I just currently bought a Magnavox LCD TV (15MF00T/37) and I am trying to add voice recognition to it for someone that is not physically able to press the buttons themselves. The problem is I do not know the binary codes that are sent out after each command (ex. Channel Up, Channel Down, etc). I was wondering if someone knew where I could find that information, or maybe a place that sold universal remotes that would release that information along with the remote to me?
Also, I have been trying to figure out the frequency at which the information is coming out of the remote. I thought it would be either 36kHz or 38kHz, so I bought several infrared modules at those two frequencies. I hooked an oscilloscope up to the output pin and all I received was noise. If someone could PLEASE help me, I will be soooooo grateful
There is a JP1 upgrade posted for Magnavox 15MF050v17 LCD TV. Probably your TV uses the same code set as that one, but I can't be certain.
That one is 38Khz, but there are lots of ways you might have misunderstood what you were seeing when you tried the infrared module and oscilloscope.
What device do you plan to use to transmit the IR signal? Or are you still trying to figure that out?
I have a very detailed understanding of the structure of the IR signals in the above mentioned JP1 upgrade as well as those in more typical Magnavox devices. If I knew what form you wanted the information in, I'm sure I could help.
First off, thanks for taking the time out to reply to my post! The device that I am using is a microcontroller called a basic stamp2 made by parallax. I am planning on programming that and outputting the appropriate code(requested command) to the Magnavox TV.
I probably was interpreting the signal that I was observing from the oscilloscope incorrectly. I’ll set it up and observe it again.
The form that I needed the codes in is binary I believe. I was reading about the different protocols that TV remotes use; for example, some TV’s send out pulsated signals that contain some start bit information, an address, as well as the command information (all in binary). I was a little confused about that.
38.4k The modulation is aprox 38.4Khz. The exact value doesn't matter. Anything close will work, certainly 36.9 to 39.9 are OK, probably an even wider range.
564 The durations used in the following sections are in units of 564 microseconds. Again, that is aprox. Anything close will work.
1,-1 A data '0' bit is represented by 1 unit (564 microseconds) of modulation followed by 1 unit of silence.
1,-3 A data '1' bit is represented by 1 unit (564 microseconds) of modulation followed by 3 units of silence.
16,-8 A signal starts with a "lead in" of 16 units of modulation followed by 8 units of silence.
D:8,S:8,F:8,~F:8 The content of the signal is 8 device bits, 8 subdevice bits, 8 function bits and 8 complement of function bits, each of the 32 bits represented as described earlier, and the 8 bits in each group sent least significant first.
1,-78 The 32 bits are followed by a "lead out" of 1 unit of modulation followed by 78 units of silence.
(16,-4,1,-173)* All of the above is then followed by several repititions of 16 units of modulation, 4 units of silence, 1 unit of modulation and 173 units of silence. The total duration of those repetitions duplicates the total time the user pressed the button on the remote. For some functions (such as Vol+) that duration affects the TV's behavior. For most commands the duration is ignored by the TV.
For that upgrade I mentioned, the "device" is 65, the "subdevice" is 1 and the functions are various number from 1 to 29.
If most of the above makes sense, I can fill in a few more details.
Depending on how hard it is for you to program your device, we may want to do more to confirm that we have the right code set before you spend time programming.
Most people in this group test to find the code set of obscure devices by learning the signals into a JP1 learning remote and loading them to a PC via JP1 cable and looking at the decode in the JP1 software. That way may be the easiest for you, but there are several other possible ways (in case you don't have a JP1 learning remote).
