IR remote control

Thread Starter

q12x

Joined Sep 25, 2015
499
- Give me your best IR remote circuit that you can think of/know of, and that is working optimal at least 4meter distance.
My desire is to use 2 remotes with a IR led and a single receiver on the wall.
Can you help me on that?
This circuit I found on internet the other days:
1614798065545.png
I want to believe it will behave the best and in my parameters I want it.
If you have your own design, Im happy to see it. I kind of finding this circuit, that is a bit hard because of the double power supply I must insert, and I very much want to avoid that. And also at 5V, and not at 12V as this is offering. I also only have the uA741 opamp and not the same from the circuit but it will work fine, I imagine.
But if no alternatives works, then this will serve as the backup plan.
I never built such circuit in my life. I'm a rookie at it.
That's why I need your thoughts and experience if you build one in your life.
Or some advice on this one that I find. It's up to you.
Thank you !
 
Last edited:

wayneh

Joined Sep 9, 2010
17,031
It's great that you're using a modulated signal. That's the only practical way to get the distance you want.

I would not use that receiver circuit, though. There are purpose-built IR receiver modules that can handle the demodulation for you. One common 'problem' beginners find with these is that they do not hold on or off in response to a steady, modulated signal. They will produce a pulse when they see the signal but will not stay on. There are exceptions, I think.

Example detector. There are many more.
https://www.mouser.com/ProductDetai...s/GP1UM281QKVF/?qs=bgJ5QXnU1LT8%2BbSuBmSm2w==

If you want to continue with that circuit and avoid a dual supply, just choose a rail-to-rail op-amp or at least one that includes the ground rail. I think LM358 would work. I'd avoid the 741 unless you decide to use the dual supply and use more than a split of just 5V. A split supply with ±5V might be OK.
 
Last edited:

AlbertHall

Joined Jun 4, 2014
11,102
I would not use that receiver circuit, though. There are purpose-built IR receiver modules that can handle the demodulation for you.
But that gets a lot more complicated if you want to control two motors as TS does.
With the original circuit, you could have a transmitter which can send two different frequencies and two receivers tuned to different frequencies.
 

Thread Starter

q12x

Joined Sep 25, 2015
499
If you want to continue with that circuit and avoid a dual supply, just choose a rail-to-rail op-amp or at least one that includes the ground rail. I think LM358 would work.
I received multiple hints for using LM358 instead of uA471, in time and from diverse people. I think it is time to actually buy them. I am not that great working with opamps so I hesitated. I should have trusted those people from the beginning.
I like how you describe LM358 in this situation! Can you explain this part a bit more for me please: "just choose a rail-to-rail op-amp or at least one that includes the ground rail" ? I know already that LM358 has a rail to rail functionality. But I didn't know it had the 0V rail as well, which means it has 3 rails. I didn't know it's even a criteria to search for. Again, I am new to opamps and try to believe me, what I ask is very sincere.

Example detector. There are many more.
These are the IR leds and detectors I already have in stock. They are good or bad? The transparent ones are the IR leds and the black ones are the IR receivers. They are 3mm diameter and I believe, the leds are "super bright" technology.
1614820663257.png
Thank you for your answer.
 

wayneh

Joined Sep 9, 2010
17,031
Can you explain this part a bit more for me please: "just choose a rail-to-rail op-amp or at least one that includes the ground rail" ? I know already that LM358 has a rail to rail functionality.
No, it’s called a single supply op-amp. That means it can sense (its common mode range) down to the negative rail. It cannot sense voltages within about 1.5V of the positive rail

A dual-supply opamp like the 741 cannot sense near to either rail. A rail-to-rail opamp can sense near to both power rails. They all are fed two power rails with a delta-V between those rails. You don’t really need a “dual” supply for any of them.
These are the IR leds and detectors I already have in stock. They are good or bad? The transparent ones are the IR leds and the black ones are the IR receivers. They are 3mm diameter and I believe, the leds are "super bright" technology.
They're fine but don’t have those built-in features I mentioned. They’re “naked” detectors. That may be helpful overall for your application but requires circuitry to take out the modulation frequency.
 
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