March 3, 2009
This is what started this project: For a long time, I wanted to buy an internet radio to get access to thousands of stations from all over the world. However, it seems the market in the US is way behind that of Europe, where (especially in the UK) you can select among many models of digital, Ethernet-equipped radios. Many of them have features such are pause and record of the audio stream.
Aren't you also intrigued with these novel picture frames, but could never justify the price of one, with better models reaching hundreds of dollars and lesser models not really worth of buying? Picture frames were one of the best selling gifts in 2008, with the average price of $169 for a connected photo frame (EE Times, Feb 23rd 2009), but people are mostly confused with the device. I've seen few in people's homes being used for few days and then collecting dust.
Adding the ability to play music to any device seems to be more of a marketing bullet than the issue of technical difficulty nowadays. Even GPS units now play MP3s. Soon microwave ovens will do the same while you wait for your lunch to heat up.
I believe all those units will eventually converge as the electronics built into them become a commodity. The prices of (small and medium size) flat panels is sharply falling by day as the yields are improving and demand keeps growing by expanding into new markets and applications.
(A little diversion: please see my article in the Linux Journal on the voice-response, remote controlled MP3 player). This time I wanted to see if a unit can be cheaply built with off-the shelf components that can do all of the things I wanted it to have for this specific purpose of a kitchen radio/picture frame.
This web page explains and demonstrates building such a unit from an old spare notebook.
The unit (called a "picture frame") currently does the following:
I wrote the client program from scratch since that's the only way I could have it exactly the way I needed it to be and also have it extensible for future needs.
I was familiar with various models of older notebooks, so I found a unit on Ebay whose seller listed it as having a rattling noise inside and trying to boot, but not being able to, so it was really not functional for him. After few email exchanges with the seller, I figured it could be a crashed hard disk which was ok for me since I did not need a hard disk (I will use solid state). That laptop had some other problems and missing things which again did not concern me, and for $75 it was a perfect bargain.
I also purchased a wireless card for that notebook which later I regretted and did not use since the resume from suspend kept taking long time to reconnect causing network problems. I ended up simply plugging in a network cable. So that $12 was a waste :-(
The other large expense was a Compact Flash drive ($45, 4Gb Crucial Lexar UDMA 300x CF) and the IDE to CF interface card for it ($35). I wanted a silent, low-power solution and a fast CF card with UDMA.
The rest of expenses was miscellaneous hardware from Home Depot and Lowes, totaling about $30.
These images show gutting the notebook apart into pieces and taking only pieces that are useful to the frame unit: motherboard, sound module and speakers, LVDS screen, memories,...
Here is a Windows XP booting up on the LVDS panel:
For the mount, I used two pieces of Plexiglas and sandwiched the guts of the notebook with some hardware. After some playing with the layout, I marked the holes. Then using a drill-press, drilled the holes for the raisers and components as well 4 larger holes on each corner for the support screws. (Yeah, I forgot to list the investment of a drill-press from Harbor Freights - but man needs tools, right?!)
To guarantee the constant height, each component is held in place by small screws and plastic spacers, as shown in this close-up:
Still, I had to hand cut some spacers to custom-fit some of the components which mounted on top of each other and were not even with the rest.
Here is a motherboard mounted, with the sound module on the right, subwoofer at the top and the CPU fan on the top-left. Sticking out are the wires for the wireless network whose receiving pads normally get glued to the back of the panel.
This corner contains the sound module with the volume control. I did not want to clutter the software interface with the sound volume - I wanted to use the physical volume control, so I positioned it to stick out from the back of the frame. I was about to set the sound level to around 80% in software and let the volume dial do the volume control. Conveniently, there are also jacks for the line-in, line-out located right next to it, which I did not plan on using right now, but they may come in handy for some future application.
Since the wires for each speaker were too short, I had to extend them. I found few old CD ROM cables that used to carry audio, so I cut them and soldered them as extensions:
I needed USB connectors right off the side of the unit so that I can plug in wireless mouse and possibly other peripherals. Initially, I needed to use the external keyboard until everything is set up. In the future, I could add the support of getting images from an USB drive or something like that. Keeps options open.
These are pretty much all components mounted - it ended up a bit crowded.
Here is it again making sure that it all works while setting up. It does look busy, but this is actually the bottom of the frame; it's turned upside down and around for the final assembly.
It still has a hard disk plugged in. There was much tweaking involved, but in the nutshell, once all the drivers were installed, I configured and installed the software, and then made the image and copied it onto the Compact Flash card.
