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| Making a digital picture frame |
| Written by David Savery |
| Sunday, 05 October 2008 16:30 |
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One of the reasons I haven't uploaded many articles lately is because I've been tasked by she-who-must-be-obeyed with some house redecoration and rearrangement projects which has left me wielding paintbrushes instead of screwdrivers and shuffling furniture instead of doing fun things with computers. One of the items on the toilet roll she had listed all my jobs onto was to lay more lagging in the loft and clear out some of the junk that's lurking in there which is where I came across a PIII laptop gathering dust. A duff keyboard, dead battery and tatty casing meant this thing had no reuse or resale value but I knew there was more life left in the old girl..... if only I could think of something useful to do with it..... Now I knew the wife wanted one of those digital picture frames for displaying the family snaps and I'd been toying with the idea of making one for a while so this seemed the perfect candidate for the job. The great thing about using an old laptop for something like this is you get a bigger, higher resolution screen than a proper off-the-shelf digital picture frame (DPF) and because this laptop is WiFi enabled I can copy pictures onto it over my wireless network rather than plugging in memory cards. This is handy for us as we have two digital cameras with different memory cards and store all our pictures on several computers (although mainly on our one Windows PC). By configuring a shared folder on the DPF computer I can map to it over the wireless network from any other computer and copy images over. Of course, if I wanted a card reader then there's nothing stopping me installing one into the frame as this laptop has both USB and a built in SD reader. For this particular project however, I'm not going to bother. Hardware installation. I'm not going to get too specific on the hardware used in this project because the computer itself is largely irrelevant as any old laptop capable of displaying photos can be used for this task. My chosen laptop happened to be ideal for the project as it was a lightweight slimline machine sporting an LCD screen and surround the same size as a piece of A4 paper meaning it would fit without adjustment into any A4 picture frame. The oak A4 certificate frame I chose was the only part I had to buy for this project costing £6.50 from Wilkinsons. At approx 3.8cm depth, this frame gives me enough space to mount the screen (encased in its surround) along with the motherboard behind it.  The first thing to do was to paint the tatty metal screen surround using copper Hammerite to neaten it up and give it a colour that blended in better with the surrounding frame. Next I disassembled the laptop and discarded the bits I didn't need – namely keyboard, trackpad, modem port, battery and PCMCIA interface. Note that it's worth checking your chosen laptop will function without these parts before binning anything! 
 In this picture some loose items, namely the CMOS battery (1), internal speaker (2) and Ethernet port (3) are shown hot-glued onto the laptop lid. The hard drive (4) was hot glued onto the motherboard with some cardboard in between to provide electrical insulation. The LCD cables (5) have been connected to the LCD panel which has been fitted back into place on the other side of this monstrosity (you can see part of the rear of the LCD panel in the lower right section). I had wanted to use a CF card as a solid state drive rather than using a hard drive, however this laptop uses a 1.8” drive and I only had a CF to 2.5” HDD interface converter so I had to stick with the laptop hard drive. While it does whirr, it's not loud enough to be noticeable or problematic.  In the above picture the whole assembly has been rotated 180 degrees and slotted into the frame. The power switch on this particular laptop consisted of little more than a sprung metal plate mounted onto a plastic ribbon. Depressing the plate shorted out contacts on the ribbon and powered up the laptop. Unfortunately this switch was deep inside my DPF (1) and the ribbon was too short to bring it nearer the edge or orientate it into a position where it could be actuated from outside of the frame. As I couldn't solder directly on to the plastic ribbon, I had to trace the contacts from the switch along the ribbon and onto the motherboard where I was able to solder a couple of very fine wires into place onto some tiny surface mount points. A hole was drilled into the top edge of the frame and a push-to-make switch scavenged from my junk box was fitted (2). This switch was connected to the wires placing it in parallel with the laptop power button to allow the DPF to be switched on or off externally. The mounting hooks can also be seen attached to the frame in this picture allowing it to eventually be hung from the wall by two nails. After this picture was taken, the two WiFi antennas were connected to the WiFi card and run around the inside of the frame (some laptops have the antenna run around the laptop screen but not this one).  It's PM on Saturday. Very very PM. Still, assembly is complete and it's on the wall. I've chipped out the plaster to run the power cable and then stuffed the channel full of filler.  A couple of hours into Sunday sees the plastering finished and repainted making a very neat and effective installation. Even the wife who normally buries her head in her hands when I get a hair-brained idea for a project thinks this is one of the better ones!  