40khz IR tester:
40khz IR tester

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.