Leapfrog Didj: Handheld Linux On The Cheap

Today our good friends over at Woot! are selling the Leapfrog Didj, a low cost educational toy aimed at little kids. Lucky for hackers out there, the Didj is actually a linux device, and gaining serial console access is as easy as soldering two wires. The documentation out there is a little outdated, with a number of broken links and stale wikis, but $25 for a portable linux device is a hard deal to beat. A list of sites which might be helpful are listed after the break, as well as the hardware specs of the Didj.

Let us know if you have played around with hacking the Didj before, and if you have any tips for other readers. Don’t forget to tell us what you do with the Didj as well!

Thanks to [Mark] for the tips and the hardware details.

(Possibly) Useful links:

Hardware Specs:

* Processor: 393 MHz Arm 9
* Display: 320×240 resolution
* One 24-bit 2D layer (no hardware acceleration)
* One 16-bit 3D layer
* One YUV video layer (no hardware acceleration)
* Graphics: API OpenGL ES 1.1–A reduced instruction set version of OpenGL for embedded systems
* Main RAM: 32 MB DDRI 131 MHz
* NAND Flash: 256MB for data storage/download content
* Media Cartridge: 64MB
* System Software: Brio–Firmware is built on an abstraction layer called Brio to make OS and hardware transparent to developers. This means all software must be ported to Brio to run on this device.
* Screen LCD: 3.2 inches, 16.7-Million Color TFT

64 thoughts on “Leapfrog Didj: Handheld Linux On The Cheap

  1. @Asuraku,

    Woot is a reseller, generally they buy up excess amounts of items, either refurbished, overstock, clearance, etc and sell them one item a day.

    They always list the condition (New, refurb’d, etc). Usually they get discounts when a store/chain doesnt want to sell the item anymore, and just wants to offload the merchandise.

    I would recommend reading their FAQ if you want more info:

  2. It looks like a cool little hack toy

    it also looks like what little scene there was died 2 years ago, and the most progress that was made was hooking up the serial port so you can poke around in its underbelly

    If there was a active scene, with more progress and maybe even a sdk I would jump all over this, but with a 2 year old dead scene, and nothing much else besides ssh-ing into it, I have to pass, it really doesnt seem worth the effort

  3. Just ordered mine, I really need to start checking woot more often!

    There is a lot of possibility here, depending on the firmware you could get a more relaxed distro on it and really have some fun. War-walking and GPS are just two small modules away.

  4. The GP2X is far more hackable has a SDK. This half hacked toy is not worth the effort unless you have days of time in mom’s basement to get to where you can be in 30 seconds on one of the open linux handheld gaming platforms.

  5. I purchased one of these recently for my daughter. It’s aimed for late elementary school kids. The software as it is allows for a lot of transparency as to how she is doing on an educational level.

    Of course, in a few years when she outgrows it, I now have a project device.

  6. @fartface

    Chill out, this is $25, not $150. If it’s 1/6th as good it will be worth it.

    I bought one!

    I just hope that its easy to get an NES emulator on this thing. Anyone know? I just started clicking the links.

    I would imagine we’ll have a lot more hacks after today on this thing!

  7. I’m guessing the Didj hacking scene died out because these were relatively expensive to start ripping apart- I wouldn’t be surprised if the woot offering brings the scene back from the dead.

  8. Didj How to Extract Files
    From eLinux.org
    Jump to: navigation, search

    Download http://download.leapfrog.com/leapfrogconnect/PC/didj/DidjPlugin.exe

    * Get the v1.2 tarbal from http://www.cabextract.org.uk/
    * extract it
    * run ./configure
    * run make
    * copy the bin somewhere convienent like /usr/local/bin
    * cabextract -d test DidjPlugin.exe will put all the extracted files in the test directory.

    The .lfs files are really .zip files inside

    Mount the rootfs.jffs2 somewhere convinent and do a ls -lR >files this will give you a list of what’s inside.

