Raspberry Pi & DIY
Jun 29, 2012 at 5:37 PM Thread Starter Post #1 of 65

wakibaki

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I guess a few people had the same reaction as I had when I first saw announcements about the credit-card-sized computer that would run linux with a full GUI.

Cool. Where can I get one? When can I have it? Yesterday?

Anyway it actually arrived the day before yesterday, but I didn't have all the ancillaries to make it work. I put in a mail order, and most of the things I needed turned up today, except for the monitor. The delivery company loaded it on the wrong van, so I may not see it 'till Monday.

I got the Pi going by plugging it into a TV with HDMI, I didn't really want to have to fiddle with the cables on the TV, and I didn't have anything but a VGA monitor, but I couldnt wait for the new monitor to arrive.

I've posted this here in DIY because I think that most people who'll mess with the raspi will have a DIY bent, it's a geek's toy.

What am I going to do with it?

Well. I'm writing this post on it, if it gets used for nothing else.

One of the things I will be trying, like a lot of other people, is using it as a music (and possibly video) server. For music playback it can be run withoiut a monitor, you can talk to it over ethernet.

I recently bought a USB oscilloscope, so it may be used as a host for that, I'm not sure, I have to check out the software on Sourceforge, I know there's a third party program that runs my hardware, I just don't know if it runs under Linux.

I'm also working on a USB signal generator using an AD DDS (PCB off ebay). I've had some problems getting the USB interface going, but the raspi could end up being the controller for that, I want to move these instrument functions off the Windows box that is my main computer. If I can't solve the problems with the USB interface (in a reasonable timescale) then I may resort to trying to control the DDS using the raspi's GPIO pins.

Anyway, anyone who gets one, or who is just interested, feel free to post here. If any of the subjects raised generate a lot of interest then they can be cloned off into threads of their own.

More later...

w
 
Jun 29, 2012 at 5:44 PM Post #2 of 65
Newark postponed my shipment yet again. So now I'm set to receive it on the 5th. Must've fallen through the cracks, since they are suppose to send me an email if my order was affected by manufacturing delays. Boooo.
 
Jun 29, 2012 at 11:48 PM Post #4 of 65
may end up using one of these as an embedded crossover
 
Jun 30, 2012 at 5:34 AM Post #5 of 65
Quote:
may end up using one of these as an embedded crossover

 
 
I wondered about that.
 
I know it has HDMI audio, I guess (hope) that's eight channels (7.1?). If it is you could pre-filter a wav file into 3 or 4 frequency bands per stereo channel. It'd be costly in storage terms though, then you'd need an HDMI audio/video splitter with 8 channels of audio out...
 
Or I guess you could try an 8-channel USB interface, or even a bunch of 2-channel USB interfaces.
 
I'm not sure how you'd achieve playback though, although it's probably not too difficult to write a player, there are quite a few 2-channel ones (for Windoze) out there already, some making extraordinary claims about having better sound than others because of extraordinary buffering strategies or WHY.
 
I don't think the processor's capable of doing the processing in real time though, so I don't see inputting digital or analogue audio and outputting after a short delay, although that's just a guess on my part. I saw claims that an 850MHz x86 was sufficient, but that may have included a floating-point maths coprocessor.
 
Limiting the requirement to 1 channel in and 2 out per pi might make it more feasable. 
 
The real issue might be the quality of the DACs in the USB or HDMI interfaces, 3 ODACs is starting to stack up the cost.
 
What kind of architecture do you envisage?
 
w
 
Jul 1, 2012 at 1:30 AM Post #7 of 65
I was having a look at these today, and I saw that people have installed XMBC on it, looks great!, I wonder if the grub dac would work with it, mgiht be a very nice little desktop setup. I also found this case for them. http://builttospecstore.storenvy.com/products/404262-raspberry-pi-enclosure-kit
 
Jul 1, 2012 at 8:12 PM Post #8 of 65
Would you believe it?
 
Mine has developed a fault on the USB ports. The mouse went intermittent on me last night, so thinking that that was the problem I went and bought a new one today. Brought it back and plugged it in and got a screenful of USB hub errors on boot-up. Tried the old mouse on a Windows box and it works fine.
 
