Support and General Use > Hardware
Iriver HXX0: remote control
bluebrother:
--- Quote from: brenzi on February 07, 2007, 06:21:08 PM ---Now that we have a 41kSPS ADC we could just connect a TSOP17XX IR demodulator directly to this input and do the pulse-processing in rockbox firmware. No more external electronics needed (maybe a little sth to convert the signal to a resistance.
--- End quote ---
The TSOP outputs the demodulated signal, so no more 40kHz. But decoding the remote codes in Rockbox would require some additional reading and that would need to be done with the correct timing. While it may be possible I don't think this way is feasible.
But for the record: I managed to create an external remote receiver for my h120 some weeks ago. It uses a small microcontroller, a TSPO1736 and some capacitors only. As that doesn't draw much current it should be possible running it from the 3.3V provided by the remote. The only problem I have is the time to complete the receiver -- the circuit is basically working but it's just quickly hacked together. I'm planning to release this as soon as it's finished. As I'm quite busy with uni atm don't hold your breath.
brenzi:
I guess in rockbox there are already a few "real-time" processes running. So basically I would expect it to be possible.
One more problem I see is, if the 41ksps ADC is really clocked at 41k. I can't imagine this to be necessary for a human interface. Of course IRiver needed debouncing for their remote buttons, but 41ksps seems a lot to me.
But here's another, more generic idea: Using the line in! Here the real-time problem is solved for sure. This solution would be iriver-independent, meaning it could be easily ported to any player with a line in.
The only drawback (which actually is a big drawback to me): You can't remote-control recording!
--- Quote from: bluebrother on February 08, 2007, 07:55:30 AM ---But for the record: I managed to create an external remote receiver for my h120 some weeks ago. It uses a small microcontroller, a TSPO1736 and some capacitors only. As that doesn't draw much current it should be possible running it from the 3.3V provided by the remote. The only problem I have is the time to complete the receiver -- the circuit is basically working but it's just quickly hacked together. I'm planning to release this as soon as it's finished. As I'm quite busy with uni atm don't hold your breath.
--- End quote ---
This sounds interesting and for sure is feasible. I see the following pros and cons of this approach:
pro: compatible with original firmware
pro: probably no modification for rockbox needed
con: you're restricted to the number of buttons that you find on the remote. Maybe you can manage to have some more as the 8bit ADC might be able to distinguish more resistance values than are currently used.
roolku:
--- Quote from: bluebrother on February 08, 2007, 07:55:30 AM ---The TSOP outputs the demodulated signal, so no more 40kHz. But decoding the remote codes in Rockbox would require some additional reading and that would need to be done with the correct timing. While it may be possible I don't think this way is feasible.
--- End quote ---
I looked into it this some time ago (even got myself a TSOP 1838) and I agree polling is not an option (especially with random boosting). However I thought it might be possible if an interrupt enabled GPIO could be found and a free-running timer be used to measure the time difference. It might even be possible to re-use software from the LIRC project (the early versions are still quite compact). If I get more spare time I might have another go.
bluebrother:
--- Quote from: brenzi on February 10, 2007, 05:02:23 AM ---con: you're restricted to the number of buttons that you find on the remote. Maybe you can manage to have some more as the 8bit ADC might be able to distinguish more resistance values than are currently used.
--- End quote ---
You can definitely distinguish more levels than the number of existing buttons, and you can generate the values with a much better precision as you don't have the tolerances of the resistor network the original remote uses. Of course someone needs to find out how precise this setup will be, and it needs to get additional code in Rockbox for handling the added buttons.
--- Quote from: roolku on February 10, 2007, 07:05:51 AM ---However I thought it might be possible if an interrupt enabled GPIO could be found and a free-running timer be used to measure the time difference. It might even be possible to re-use software from the LIRC project (the early versions are still quite compact). If I get more spare time I might have another go.
--- End quote ---
AFAIK there is one main problem: there is no free timer left. amiconn implemented some timer sharing for the greyscale library and backlight fading working at the same time (which means the greyscale library disables backlight fading). So while it still might be possible to do this it will get hard (and most likely conflict with other functions)
Anyway, it would be pretty interesting if someone manages to do it. I will keep working on my solution ;)
brenzi:
--- Quote from: bluebrother on February 08, 2007, 07:55:30 AM ---But for the record: I managed to create an external remote receiver for my h120 some weeks ago. It uses a small microcontroller, a TSPO1736 and some capacitors only. As that doesn't draw much current it should be possible running it from the 3.3V provided by the remote. The only problem I have is the time to complete the receiver -- the circuit is basically working but it's just quickly hacked together. I'm planning to release this as soon as it's finished. As I'm quite busy with uni atm don't hold your breath.
--- End quote ---
What controller are you using? I'd be interested in seeing what you have so far.
cheers
Alain
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