Monday, October 24, 2011

Wireless Infra Red (IR) TSOP Design Tutorial 1

May the peace and mercy of Allah be with you.


More than a years I haven’t post any article in this beloved knowledge-base blog! I miss vortex electrica so much.OK! This time we talk about an idea on how to make a IR communication from scratch!

Component: TSOP4840,TSAL6200(IR LED 940nm wavelength)

I choose TSOP4840(use in my own project) as IR receiver. It was design to be used inside remote control(TV,DVD player..etc). When we know how to design it, we can implement it anywhere such as in robotic project. Below is the internal circuit of it.

From the block diagram above, we can see the internal circuitry of the TSOP48XX. Band Pass filter is the most important part where it can filter out the noise from ambient IR wave.*TSOP4840 (40 = 40kHz bandpass filter,38 = 38kHz,52,36) .

What the bandpass filter do???? it reject any light which have frequency other than 40khz. In non-technical way represented as cartoon below. (^^)

You can read the pins assignment from TSOP4840 datasheet,the circuit for the receiver shown as below/datasheet:application_circuit.

TSALXXXX is a IR LED. Ignore the transmitter part 1st. In my design, +Vs I used is +5V. The OUT pins can be left unconnected 1st to test it functionality. When the voltage +Vs and GND supplied, the OUT value should be high almost ~5V. TSOP48XX working in active low mode, if it detect any IR light pulse ~40kHz,the the OUT pin will be ~0V!

This Infrared receiver(TSOP) only sensitive to an IR light pulse 40khz with 50% duty cycle. From the data sheet, the minimum 10 pulse should be send by the transmitter to make the TSOP able to detect it.Link

That the introduction, in the next tutorial, I'll show you the working example + video!

See ya!

Wireless InfraRed(IR) Design Tutorial 1

Wireless InfraRed(IR) Design Tutorial 2


  1. i like your post...i want to know how tv remote and TSOP in tv works can u post here?

  2. Hey
    I am have sligly simple connections for IR detector(CHQ 1838D)
    It's bandpass frequency is 38kHz

    connect a resister from pin1 to cathode of LED & connect the LED's anode to 3rd pin of IR detector.
    This will help you figure out if the IR detector works well(Simply press any key of ur remote control & the led connected to pin-1 will blink)


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