Software installation. The machine I used was a PIII 866MHz laptop with 256MB RAM and a 20GB hard drive. Not the fastest spec but I knew it would run Ubuntu so the first job was to install it using PXE as there was no CD drive. Before ripping anything apart I wanted to make sure the computer was up to the job of displaying a photo slideshow so I made sure everything was configured before work on the hardware commenced. During the PXE installation I selected OpenSSH server, Samba Server and Ubuntu Desktop as components to install. SSH would allow me to make configuration changes remotely after installation, Samba would handle the file sharing and I planned to display the pictures using the built in GL-Slideshow screen saver module from the GUI. Ubuntu installed with all hardware recognised and Gnome as the window manager. Performance seemed fine but I was disappointed with the Gnome-Screensaver app as it isn't particularly configurable. Using Synaptic, I removed Gnome-Screensaver and instead installed xscreensaver and xscreensaver-data-extra. Xscreensaver has many more options than Gnome-Screensaver providing more functionality for the GL-Slideshow module. I also installed Fluxbox using Synaptic. I hadn't played with Fluxbox much before but it's a nice lightweight window manager that loads up quicker than Gnome and uses less of the computer's resources. To try out Fluxbox, install it via Synaptic then log out. From the login screen select Options/Select Session, choose Fluxbox and click Change Session. When you log back in you'll be greeted by the minimalist Fluxbox desktop instead of Gnome. One point to make is that Fluxbox is broken under Gutsy as the menus don't work. To fix it I had to type sudo update-menus from a command prompt then log back in to Fluxbox. With Fluxbox working there were a few extras I had to configure. As there would be no keyboard or mouse on the end product I had to ensure the power button would be enough to switch the thing on and off without any other intervention. Under Apps/System/GDM Setup/Security I enabled autologin for the default user so that a password wouldn't be required to log in. I also adjusted the power management settings so the computer would shut down when the power button was pressed and the display wouldn't be put to sleep when idle. To start the xscreensaver daemon at startup, I edited ~/.fluxbox startup adding the following line under “Applications you want to run with Fluxbox”: xscreensaver & The ampersand makes xscreensaver run as a background process. I also added the following lines to enable the Network Manager applet to run without authentication: gnome-keyring-daemon & nm-applet & Upon restarting Fluxbox, the Network Manager applet appeared allowing me to assign an IP address and bind it to my wireless network. I configured Xscreensaver to use GL-Slideshow only and pointed it at the default path for my profiles pictures (/home/saveryd/Pictures). Xscreensaver has pan/zoom and fade options and I wanted to use them but I guess my graphics hardware wasn't quite up to it as such effects were jerky. I turned all that off, set the time between slide changes accordingly, disabled the Xscreensaver power management function and set Xscreensaver to activate after one minute. The last thing to do was configure Samba so that my Pictures folder was shared over my wireless network allowing me to copy across new pictures on the fly. As this is just a picture displaying box, I have no need for tight security on it so I kept the contents of /etc/samba/smb.conf pretty simple as below: [global] ; Generic server settings netbios name = R3DPF server string = workgroup = R3LAN announce version = 5.0 socket options = TCP_NODELAY IPTOS_LOWDELAY SO_KEEPALIVE SO_RCVBUF=8192 SO_SNDBUF=8192 passdb backend = tdbsam security = user null passwords = true username map = /etc/samba/smbusers name resolve order = hosts wins bcast wins support = yes syslog = 1 syslog only = yes [homes] valid users = %S create mode = 0600 directory mode = 0755 browseable = yes read only = no veto files = /*.{*}/.*/mail/bin/ #The heading below will form the name of the share [piccies] path = /home/saveryd/Pictures browseable = yes read only = no guest ok = no create mask = 0644 directory mask = 0755 I then added a samba user giving the user a suitable password: sudo smbpasswd -L -a saveryd ... and enabled that user: sudo smbpasswd -L -e saveryd A quick Samba restart so the new configuration comes into effect.... sudo /etc/init.d/samba restart .... and my digital picture frame was now contactable from my Windows box by mapping a drive to \\192.168.0.70\piccies or \\r3dpf\piccies (the fixed IP address/hostname and share name I set when configuring the installation). When new pictures are copied into the shared folder, GL-Slideshow will pick them up without requiring any intervention (i.e. no need to restart the daemon or the computer itself). Update 16/11/08 - Bluetooth support. All has been working well in the digital picture frame world since construction six weeks ago. I decided to add some extra functionality to my frame today by plugging in a spare USB Bluetooth dongle to one of the USB ports hidden at the rear of my DPF. This would allow me to transfer pictures taken with the camera of my Nokia E90 directly to the DPF without having to first transfer them to a computer and copy them into place using Samba. Here's how I did it.... First, I needed to install the gnome-bluetooth package to enable file transfers. This can be installed via Synaptic or with the command sudo apt-get install gnome-bluetooth Next I was able to pair the phone with the DPF by initiating pairing from the phone and selecting the DPF from the list of available devices. My default passcode was 1234 however this may vary (check /etc/bluetooth/hcid.conf to see what passcode is set). With the phone paired, I needed a Run box to be available in Fluxbox so I could test gnome-bluetooth. I couldn't find one (and Alt-F2 didn't do anything), so I ran sudo nano ~/.fluxbox/keys and added the line: Control F10 :ExecCommand "fbrun" then I saved changes and restarted. After the restart I was able to open a Run box by pressing CTRL-F10. In the Run box I entered gnome-obex-server and verified that its icon appeared in the task tray. Now I was able to select an image from the phone and send it via Bluetooth to the DPF. By default, gnome-obex-server throws up a prompt to confirm file transfer and saves to ~/Desktop. To change the default save path and get rid of the file transfer prompt I again opened a Run box and ran gconf-editor. By expanding Apps / Gnome-obex-server I was able to untick the Notification box and change the value of 'savedir' to the path that the DPF was using to display pictures (/home/saveryd/Pictures in my case). Finally, I edited ~/.fluxbox startup adding the following line under “Applications you want to run with Fluxbox”: gnome-obex-server & Upon reboot, the gnome-obex-server applet appeared in the task tray automatically. Now I can zap pictures from my E90 at any time simply by using the Send via Bluetooth option on the phone. One last point. |
| Last Updated on Sunday, 16 November 2008 14:25 |