This circuit for low frequency data transmission was found in the May 1977 issue of Radio Electronics magazine. The circuit modulates the signal at two frequencies for bits 0 and 1.
Photoelectric cells can be used as sensitive light sensors. However, the low voltage they generate...
With the illustrated circuit we can run a DC motor in one direction or the other, depending on...
In this circuit the relay triggers on when light falls onto the sensor, a common LDR. Power supply...