Hello guys. I'm trying to add to a project an Infrared function, that will only identify IR presence, no need to decode anything, simple binaryism. I took an IR receiver off of an old toy, and connected it to an Uno's digital pin (and 5V / 3.3V & gnd...).
It responds very well and from long ranges to IR remotes I have in my house - when i press any key on a remote the Uno shows 0 instead of 1.
I took an IR led from an old remote and connected it with 2X AAA batteries (=3V) and a 220ohm resistor, and it only responds within very close range - less than ~5cm.
I tried various resistor values down to 22ohm, and got the same result, except that in the latter try the led got hot..
I thought the problem might be the led so I took another one from another remote that worked well with the receiver, but got the same bad results with my application.
Any suggestions? I'm wasting hours on this thing I don't know what to do.
Thanks
You can run the receiver without an MCU. I've seen it done, the receiver was just connected directly to an LED. This was part of an experiment for a 10 year old student.
The IR module you show has a built in 38kHz (or similar frequency) filter and demodulator. So it should register raw pulse trains at the output that can be used for simple triggering without any decoding. The range should be the same as with decoding.
If it doesn't work that way, you've connected it wrong. So please show us what you've done.
That's not what @Bezzero is asking about. He wants to run the transmitter without any chip!
@Bezzero your receiver is deliberately designed to ignore simple IR light sources. If it did not do this, your TV would be unable to receive commands from its own remote, except perhaps inside a completely dark freezer room! In a normally lit room at normal temperature, there would be so many other IR light sources that the remote's signal could not be received. To overcome that problem, the remote transmits and the receiver receives at the exact same modulation frequency somewhere in the range 35~45KHz. Other natural IR light sources don't modulate at that frequency and so they are ignored by the receiver.
Thanks for replying and understanding.
But isn't the ignoring algorithmic? Doesn't the receiver has the ability to recognize my IR led?
It does recognize it at certain conditions.
I think they only come with the receiver module too. So cost-wise, it might be cheaper to use an ATTiny85 or a Pro Mini. Just be careful about modules that say they are for 38k, but don't have the modulator at all. I think the KY-005 is one of those.
Or you could build your own 555 circuit to generate 38KHz. But really, a little microcontroller is going to be easier and cheaper.
Not exactly algorithmic. There is a "tuned circuit" which is part of the receiver chip. Like a radio tuned into a particular station, it is tuned to 38KHz (or whatever) and ignores IR signals at other frequencies or IR signals that are not modulated. At very close range, the receiver probably gets overwhelmed by the strong IR signal and changes its output because of that. It's not really 'recognising' anything.
What are you trying to do with the transmitter/receiver? You could substitute a simple photodiode or phototransistor circuit for the module, it would respond quite well to an IR LED or other IR source, but a transmission of on/off light is subject to the interference from other sources that was mentioned in some posts above. So, it would be extremely helpful to know, what you intend to use this for...
Hi
Since you disassembled the Remote Control to remove the LED, how about using its chip inside a small box with only one button, (simulating a qq key on the Remote Control).
RV mineirin
That actually a good idea, thank you.
I have it's motherboard so I could just use that to generate any defined command from it so I only need one it doesn't matter which it is. I hope I'm understandable.
If you have any further tips I'd love to know.
Thanks again
I made a project (with a 3d printed enclosure) that flips the light switch by a double clap or a button press. It has an Arduino nano, microphone module, button and a servo.
I want to add the option to make the flip with a remote as well.
I have some photoresistors,do you think they will work for this with an IR led?
They will, but not very well because their peak sensistivity is in the yellow-green part of the spectrum. Also their response is extremely slow, orders of magnitude worse than a silicon part.
I think your tests were not sensitive enough. How did you make the measurement? There should be a response, even if it is very weak. The spectral bandwidth of CdS is not pure.
I'm having some trouble activating it. I the original remote came with these silicone buttons that complete the circuit of the button-like motherboard parts, due to their conductive ingredients, so I have read.
I tried taping some copper / solder wire so it completes the circuit all the time, and then adding a button on whole the circuit, but the wires only triggered it when I pressed it down. How would you solve that?
Thanks
