Symmetry Optical Keyboard
| tr | tf | unit | |
| pt | 18 | 5 | us |
The speed of optical switch depends on the speed of finger, the shortest time for finger to press a switch is about 200 us, but usually it takes a few milliseconds. Test on mcu’s adc at f_adc = 12MHz, f_s = 12 / 14 MHz, resolution = 12 bits. Get the average of the five.