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Decoding an IR remote RC2094501/B but getting random codes
Clockwerk:
Hi everyone, this seems to be my first post here...
I am trying to decode an IR remote control that I have, however, unlike some other remotes that I own this one returns random codes every time I press a key. I am using Arduino for this project with a TSOP4838 38kHz from Vishay (here is the datasheet: https://www.vishay.com/docs/82459/tsop48.pdf). Unfortunately, I do not have an oscilloscope :-BROKE and I am still gathering knowledge on this matter.
* The remote control seems to be a "Philips" based one, it reads RC2094501/B. And it is for a mediabox for an Internet company named UPC (now Virgin Media).
* Most likely, the remote´s protocol is RC-MM, RC5 or RC6. I would say it is RC6 after some research but I do not really know.
* I have tried some libraries like IRremote, IRLib and IRLib2 but it decodes the IR signal as UNKNOWN. Furthermore, it returns random values all the time pressing the same button.
* The serial plotter on the Arduino IDE is not really helpful, but I can see the signal there at least.
* The remote control needs to be paired with the mediabox, not sure if that matters for decoding but I doubt so.
This is the sample data captured pasted on pastebin as it is a bit large: sample1 https://pastebin.com/wMa2AfAb sample2 https://pastebin.com/aBaRkABV and this is the output of IRrecvDump https://pastebin.com/KTqG0aXj.
This is some information I gathered while trying to figure out things (no success yet |O):
https://www.sbprojects.net/knowledge/ir/rcmm.php
https://www.sbprojects.net/knowledge/ir/rc6.php
http://www.righto.com/2010/12/64-bit-rc6-codes-arduino-and-xbox.html
http://wiki.electronics-irc.net/Avr_rc5_remote_control
https://www.avrfreaks.net/projects/philips-rcmm-ir-receiver
I also watched "EEVblog #506 - IR Remote Control Arduino Protocol Tutorial" which is very inspiring but a bit hard to achieve with this remote and in my case specially with the tools I have.
If someone knows how to decode this remote... or if anyone can provide some guidance that would be really appreciated (perhaps this should be on the noobs forum), also I am trying to figure how to get the output from A0 on the Arduino and plot it in something I can zoom in, etc. So I have higher chances to see what is actually going on.
This is an image of the remote and the box:
macboy:
You can view the output of the IR module with a sound card and any of many free oscilloscope software on a computer. After demodulation by the IR module, the remaining signal is just a series of pulses at a rate of a few hundred per second, easily within the audible range.
In my experience, IR modules are picky about noise. Put a small value resistor (10 to 100 ohms) in series with the power supply (Vcc), and a capacitor (1 to 100 uF) across the module's power pins (Vcc, GND). Also, the output of these is usually an open-collector type of active low digital output with only a weak pull-up. It may have trouble getting a clean output signal due to parasitic capacitance. Add a pull-up resistor to the output to help square it up: about 10k from the output to Vcc.
Seekonk:
I just built an IR repeater and shouldn't have been surprised that the receiver module puts out a lot of noise due to the AGC until it sees a real signal. I have also seen some instability I assume was power supply related. You are blind without a scope.
Clockwerk:
--- Quote from: macboy on April 10, 2019, 01:15:25 pm ---You can view the output of the IR module with a sound card and any of many free oscilloscope software on a computer. After demodulation by the IR module, the remaining signal is just a series of pulses at a rate of a few hundred per second, easily within the audible range. In my experience, IR modules are picky about noise.
--- End quote ---
I found this Java tool "ProtocolAnalyzer" today, http://wiki.nethome.nu/doku.php/analyzer/start which turns out can decode RC/RC6 (I´m assuming that is the protocol the remote actually uses). I went so happy to try it... but nopes. It seems I cannot just feed the program with the A0 output of the arduino on ttyUSB0 (Linux user here). However, it seems to like some audio device instead.
And then your comment is very relevant with nice insights really. But, how do I view the output of A0 with my computer´s soundcard? should I save the analog output as .wav from the arduino or maybe use a wire with a jack and connect it to the IR and the computer ? I´m aware this is simple and obvious for many people, sorry about that.
Also, I have tried what you mention about smoothing the signal and I used a 100uF and 10uF cap with the 10K pullup resistor. Whereas I think that helps - and it is what is suggested on the datasheet - I still get random codes regardless of the button pressed or how many times. The source of power to the IR LED is the 5V from the Arduino.
I believe the comment from Seekonk goes on the line of what you said too. I would like to be even more sure but noise or power doesn´t seem to be the culprit here, though.
Here is how it looks like in the mini breadboard atm, and some short video where you can see how a SAMSUNG remote just works, but not the RC2094501/B remote.
tooki:
Googling the model number of the remote plus “IR codes” found a few discussions about this. Consensus is that it’s “RCMM with toggle bits”, whatever that means. Apparently most IR libraries and devices don’t know how to handle toggle bits.
https://www.computerbase.de/forum/threads/fernbedienungsprotokoll-herausfinden.1092274/
http://dangerousprototypes.com/forum/viewtopic.php?f=29&t=4191
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