Mounting the panel was a challenge. First I tried using the double edge tape around the edges. It did not stick strong enough and suddenly the panel would just fall down when set upright. Then I noticed tiny metal brackets on the sides of the panel. They did not have any holes in them and I believe they were used to hold the panel firmly by the plastic enclosure. I drilled very small holes on the acrylic trying not to drill through, and then used tiny screws right in between the panel and the brackets, screwing into the Plexiglas. It worked! The assembly now seemed to be very strong.
Another problem I had with an on/off (push) button. I bought few sizes of them in Fry's and in Radio Shack, but none would work or mount exactly to what I had in mind. The Plexiglas was too thick and the button screw did not quite grab the thread. The largest push-button was reaching, but it was simply ugly. Finally, I opted for a smaller button and used a good measure of hot glue on the other side to hold it in place. I am not happy with this particular design since you may feel it's moving just a bit when you press it and you'd like to hold it from the back while doing so. Here is a final picture of the frame:
Notice I've got brass screws for the 4 main corners and then red rubber protector tips pushed over the excess of each screw. I found that hardware at Lowes. I really like the final look of the assembly! There are also extra holes drilled in the top-left corner. They are artistic expression. (Well, they started as one wrongly drilled hole..)
This image shows the final unit sitting on our kitchen counter.
Another close-up with the software running:
The unit is always ready to be quickly resumed from suspend and within few seconds it shows the user interface. From there you can browse the music selection, listen to the radio or see the pictures. It sits in a common, busy and a prominent place in the house so when used as a picture frame, as pictures are changing, it is very eye-catching. Sometimes we just stand there and look at our last 15 years of digital pictures (many old were scanned in) being shown at random. (The slide show toggles into the whole screen if you click on an image; otherwise a large digital clock shows up after few minutes of inactivity)
The flat surface we also use to stack mail and stuff, so it's really part of the kitchen counter now. (It would be really neat to be able to extend the LVDS cable and have the unit hidden under the counter so only the flat panel hungs on the wall...)
I decided on using XP for the OS since I could quite easily write my application in C#, and I know the power management drivers are supplied by the vendor. I used XP Lite to trim down the OS to bare minimun, stripping down components in order to comfortably fit them onto a 4Gb flash card. The other reason for heavy trimming was to get rid of all unnecessary services and drivers (and XP comes with a lot of that!).
After everything was set up and working from a hard disk, I backed up a partition and copied it onto a bootable CF card plugged into an IDE to CF adapter. However, you cannot just copy a Windows partition (using Ghost) and expect it to boot, you need to do these steps:
Using an installation XP CD, boot into the recovery console and type:
ATTRIB -r-h-s C:\BOOT.INI
DEL C:\BOOT.INI
BOOTCFG /rebuild
Enter Load Identifier: XP
Enter OS Load Options: /fastdetect
FIXBOOT
This will make a new copy of the OS bootable.
Since I have a server running 24/7 in my house, I did not care keeping any of the media on this machine, since everything was already on the server (music, pictures). As it's designed now, one piece of software runs on the server (I call it "indexer") and scans the media files creating XML index file which I share through a shared folder.
The Frame software itself reads all the XML files and the media files they point to as they are needed. For the music and radio, you can create playlists by dragging and dropping albums or clusters of items. Since there is no keyboard, I put special attention to the ease of the UI and I believe I have succeeded since my wife could use it without much training :-) The GUI UI ended up simple and very intuitive, and yet it does everything it was supposed to do.
I have a list of about 6000 radio stations from all over the world. It is hard to collect such list, and indeed I could not find it anywhere on the Internet (for free, that is). So, I wrote a set of Perl scripts that harvest some of the best internet radio portals. The scripts would issue HTTP requests and then parse the result, stashing away information such as: different URLs to the stream, optional logo picture of a station, name and description, genre. Some of the portals were easy to do: they listed stations by their ID which I would simply query from 1 to 10000 or so. I had those scripts running for weeks from the server, 24/7 and collected the results. Some portals stopped talking to me when they figured out I was harvesting their data etc. but at the end I got a very nice list.
I wrote some other scripts/software that would work on that data and create a master XML list of stations for the Frame to use.
I already mentioned a digital clock which kicks in if you are not displaying images full screen. I found a free one here and installed it as a screen saver. Then I added some C# code to control it since only the application knew when it is all right for it to kick in.
For creating images from the text, this site was extremely useful. I used it to create those big buttons.
Finally, this is the snapshot of the app, (with Marilyn Monroe in it):
And the settings menu (a little toolset button on the top-right corner):
Format the storage (Compact Flash in this case) with the FAT32 file
system, not NTFS!
The latter one does random disk accesses to various hidden and virtual files
such are C:\$tmp and similar as part of the complex file system house keeping.
