IR receiver sans op-amp

I’ve decided to investigate IR codes and sensing thereof with the Arduino. I have the UNO starter kit and this emitter/receiver assembly out of a paper shredder.

The consensus on the web is to use the IR sensor to drive an LM358 opamp to get a useable signal. However, the kit has a few BC547Bs (small signal NPN) but no opamps – and I’m not really up for making up a parts order to get one IC. Is there some circuit I could put together using one or more BC547Bs to get a good logic level signal? I was thinking something like this:

opto IR.PNG

Or, maybe two BC547s in a Darlington configuration? Is it even possible with just a couple of transistors?

I also have a 74HC00 if that would help.

opto IR.PNG

IR signals are double modulated (38kHz and data).
A 3-pin IR receiver takes care of (removes) the 38kHz part,
so only the remote data is left for the Arduino to decode.
A simple IR photo diode would pass the double modulated signal to the Arduino.
Doubt that IR libraries can decode that.
Leo…

Wawa: A simple IR photo diode would pass the double modulated signal to the Arduino. Doubt that IR libraries can decode that.

Oh. Rats! Thanks for the info, I just *assumed * the Arduino was doing everything.

Any thoughts on whether the receiver out of a junk TV or some such would provide a signal with the 38KHz stripped?

Yes, all 3-pin receivers I know demodulate to data only, but 38kHz is not the only carrier frequency used. A 36kHz receiver will work on an 38kHz signal, but with reduced sensitivity (distance). Leo..

The consensus on the web is to use the IR sensor to drive an LM358 opamp to get a useable signal

The LM358 is completely hopeless for IR code signalling, it doesn't have anything like the bandwidth required. For a simple break-beam sensor it would work, but don't assume it would therefore generalize to 40kHz signals - just a warning for people reading this and making a mental note about LM358's and IR

Here's a good example of how to amplify a signal :http://www.zolalab.com.br/eletronica_projetos/ultrasonic_talk.php

This is for an ultrasound communication application but the principle on the receiver side is the same: amplify, compare and send to the arduino. Hope that helps !

Thanks for the replies. If I don’t see a roadside TV shortly I’ll order one from Banggood. They have the bare sensor dirt cheap, like <$2/10 ea.

Per this photo of a receiver board, all I need is some passives and I’m good to go.