I'm building up a project to transmit data from one computer to another computer from a wireless media and I have to use LEDs for this purpose (As per the requirements of the project, so I can't use laser diodes). I'm thinking about using the USB to RS232 module, an Op-amp, a schmitt trigger and a SHARP IR sensor to send the light signals and a photo-transistor.

I'm going to do it like this:

1. Connect a serial monitor to the PC
2. Use RS232 module Tx pin to drive a switching transistor which is connected to the SHARP
   sensor's Vcc Pin
3. In the receiving circuit, get the light coming from the IR Sensor IR LED using the 
   photo-diode and connect it to a schmitt trigger
4. Connect the schmitt trigger output to an Op-Amp
5. Connect the Op-Amp output to another RS232 module Rx pin and read data from a
   serial monitor

I'm just wondering if the above selection of items are the appropriate ones. The receiver has to be 1m away from the transmitter. So are there any other options I can use other than the SHARP IR sensor?


1 Answer 1


You have proposed to use a Sharp IR sensor as the thing to send out your signal. That will not work as that part is a sensor (or more exactly a receiver part).

You should look at using a actual light emitter for the transmit section of your project. That could be an actual visible light LED or an infrared LED like the type located in any TV remote control.

  • \$\begingroup\$ Using a TV remote LED, would it be affected by the ambient light? \$\endgroup\$
    – Padmal
    Commented Apr 24, 2016 at 13:28
  • \$\begingroup\$ Well TV remote controls work in ambient light right? They have found a solution for that problem!! The transmit signal is modulated with a 38 KHz or 40 KHz carrier signal. \$\endgroup\$ Commented Apr 24, 2016 at 13:34
  • \$\begingroup\$ Thanks Michael! I'll go for a modulation scheme using IR LEDs to my project! \$\endgroup\$
    – Padmal
    Commented Apr 24, 2016 at 13:38

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