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IR Receiver TSOP34138

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ZOR100

New Member
I have looked at other threads but nothing jumps out. All I am trying to do is use an Infrared receiver device TSOP34138 with a standard TV remote controller. All I want to do is press any key and get a proper 0 or 1 out of the device. I have taken the output of the device into the base of a transistor and looked at the output of the collector on a meter. The output is a few volts less than my input voltage, and increases marginally when I press any key on my remote.

I ideallt am trying to end up with a toggle switch, ie press a remote button it goes high, press again it goes low.

Does anyone have a link to a circuit that works. I have followed so many and breadboarded to find they don't work. Thanks
 

ZOR100

New Member
Thankyou, I realise now a meter is just going to measure RMS voltage. Using a micro-controller would be like learning a new language, although probably worthwhile if I was going to do this a lot. Seems crazy there seems no easy way to do just a simple IR remote system, I'm not looking for anything other thn a toggle switch function. I made an astable circuit with a 555. It triggered it on, and if I moved my IR chip output to the reset pin it reset it. All I wanted to do was find a way to toggle my IR chip output over each time to trigger/reset. However I might have then found a need to delay that to stop bounce holding the remote control button too long. Never mind, will eep looking. But thanks for coming in, liked your website
 

jpanhalt

Well-Known Member
Most Helpful Member
You haven't been consistent in describing what you really want to do. At first, it seemed you wanted to decode a TV remote controller, and you got an answer for that.

If all you want is an IR switch, then maybe this circuit will help for the transmitter:
View attachment 64250

And this ( View attachment 64251) is the file you can use with LTSpice to simulate it.

I suggest you read the datasheet for the IR receiver you have, particularly the sections on the type of signal it requires and what it does when it receives a steady signal. That is, its sensitivity is reduced to almost nothing.

John
 
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ZOR100

New Member
Many thanks. Im sorry if I was not so clear. I initiated th project by adopting a TV remote control as a shortcut for a transmitter, not realising the implications of it being modulated the way it was. Learnt my lesson on that. Am I correct (still learning) the transmitter circuit you have been good enough to attach is a straight 38khz or whatever generator? So providing a constant frewuency.

I thought the IR receiver device would give a logic output, again learnt a lesson.

I will build your transmitter circuit and give it a try.

The file to use with the LTSpice is all new to me, I will do some reading up.

Just a couple of questions regarding the ciruit, V1 Rserv? is this the supply, and the words tran 0 10 0.1 , is this a drawing number, I'm taking it as being ground.

Many thanks again
 

jpanhalt

Well-Known Member
Most Helpful Member
The transmitter circuit provides packets of 38 KHz exactly as the receiver needs. You can use it on/off to control the receiver.

Here is a png of its output:View attachment 64253

As for the asc file, I included that as a bit of a nudge. I assume you are on the young side of 60, so using such simulators is probably not entirely foreign to you. LT Spice is a free program from Linear. It is quite popular and intuitive to use. You should be able to install the program, then load the asc file and see the signal that the circuit produces. You can zoom in and play with it to your heart's content.

If you do anything more in electronics, and I hope you do, learning to use simulators will help immeasurably.

Edit: V1 is the supply voltage. The numbers you see are the code. It is just a DC supply. With different voltages, you may need to adjust some of the resistors a little, but probably not. The TSOP is quite forgiving. What voltage do you want to use?

Regards, John
 
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hexreader

Active Member
I would not recommend that you try it, but I would imagine that it ought to be possible in theory to toggle on/off in response to a standard TV remote.

It would need some receive circuitry to detect a sustained varying signal output from the TSOP, then if a varying signal is received for long enough, clock a flip-flop to perform the toggling.

I have never seen it done, but I imagine that it could be done with just a few components such as comparator and D-Type flip-flop, or maybe a few transistors, capacitors, resistors etc.

Don't ask me how it would be done though. My circuit design skills are close to zero. But I reckon it would be possible.

The down side is that the circuit would toggle for ANY button on any remote control device working at about 35kHz to 41kHz. Designing to avoid false triggering would need some thought.

jpanhalt's ideas sound more practical.
 

ZOR100

New Member
Many thanks both of you. Just wondering why you recommend me not trying jpanhalt's circuit. Maybe an error ?
Yes I also thought there must be an easy way to achieve what I want, I did not realise the complications ahead. The nearest I had got to an alternative method was using a standard IR transmitter LED into a comparator and then into a D Type Flip-Flop, but it kept changing it's state back for reasons I could not find out. I have not had a chance yet to build jpanhalt's transmitter, just hope my receiver can catch one packet of the signal and not revert back on subsequent packets. This is all totally a new area for me. I was certainly impressed with LT Spice, what a fantastic tool for designers. Hope to get back soon with update news Thanks again
 

hexreader

Active Member
Sorry, bad punctuation. I meant to recommend that you DO try jpanhalt's ideas.

Now that I read my own post, it does say the opposite of what I meant it to say :)

So, yes, an error. jpanhalt has it right.
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
I think this is exactly what the doctor ordered. https://www.tauntek.com/tinyir-learning-ir-remote-control-receiver.htm I purchased one. I just never got around to incorporating it into the intended project.

The IR receiver essentially removes the carrier frequency of whatever. A standard carrier is 38 Khz, but they can go to about 100 kHz as the usual limit.

The bits in the data stream are PCM or Pulse code modulated. The length of the pulse determines if it is a one or a zero. There are lots of protocals, including propreitary ones.

In the simplest of forms it would consist of a start bot and say 5 data bots and a stop bit.

But protocals are not that simple. There may be an extended start bit for the AGC (Automatic Gain Control) of the receiver to lock onto. Then there may be something like an instance bit, then a device number and then a code. The sequence could be repeated in complement form for example for error checking.
An example of instance is when you have multiple DVD players from the same manufacturer in your system. A device may be a DVD player and then a function.

Some functions only toggle like on/off and some raise and lower volume, so their behavior is different when you hold down the key or press it once.
 
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ZOR100

New Member
Thankyou very much, that looks neater than my receiver, and inexpensive, I will buy one.

A further question before I go too far. I am thinking of making a beam break alarm. Is it feasable to have 1 box containing the transmitter and receiver boards, having the receiving LED, but having a remote cable to slaved transmitting LED, or is 38kz too tricky. Thanks
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
This application note, should give you an idea of how the signals are generated. Basically their are bursts of the carrier frequency. It's possible that just generating the carrier should work. A wire to the transmitting LED should not be a problem. It could be if you were transmitting IR codes.

The IR LED will have a radiation pattern, so it could flood that amount of area, say 20 degrees.

I have seen beam break alarms that used a reflector at one end, so both the receiver and transmitter would be on the same side of a doorway.

Way back when, I was in a house that apparently used an IR source at one end of the hallway and a photo-multiplier at the other for an alarm system. This could have been the late 60's. Actually, the hall way had a right angle turn in it. The distance could have been 40 feet.
 
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