    Hack away!!

    BTW here is how to mount the rootfs.jffs2 image onto the temp directory:

    * modprobe mtdcore
    * modprobe jffs2
    * modprobe mtdbig
    * modprobe mtdchar
    * modprobe mtdblock

    * dd if=erootfs.jffs2 of=/dev/mtd0
    * mount -t jffs2 /dev/mtdblock0 temp

    You must have all the modules for your distribution of choice

  9. +1 for “cool, I wish I had something to use it for”. No built-in wireless, so I can’t have it “control” anything; no commodity memory slot, so I can’t have it read/play/view any sort of media. No analog input / touchscreen, so your input vocabulary is pretty limited. I *want* to want to hack one of these, but I come up with anything that sounds like a good idea.

  10. Just a heads up to those that ordered from woot and have not experienced their shipping yet. Usually you would get your item in about 1.5-2 weeks but they just had a long woot-off and so they may be slightly behind on shipping so it may take about 3 weeks till you get your goods just so you know unless you 2 dayed it.

    And they use smart post which is another reason.

    enjoy your items and post how it turned out.

  11. I want one, but how do you transfer files to the device? USB?
    any possibility of ‘shoehorning’ a wireless usb extender or bluetooth?
    that would open alot of possibility’s

    other than that, i cant see much use other than games, but then again there are easier platforms for this purpose.. i think.

    maybe some nice spare parts?

  12. Looks like Claude Schwartzs Gerbers could be run at BATCH PCB and get Me a set of SD cartridges for hacking. I got two didj’s from woot. So by the time they arrive from snail mail. I can have the batch PCB’s here as well.

  13. Nice to see the Didj gets interesting for other hackers as well.

    Sure , the gerbers should work at any PCB manufacture. No fancy drill sizes or line widths are used. But the FT232R footprint is not easy to solder by hand.

    I already ported over a library (libcastor from Orkie)from the GPH Wiz which handles graphics and input. So emulators are doable , most of the stuff which runs on the GPH Wiz *should* work on the Didj as well.

  14. For those of you who want a linux handheld but maybe something with a bit better community, check out the zipit wireless messenger (version 2). It’s like $50, has an SD card slot, and wifi. And I think already has emulators ported.

  15. I am working on remaking his board using the FT232RL SSOP28 (which is easily soldered with flux). But at first I am going to make a single sided board that I can etch myself without the nand.

  16. A follow up. What’s everyone using for their development? I use Slackware and I suspect that the kernel versions and the matching MTD drivers are out of sequence with the Wiki that came up later.

    The Didj wears a USB Mini-B connector already.

  17. Just to let people know we have a active wiki going at: http://www.elinux.org/Didj
    I have posted an eagle library for the cartridge pins and have posted a eagle board file that works as a breakout board.

    I just made a breakout board I didnt use the FTDI chip mainly because I needed a quick breakout board and the final board wont even need a usb it will hopefully just need a microsd.

    It cant play roms yet but that is one of the goals of the project.

    The diji already has a usb slot and if you know what your doing you can get to some of the internal storage with it. The wiki has some instructions on this.

  18. @Awesomenesser

    Great! This is exactly what I need to get started! I tried to massage the Altium Designer stuff into eagle with no avail. With the eagle library we all can just make whatever cartridge we need! I’ll probably start with a SD (maybe micro) and USB serial. Eventually I may look into putting a RF transciever (Like the Micrel MICRF600 series), high-density flash for the OS, and SD for datalogging.

  19. @hpux735

    Take a look at that cartridge I made because its really easy to make the cartridge lock in like the real one. My goal is to make the pcb like 5mm inside the slot then I am going to sand down a block of plastic and super glue it on the edge of the pcb inside the diji then when the cartridge is in the digi it will look like a real cartridge. I am going to do this with a microSD inside because one we get everything working we shouldn’t need the serial anymore.

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