While building a Toastmaster timer, I needed a switch to act as a Start/Stop switch. I first built it with a long flexible coax cable, but as time went on, it turned out to be impracticable: it could be too long and people could trip on it. So I was looking for a circuit to remotely control the timer without wire, and it almost has to be cheap and built from readily available household components. Let's see what do I have around my house which can function as a wireless device. Eureka! a bunch of old and abandoned IR remote controls.
The idea is very simple: the IR remote control sends out a stream of 10 bits, and the simplest way so far to convert this stream to a simple pulse is using an One shot circuit to generate a simple pulse when any remote button is pushed.
Step 1: Component list
Very short: 2 IC and 4 passive elements.
555 (8 pin)
TSOP1838 (Vishay IR receiver 38Khz)
Caps: 10uF, 1uF, 0.1uF
Step 2: Schematic
Schematic and a remote control
Step 4: Scope shot
Blue trace: actual IR code
Yellow trace: output of the 555: single pulse