So it's back to RS for this one. I hope they've got stock to send me a replacement.
 
I don't think it's indicative of a design fault, early life is when part failures are most common, I guess they just give them a functional test without any burn-in to keep the costs down, that's what I would do.
 
Grrrrr.
 
w
 
Jul 1, 2012 at 8:21 PM Post #9 of 65
The usb fault has been documented, and they have suggested that it is possibly related to a weak power supply. Try swapping it out with something else?
 
Jul 1, 2012 at 10:23 PM Post #10 of 65
Thanks for that. After reading what you wrote I googled for the problem (I was convinced previously there was a hardware fault) and I see that PSU issues can cause problems like this. It's a new 1A power supply, but I guess it could be at fault, I'll try and find another one or maybe build a regulated one that I'll have confidence in, I've got a few things I could steal an A socket off.
 
w
 
Jul 5, 2012 at 12:19 PM Post #12 of 65
Hi,
 
This is my first post on Head-Fi - here goes ...
 
My Raspberry Pi turned up a couple of days ago, and I also  have PSU problems. So far I've tried 3 x different PSUs and with each one, I see problems varying between constant reboots/USB freezing/network interface dropping out. From reading various forums, it seems that there's no voltage regulator on the Pi, so it's a little bit picky in terms of which USB PSUs will work.
 
There is a list of verified RPi hardware (including PSUs) here   http://elinux.org/RPi_VerifiedPeripherals
 
Based on that list, I've just ordered this 2A PSU from Amazon UK for £4.99, which I'm hoping will do the trick:    http://www.amazon.co.uk/CostMad-Technology-Certified-Approved-Universal/dp/B005NZKTRG
 
Once I get it working, I'm planning(/hoping) to run it headless, plug it into my E-Dac and run Squeezeslave to use it to stream audio from my Linux box that's running Logitech Squeezeserver.
 
Jul 5, 2012 at 2:58 PM Post #13 of 65
I'm having difficulty making up my mind whether it's working OK or not. I think the problem I was having getting it to boot was PSU related, because I had the mouse and keyboard plugged into the regular USB ports on the board, and when I put the powered USB hub into the system it would boot again, but I'm having problems with the mouse becoming unresponsive. It doesn't stop altogether, just moves so slow that it's almost useless, I keep on overshooting the buttons and I have to click multiple times. Then the Ethernet seems slow too, pages take forever to load.
 
I've (just) ordered one of those 'CostMad' 2A jobs from Amazon, should get here Saturday, maybe Monday. I might get impatient and build one.
 
I bought a second SD card to try a different distro.
 
Does anybody know of a comprehensive set of instructions on how to make a USB DAC work under a virgin install of Debian (or any other distro)?
 
w
 
Jul 5, 2012 at 3:15 PM Post #14 of 65
which chip? You'll have to load the right ALSA device driver. I remember that TI's pcm2702 usb dac works right out of the box.
 
Also, I'd simply go headless on the thing. If you really need to, xtunnel to the thing via ssh.
 
Jul 5, 2012 at 6:40 PM Post #15 of 65
Agree about going headless and connecting over ssh being the way forward. This is how I plan to use it once I have the power/network stabilised.
 
I've read that it's easy to configure how much memory is assigned to graphics duties, and how much is available as system memory. As there's only 256GB overall, even with the lightweight windowing system, I'm inclined to use as much memory as possible for the system and go headless. I'd rather avoid paging to an SD card swap partition and burning up the write cycles.
 
I'm hoping that PSU does the trick for you - I'll report back when I get a chance to try mine out. If you look in the system log you'll see the network interface going up and down, and something like "failed to read register on eth0". This seems to be symptomatic of a lack of power.
 
There's a reasonable chance that the DAC will get auto-detected and the right kernel driver subsequently gets loaded - you need to then set it as the default sound device. I know it's not identical, but on Ubuntu my DAC just worked, so fingers crossed.
 
Just for reference I found a troubleshooting page here:  http://elinux.org/R-Pi_Troubleshooting
 

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