IR UART

After correcting the timing RC network and the IR receiver power supply filter, I'm happy with the performance of the modules, at least judging by the transmission and reception of 1 kHz test signal. The pulse frequency is near the target 57.6 kHz and the signal from the receiver is sharp and high.

Right after the assembly, a basic test confirms the modules work, though the pulse generator frequency is somewhat off. Replacing a 6.8 kΩ resistor with a 4.7 kΩ should fix this.

When one module is fed with the 1 kHz signal (from the oscilloscope reference generator), the other receives the signal with a slight delay (as expected).

Funny that the practical formula for the pulse generator frequency is f = 1 / (3.14 * R * C), not f = 1 / (2.197 * R * C), as advertised in the source. Some early π-day interference here!