IR signal not accepted by AC

Projects Programming
1

Hi everybody,
I'm trying to control my AC using Arduino. I have bought an IR transmitter and receiver.

I've been able to decode my remote control, it's using Samsung protocol.
I have copied the signal, and sent this signal to my receiver as a test which verified it was decoded correctly.

Signal read from original remote control:
Protocol=Samsung48 Address=0xB24D Command=0x3FD Raw-Data=0xFC03 48 bits LSB first
Send with: IrSender.sendSamsung48(0xB24D, 0x3FD, );

When sending the copied signal to my receiver it prints:
Decoded protocol: Samsung48, decoded raw data: FC03, decoded address: B24D, decoded command: 3FD

I have then sent the same signal to my AC which doesn't respond. Does the decoding look correct?

Am I doing something wrong? The signals should be identical.

Any help would be much appreciated! I really want to make this work.

2

There was a guy, AnalysIR, super-active in this field, who would jump in on anything about IR r/c, especially a/c.
Get AnalysIR

3

I'm actually creating a post on their forum as we speak. I've also recently posted on Reddit and RemoteCentral.com, but nobody has been able to help so far.
Thanks for your input.

4

The transmit LED may not emit at the correct wavelength (850 and 940nm do not overlap), or the modulation frequency (typically, but not always 38 kHz) may be incorrect.

5

I was thinking that, it seems like it doesn't see the diode. I hope it's not the modulation frequency, cause all I can find are 38khz transmitters. I guess my next step then is to buy a few different IR diodes, which leaves me with one question:

Can I buy just the diode itself, and the Arduino handles the coding, or does it need to be on a circuitboard? I ask because I can find plenty of diodes of different wavelengths, but the circuitboard-diodes on Ebay doesn't say which wavelengths they are.

6

Distributors like Mouser, Digikey, etc. sell single LEDs with well defined characteristics. You could also scavenge IR LEDs from discarded remotes. They can be found at thrift stores or computer recycling shops for next to nothing.

That would take care of the wavelength problem, but if the modulation frequency is not correct, you really need to know what it is. 50 kHz is not uncommon!

An oscilloscope connected to an IR LED (used as a photodiode) should immediately reveal the modulation frequency used by the working remote.

8

Thanks for your help.
Just to be clear, carrier frequency can't be changed in software, right? I've found a code where you can set the carrier frequency manually?
edit: It seems I can. In old codes I've found it's easy to set the frequency, but in newer codes it's not mentioned at all. Only carrier PWM, which I assume is not the same? I don't know how to change the frequency, can't find anything about it.

9

If the carrier frequency is generated in software, as it is in the IRRemote library, then yes. It is usually done with one of the timers.

You forgot to tell us anything about the software you are using.

10

IRremote, I've tried all the different send and receive versions. I'm still testing, trying to find that carrierfrequency.

I found one command, somethingsomething_Micros set to 20us, which would be 50khz. Trying to find that code again, can't remember where I saw it.

11

Lots of great documentation in the IRRemote pages. Worth a read!

12

I remember from reading AnalysIR's posts that a/c strings are much longer (for whatever reason) than TV remotes.
I think Shirriff's IRremote is. . . inadequate.
But I'm not an expert

You can use Search, here, to hunt through AnalysIR's posts.

13

Do you think it matters whether I use 36, 38 or 40khz etc? It makes testing a whole lot easier if I can only stick to 38 and 50khz. Google has surprisingly little information about carrier frequencies, I was hoping for a typical frequency for AC's.

14

Yes, the frequency matters a lot. See this overview for a typical commercial receiver IC example.

Capture

15

Thanks again.
I have gone through all frequencies with a ton of different settings, constantly using my receiver to verify what I'm sending. Someone told me the different wavelengths of the diodes don't overlap, so I'll order a new one.

You've been very helpful.

16

Hello, how are you, did you manage to find the correct configuration so that the air accepts the commands, with a diode of a specific frequency you managed to have results. ?

17

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