There is no way to turn this off (it can be minimized) but it still
(unnecessarily) accesses the CF card.
Have a backup solution for the networking.
It turned out the wireless takes really long time to reconnect after a resume.
Or that is due to this specific system/card. I ended up waiting for the wireless
card for almost a month from an eBay purchase, at the end not using it but
simply connecting a network cable to the system (parallels to the power cable,
so it's not that bad).
Do more real-world tests with the system before committing to it.
I wanted to have a vertical-standing picture-frame looking system. It turned
out the thermal cooling on that motherboard would simply not do the job when
mounted vertically! The CPU temperature would not dissipate and the fan kept
working at the full speed (the cooling rig was even too hot to the touch!) When
placed horizontally, the cooling worked fine. I ended up making a last-minute
design change to lay the whole thing horizontally, and only mount the LVDS panel
vertically, under an angle. So now it does look like a laptop that it started
with, but at least it is not thermally compromised. That's the danger of blindly
buying a machine before being able to test it for things like that.
Use screws not glue or tape.
Originally I meant to use a double-sticky tape to tape the LVDS panel to the
acrylic giving it a clean look. That worked. Well, for two days at least. The
panel went down as the tape simply detached. Ended up using small screws jammed
between the outer edges of a panel and slim panel metal brackets that just
happen to be there. Otherwise, I was running out of ideas on how to mount the
panel to that acrylic sheet. The screws are very short so they don't poke out
from the front face of the acrylic and the mount is very tight and firm. I am
very happy how that one turned out.
Mouse or touch-screen?
Touch screen would add up a cost and it would be difficult to find one that is
as large as this panel anyways. Wireless mouse purchased at Fry's for $14 worked
as fine. Tuck it away when not in use.
Operating System considerations
I used nLite to create a set of custom XP installations and kept trying them
inside a VmWare box until I was happy with the setup. nLite would make an ISO
image which I would use to do a test install in VmWare. Some things still needed
a real (target) system: for example, testing device drivers, power management
and suspend/resume. Once everything seemed all right I copied the OS partition
onto the CF card and booted off it. It all fitted nicely within 4Gb CF with
plenty of space to spare! (Although it would not fit into 2Gb)
Run FileMon to watch what's happening
Just when you think everything is setup nicely and there are no unnecessary disk
accesses to ruin your CF card in the long run, there is something causing the
machine to stutter or occasionally (but regularly) access the drive. (The CF to
IDE adapter I bought has a little LED showing the access.) Perhaps a poorly
written system control from a notebook vendor that you really don't need (a
Fn-key handler while you don't have a keyboard or something like that). FileMon
will tell you who is still not cooperating and you can remove the driver or a
component.
Be prepared for maintenance
It's never completely done! The software will show bugs once in a while; friends
will give comments which you want to address or they will have valuable
suggestions ("It would be nice if it does this and that in that way") and you
will want to implement them. More importantly, while using it on a daily basis
there will be subtle things you wish it would do, so you go and implement them.
Let it run for a while on an HDD before moving it to CF
Run the .NET application on a HDD the very first time for .NET to compile it.
Also I've found out there are few other things that the XP wants to do in the
background on a new system, so let it do all of it on a HDD, not on the CF card
due to limited number of writes that the compact flash can perform in the long
run.
Issue of having a CPU cooling fan
Having a CPU/GPU fan is not that bad as some DIY postings state. If you set
the power management right, the fan rarely turns on. The software I am running
is not that CPU intensive. The main problem was to find that performance balance
between the Intel SpeedStep and the OEM custom power management tools.
Solid state is fantastic!!!
Having used UDMA (300x) CF card instead of a notebook drive I wished to start
swapping all hard disks in my computers! :-) If they would just go down in
price... Boot times are extremely fast and there is that zapping silence while
accessing the drive. I compared the performance and the random access time of
0.4 ms is mindboggling (compared to ~16ms for the platter drive). The
average read/write profile is flat at 41 Mb/s for all the sectors (since
the solid device does not feature spinning platters). My notebook drive peaks at
35 Mb/s for outer tracks and then slows down to half that value as less
information could be stored on the inner tracks.
The unit can still be improved, but at this point it does what it was created to do; and it does it well. If I were to do it again, I would try to make it slimmer in order to put it on the wall. I would also probably just go ahead and purchase a touch screen. These screens can be mounted in front of the panel - they come with an USB interface and from the software perspective fully mimic the mouse.
Or perhaps by that time some vendor will figure out there is a market out there for such devices and will make one for a reasonable price.
Comments or suggestions? You can email me at "gdevic @ yahoo.com"