Infa-Red Remote Control

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I have received a number of emails requesting schematics for infa-red remotes. So here is one. This remote transmits a tone using an infa-red LED. This tone is decoded by the receiver. Since the receiver only switches when it "hears" the tone, there are no accidental activations.

Schematic For Transmitter

This is the schematic of the IR Transmitter

Schematic For Receiver

This is the schematic for the IR Receiver


Total Qty.
R1122K 1/4W Resistor
R211 Meg 1/4W Resistor
R311K 1/4W Resistor
R4, R52100K 1/4W Resistor
R6150K Pot
C1, C220.01uF 16V Ceramic Disk Capacitor
C31100pF 16V Ceramic Disk Capacitor
C410.047uF 16V Ceramic Disk Capacitor
C510.1uF 16V Ceramic Disk Capacitor
C613.3uF 16V Electrolytic Capacitor
C711.5uF 16V Electrolytic Capacitor
Q112N2222 NPN Silicon Transistor2N3904
Q212N2907 PNP Silicon Transistor
Q31NPN Phototransistor
D111N914 Silicon Diode
IC11LM308 Op Amp IC
IC21LM567 Tone Decoder
LED11Infa-Red LED
RELAY16 Volt Relay
S11SPST Push Button Switch
B113 Volt BatteryTwo 1.5V batteries in series
MISC1Board, Sockets For ICs, Knob For R6, Battery Holder
RELAY16 Volt Relay


  1. To adjust the circuit, hold down S1 while pointing LED1 at the receiver. Adjust R6 until you hear the relay click.
  2. You can increase range by using a high output LED for LED1.
  3. Bright light will stop the receiver from responding to the transmitter.
  4. There is an error in the schematic. There shuold be a 1 megaohm resistor between pin 3 of IC1 and ground. This provides a 0 volt reference to bias the IC.

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Infa-Red Remote Control
Thursday, December 27, 2012 10:12:07 PM
How long is the range of IR transmitter can afford? Should I put the transmitter and receiver in a dark place? Thanks
Infa-Red Remote Control
Tuesday, February 28, 2012 3:09:39 AM
oh........dont waste your time...its fake
Infa-Red Remote Control
Friday, November 25, 2011 11:09:18 PM
Sine input & output to IC1 is capacitor coupled, there is no need for dual voltage supplies for the opamp. You can use single supply and ground, yes?
Infa-Red Remote Control
Wednesday, October 27, 2010 3:33:19 AM
A lot of people have questions about possible replacements. The 2N2907 PNP can possibly be replaced by a 2N3906 or BC327. The LM308, try substituting TL081CN. If better precision is required on R6, try using a trim-pot instead. For the IR LED and Phototransistor, try, they sell a matched set at for $3.49
darpan pathak
Infa-Red Remote Control
Friday, September 03, 2010 6:51:39 AM
in receiver circuit i think the connection between 1 and 8 is not right there will be a 5 in place of 8
Infa-Red Remote Control
Monday, July 12, 2010 8:02:22 AM
what kind of NPN PHOTOTRANSISTOR IS USED HERE? is there any substitution of LM308?
Lee, Manchester, England
Infa-Red Remote Control
Sunday, April 18, 2010 6:03:04 PM
I set up the circuit for a small project and it worked very well. In order to function correctly, the reveiver needs to calibrated so as the Centre Frequency of the Tone Decoder, matches the frequency of the output of Pin 6 of the Op Amp. this is acheived by adjusting the Potentiometer to the required resistance (2.275K according to my calculations). if its difficult to set the Potentiomter exactly use a decade counter instead. The Frequencies have to be matched because the Tone Decoder purposefully has the characteristic of a high rejection ratio of intruder IR signals, ie TV Remotes. Also it is advisable to choose an IR Emitting Diode and Phototransistor that are strongly compatible with each other to acheive the best response time. The de-coupling electrolytic capacitors external to the Tone Decoder do not have to be the exact values stated, but as close as possible. Enjoy!
Infa-Red Remote Control
Wednesday, April 14, 2010 9:17:42 AM
at what frequency does the LED of transmitter circuit emit infrared rays ? can any one help please !!!!
Infa-Red Remote Control
Sunday, April 04, 2010 2:10:12 AM
what kind of NPN PHOTOTRANSISTOR IS USED HERE? what the type (number)of Infa-Red LED ? plz tell
Infa-Red Remote Control
Friday, March 05, 2010 8:42:51 AM
This is great.
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