555 Timer 40khz Ir 1c20z

555 timer 40khz IR:

parts: U1

555 Timer IC

R1

47 ohm resistor

R2

470 ohm resistor

R3

5k variable resistor

C1

0.0047uf ceramic capacitor

LED1,LED2

Infrared LED's

This circuit oscillates two infrared LED's at 40 khz. To make sure it is transmitting IR light, you can get a little tool from radio shack for about $5. It is a small sheet of plastic about 1" by 3" with a special strip of material, that when exposed to IR light glows (it's actually kinda cool..) A way to check for 40khz IR light is to build a circuit that lights an led when 40khz light is detected. You can get the schematic by clicking here. http://www.reconnsworld.com/ir_ultrasonic_555timer40khzir.html

40khz IR tester:

parts: R1

270 ohm resistor

L1

Visible LED

S1

On/Off Switch

IR Module

Sharp GP1U5X IR Detect Module (or  compatible)

Use this circuit to test if the light coming from your 40khz IR emitter is really emitting the right frequency. The schematic says to use a GP1U5X ir module, but probably any 40khz detector module will work.. I used a GP1U26X module.