reduced amplification gain of Signal 2 by half, compared to the other signals. (x251 compared to x501.) This compensates for a signal interference problem on the out2 trace of the electrode module PCB.