LPTEL is a phone ringer repeater: it turns on a light bulb when the phone is ringing. It connects to the telephone line, so it is independent of the telephone. Phone ringer repeater, R1 components – resistor 47 ohms 1/4 WC1 – [...]
STROBO is the project of a xenon strobe lamp, which I made when I was a boy. The lamp can flash independently, at a setable frequency, and moreover it can also be controlled from the PC, a microphone and other lights, through modules [...]
SPTEL is a busy phone line detector, which I designed when I was just over 15 years old: it is an LED that lights up when the phone line is engaged by a telephone in conversation. This my [...]