Feb 20, 2013


This IR remote extender can increase the range of most simple IR remotes (those operating on a 40KHz modulation) a significant distance. In use, the remote is pointed toward the detector on the circuit, and a button is pressed. The Sharp IR detector then decodes the 40KHz modulated signal into a series of pulses, which trigger a 555 timer. The 555 outputs pulses which are re-modulated and used to drive an IR LED. The circuit is excellent for use in a large room like a presentation hall where a typical IR remote is a bit weak. By extending the wires to the output LED (using shielded cable) you can control a device where line of sight isn't available (such as a wall full of TVs in another room). 


Total Qty.
R1, R6210K 1/4W Resistor
R211K 1/4W Resistor
R3110K Linear Pot
R412.2K 1/4W Resistor
R5147 Ohm 1/4W Resistor
C110.01uF Ceramic Disc Capacitor
Q1, Q222N3904 NPN Transistor
D11IR LEDRadio Shack 276 143C
U11GP1U52X IR Module
U21TLC555 CMOS TimerLMC555, 7555
MISC1Board, Sockets For U2, Wire


  1. Only the CMOS TLC555 timer can be used in this circuit. The original NE555 cannot operate reliably at 40KHz. Acceptable substitutions are shown in the parts list.
  2. Almost all powerful IR LEDs can be used for D1 if the appropriate value of R5 is chosen.
  3. To calibrate the circuit, use a frequency counter. Connect it in parallel with D1 and then ground the base of Q1. Adjust R3 for 40KHz on the counter. If a counter is not available, you will just have to point a remote at the circuit, press a button, and then adjust R3 until it works. This can take a few tries as not all remotes transmit continuously.
  4. If you intend to remotely mount D1 any great distance, you will need to use shielded cable. Connect the shield to circuit ground.

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