Iriver HXX0: remote control

[bonusbartus]

Hi,
Im using rockbox for a time and I like it
I was reading through the hardware specs for the two irivers i own, the h120 and h340 and I found out how the remote control works, now I am trying to build a IR-receiver so I can use my player at home without always having to walk to it to change a song ( lazy me)
But there are 2 things left I need to know:

1. How does the player check if a remote controll is available, I saw the gpio 30 pin was used for that, but how does it actualy do that, a switch in one of the connectors?
2. How does the original/rockbox firmware check which remote is connected? can I manualy set it somewhere?

Thanks in advance,

Bonusbartus

PS when it's working I'll post the specs for it

[bluebrother]

I have looked into the code a bit and think it works like that:

The remote type is detected through an ADC value. Just have a look into "View IO Ports" in the Debug menu (try connecting / disconnecting the remote and look at the ADC_REMOTE value). If that ADC value is read from GPIO30 (which I guess but haven't checked) this looks to me like you need to put a voltage divider to create the correct value. This also sets the remote type AFAIK. No idea how the OF handles this.

When you manage to build an IR receiver I'd also be interested in the result -- I thought about building up something myself some time ago but I wasn't able to find the time looking into it. Maybe you want to show up on irc to discuss this. Good luck!

[brenzi]

Hi

I'd be very interested in this project. I was browsing around to find a working solution or at least work in progress.
Are you still working on this? I'd be happy to contribute.
I'm new to iriver and rockbox, but I'm somewhat experienced with electronics and programming....

cheers
Alain

[brenzi]

Just had a few more thoughts about it.

As far as I understand, the remote's resistor-network goes to channel 1 of TLV08341. The datasheet says this is a 8bit 41kSPS ADC

IR remotes work with different kinds of pulse-modulation on a ~40kHz signal. So the pulse-frequency will be well below 40kHz (needs more research)

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.

As I said, I'm new to rockbox so I don't know about its abilities. Is there an expert to comment on this idea?

[Llorean]

Just as a reminder, please type out whole words for things like "something" so that translation software can actually work well.

[bluebrother]

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.

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!

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.

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]

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.

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]

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.

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.

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.

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]

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.

What controller are you using? I'd be interested in seeing what you have so far.

cheers
Alain

[brenzi]

Even if the project is old, this here might be interesting:

http://web.tiscali.it/minidisc/

That guy is working with a PIC16F84 and a digital potentiometer. If there's a small controller with integrated DAC somewhere, one could do it with less components. (which brings me back to the question: what controller are you using, bluebrother? ;-)
I guess it doesn't matter if we use a digital potentiometer or a DAC.

Actually, for the low accuracy needed it could even be enough to let the controller output a PWM signal to a RC-lowpass to get an analog signal.

[bluebrother]

Sorry I didn't answer earlier, but I'm quite busy these days -- left at 6 in the morning today for an exibition and just came back (almost midnight here ).

Actually, for the low accuracy needed it could even be enough to let the controller output a PWM signal to a RC-lowpass to get an analog signal.

I used an ATtiny2313 (mostly because I had one around from another project and because I have a hardware debugger for it -- and I don't like PICs) and simple PWM generation. I used its 16 bits timer so the resolution should be way enough.

As I'm like sleeping with eyes open atm I will post more details at some point later. Maybe I get around looking into it again over the weekend. Please don't hold your breath too much, I definitely will publish my results once its finished but uni is quite greedy regarding my time at the moment.

[harpster]

Any update on success making an unwired remote control for the H1xx? The new Olympus LS-10 (not yet released) is touting that it has a remote control that allows you to start recording from a distance. Maybe one of you could sell your design for the H1xx and make a few bucks. It would be great for those in a band who want to start the recording from stage (like me!).

[bluebrother]

Well, it's still a project of mine to complete it. Unfortunately interfacing turned out to be harder than I thought first. My try with PWM and a low pass produced jumping values due to the time the ADC requires. I tried using an R2R network but the output current wasn't enough for the ADC. That's the point where I stopped working as I changed location for a new job.

Perhaps I'll start looking into it again at some point (I haven't given up!) but the current status isn't working -- and my test hardware is somewhere out of my direct reach.

[Tirithen]

Hello, I'm trying to make a remote for my H320 as well. I would like to use the resistance values on:
http://www.rockbox.org/twiki/bin/view/Main/IriverHardwareComponents#Remote_Control

Then experiment with a pic16f84 or similar to control it via ir or just cable and buttons since I have not got a remote at all.

The thing I wonder is how to make the simplest experiment by connecting a resistor with a value of 470 ohm to RMC connector to invoke the + button . Should I simply connect the resistor from the RMC to GND or do I need to connect it in some other way? do I need to use some other resistor to tell my H320 that it has a remote connected?

Or am I doing this in a totally wrong way?