Using multiple IR receivers with Arduino, to increase receiver coverage

Following on from my previous post describing my test circuits for an IR tagger system, here’s a schematic of the multiple IR receiver circuit:

IR receiver schematic

Receiver Pic 2Using the following components:

4 x IR receivers – TSOP4838

1 x dual 4 input AND gate – cd74hc21e

You’ll notice that The schematic has a 4 input AND gate doing nothing. This is because it was easier for me to get a dual 4 input AND gate than it was to get individual 4 input and gates.

Since these IR receivers have an effective receiving angle of about 90 degrees, 4 units should give a full 360 degree coverage. The active low outputs from the receivers are combined, so that if any of the receivers get all or part of a signal, it will be seen at the output (note: if the receivers get different signals at the same time, it will scramble them together).

 

I’m putting together a small prototype PCB so that I can just hook this circuit up to the Arduino board as if it were a single IR receiver.

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17 thoughts on “Using multiple IR receivers with Arduino, to increase receiver coverage

  1. Pingback: Databullets #2 – A.R.M.S Pistol Mk. 1 – or: Something for Poland | Tesla and I

  2. Use a 4 INPUT NAND gate instead of a AND gate could be better because the TSOP state when not receiving is HIGH and LOW when receiving. Don’t you?

    • It depends entirely on what the software is looking for. I’m using an arduino library that is set up for an active low input. If I used a NAND gate, I’d have to set up the software to accept an active high input. If thats what your software is looking for, then absolutely, use a NAND gate. But if your software is looking for the input from a single TSOP, you need an AND gate

    • Yeah, I’ve been meaning to update this post. You’re right, because each sensor has a pulldown transistor in it, and a 33kOhm pullup, so the transistor should be able to handle the small current it’d need to draw to pull down a stack of sensors. But when wrote that post I hadn’t bothered checking the circuit diagram… oops.

      • Hi. So you mean that nand or and chip is useless?
        I saw on datasheet that it could require a small transistor and resistor.

    • Hi there. As mentioned in the post, these IR receivers have “active low” outputs, so the output is notmally HIGH and goes LOW to represent a received bit. So you want the output of the circuit to go to 0V whenever any of the receivers’ output goes low. If you used an OR gate, it would always have a 5V output.

      Note: I really need to update these posts. As rightly pointed out by a previous commenter, the transistor inside the receiver is capable of pulling down the voltage of several receivers. If you look at the circuit diagram on the datasheets, showing what’s going on inside the receiver, you see that there’s a large receiver between the output and the 5V power supply, pulling it up to its Normally HIGH output, and there’s a transistor that grounds the output when outputting a bit. The practical upshot of this is that if you connect the outputs DIRECTLY TOGETHER (with no AND gate), the transistor from any one of the receivers will be able to pull the combined output LOW, achieving the same thing. Not sure how many you can link together, but essentially: connect all of the output pins together, forget the AND gate.

      • Hey, thanks for the quick comeback 🙂 I was researching for a similar project like yours and stumbled upon this, and it helped. Probably I didn’t pay attention to the fact that their output was active low, so I messed up. Partially I understood your response, but there’s still something I didn’t get: according to the AND gate logic, you’l get a “1” when you aren’t receiving anything (as the outputs are active low), while when they are receiving, they will pull your output low for each transition of the (modulated) signal. Is it correct? Then, if you are using the active high logic, you would have to use a transistor to invert the signal? Thanks, and sorry for the trouble 🙂

      • You’re interpretation seems correct. But like I said, you don’t really need the AND gate, and can connect the outputs together. If you need to get an active high from the active low, you could us a transistor to invert the signal. If, on the other hand, you’re combining multiple active high outputs, you might be able to just combine the outputs (depending on the sensor’s internal circuitry), or us an OR gate. Give me details of what devices you’ve got and what you’re doing with them, and I’ll be able to be more specific.

      • Hi, thanks, I am still in the process of choosing the components, I’ll get back to you after I have my prototype.

  3. If i want to use just 2 IR Receiver and want to keep them away apart from wall, then in this case can i use 2 ir in parallel or i have to add some other component

    • That comment was a bit hard to understand, but if you’re asking about having two IR receivers separated by a wall: Correct, the physical location of the receivers shouldn’t matter, within reason. I’d be surprised if you had any issues putting the receivers in different rooms of a building. You should be able to just wire up your receivers in parallel with a common ground, common +5V, and common signal wire. Simple as that. No other components required.

      If you’re separating the receivers by any significant distance (>5m), I’d appreciate some feedback on how it performs, just to confirm that I’m right about the negligible effect of long signal wires.

      • Hi, sorry for short description, actually I don’t know more about electronics i am a software developer, Actually i want to place my Android Tv Device at back of my LED Tv, butt when i place it at back then i am unable to control device with remote so thats why i want to add another IR Receiver with some long with so that the IR Receiver can be place somewhere in front and i can control my device.

        For this i want to know if i can use 2 IR Receiver in parallel or i have to use in some other way.
        I need your help please.

  4. By attaching with a wire, solding the one end on wire with extra IR Receiver and the other end of wire on the board with existing IR Receiver.

    • You haven’t given enough information for me to even guess if that’s a good idea or not. Just bear in mind that not all IR receivers are the same. Some use different IR wavelengths/carrier frequencies, or might have different internal wiring.

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