This afternoon I was without anything to do when I remembered my DK421 project, which had been shoved off into a dusty corner of my hard drive. I didn’t feel like programming any, and wouldn’t know what to do or add anyway, so I got into the hardware side of it.

The Sheets

I dug into Stephanies old room and found the keyboard from the green dinosaur, an Acer computer from the early-90’s. Anyway, I found it, took it to my room and cracked it open. Very simple device really. The keypresses are captured by switches composed of two sheets of plastic, very similar to slide-projector transparency sheets, with tracing on them. When you press the key it compresses a rubber bubble in a sheet and smashes the air, and thus the switch, down and completes the circuit. These connections go to a board with some leds and a chip for translating them into whatever goes down that PS2 cable.

I imagine that a newer keyboard might be more complicated, at least if it’s usb. Maybe not though. I only have so many keyboards to rip open.

Following the tearing apart of the keyboard I hooked it up to my old gateway laptop (it’s the computer I care the least about) and fired it up. No lights, no response. I shut it back down and figured out that I hadn’t reconnected a little black ground that had been hooked onto the metal mounting board as well as one of the pins. If you look at the picture of the transparency-stuff circuit you can see that one pin is connected only to a big spot for the ground.

The Pins

I taped it up and got it working right off the bat. Shiny. I then taped it onto the laptop in the lovely testing position illustrated here. I got a piece of thick copper wire, off of an old power supply, and generously stripped the ends (okay, my father did for me), 1.5″ at least, then coiled each end around a long finishing nail (that’s what it said on the box) and taped it up. This made for a nice, easy to control point-to-point connector for me.

With my newly created tool I fired up VIM and started shorting the pins together to see what they wrote. Okay, thats not true. First I tried tracing individual keys on the transparent stuff, but that got old real fast. It is, however, necessary for finding keys like shift. Regardless, I tried out the good old hunt and peck method, and soon had a list with more than enough keys for the drum triggers. I then tried out the shift key with a piece of spare wire, it works great. Thats an important one, because it is needed for the high-hat pedal.

The Shift Key

Well, thats enough for now. Hopefully the pictures shed some light on the matter if it’s still fuzzy. I haven’t made up my mind on what to build the triggers out of. I almost want to go the air pressure route so the switches won’t wear out to fast. I’ll also have to consider how to build and mount all this, I’m thinking PVC at this point. Off to a good start though :)

I’ve been messing with my 770 some more. Such a sweet device. Here’s a quick rundown of what I’ve loaded up so far:

I’ve also got the stuff to mount SMB/CIFS shares and wrote two small mount/unmount scripts for my home network. It all worked nicely until I tried playing a few MP3’s over the CIFS mount. It didn’t buffer very intelligently, I watched my network monitor on the serving machine and it would spike every time the song “skipped” on the Nokia.

Looking for an answer I hopped onto Synaptic and found a UPnP server, GMediaServer since I knew there was a nice UPnP audio player for the Nokia, from the company itself actually. Hooked that up and it’s behaved so far. Don’t know what I’m going to do about streaming out video to it though. Oh well, I was going to buy a bigger rs-mmc card anyway, I can just dump videos onto that if I need to.

Here’s some screens of the UPnP media player and an XTerm. I greened up the layout with puchi.

My Nokia 770 came today! This one wasn’t bricked on arrival like the last one. I immediately started in on it, and within an hour I had it loaded up with lots of apps from maemo.org. By now I’ve rooted it and have some scripts set up to handle mounting shares from my network. As a bonus I’ve managed to lock up the application manager, an apt frontend, I think I need a reboot to kill off the process. Lord knows I’m not going to try and kill it myself.

Only a few minor complaints at this point. The handwriting recognition is horrid, but the keyboard has a nice feel to it and you get phone-like word completion. I haven’t tried the fingerboard style yet, rugt now I’m writing this with two styluss (styli?) and I’m actually getting rather fast at it. Maye its th qwerty keyboard.

The other pet peeve came when I wa writing my shell scripts in vi and couldn’t find a way to send the escape key to it. I just now realized that there is a hardware back key that would be a likely candidate. Oops.

Okay, I’m gonna reboot her and see about getting descent or doom running :)

So I got my Nokia 770 today, or rather yesterday as it is 3:30am now. Here’s my review on this stunning device.

They shipped me a bricked unit. Seriously, I popped in the battery, hooked it up to charge and came back later. It makes cutesy little start up and shutdown noises, but the screen stays white, occasionally adding in some vertical grey lines for variety once in a while.

The Nokia website is useless, and everywhere I’ve found info on the “white screen of death” on the net, it’s led to the same conclusion: Warranty return and replacement. That’s pathetic. You’d think Nokia would have some quality control, maybe, oh I don’t know, see if their devices even boot before shipping them? The boot cycle is supposed to be very short, and I can’t see the production numbers on a device like this being outrageously high. It doesn’t seem unreasonable that they could check it.

What does seem unreasonable is up to another week of waiting for them to ship me a new one. Stupid. If the replacement isn’t stellar and/or they make me pay shipping to send the brick back to them I will assuredly warn everyone I know away from Nokia. And I’ll be sure to get out and meet some people first so it won’t be an idle threat.

I’ve been looking at PDA’s and laptops on and off for a few months now. I was looking for something simple, and quick to boot. I really only wanted a PDA type device that would give me Wi-Fi connectivity, a way to take notes, and access to a shell and SSH. That’s kind of alot to ask from a simple PDA, and thus I never really found one.

I had given up and decided to just get a laptop even though it was overkill for most of the things I wanted to do. Hibernation mode and a Linux install would get me my quick-booting machine with all the features I wanted. Unfortunately it meant I would have a very large device (compared to a PDA) and it would cost a lot of money.

I started looking back into handhelds the other day. UMPC’s are perfect, but crazy expensive. The lifedrive came close, but it’s expensive, has a kinda-small screen and Linux isn’t quite ready on it. I remembered back to seeing a post on Jon Johansen’s blog (that’s DVD Jon for those who don’t know) about selling a really cool looking Nokia handheld.

I went and looked it up in his archives and found out it was a Nokia 770. It’s (almost) perfect. It has a good and thorough review over at Ars Technica. The specs fit in nicely to what I want. It floats in the middle of the too-weak PDA’s and too-heavy laptops. It also nicely evades the too-expensive UMPC’s at $360.

It runs a patched up Linux kernel too, along with GTK+ for the GUI stuff. That means there is a big developer community who’ve ported all kinds of goodies to the platform. It plays back MP3, Real Audio, MPEG4, AAC, WAV, AMR, MP2, MPEG1, MPEG4, Real Video, H.263, AVI, and 3GP. Whats more you can mount SMB/CIFS or NFS shares and stream from them. I’ll be more than happy to watch movies from my fileserver on the 800×600 screen.

The only real problem I have with it is that the storage space is 64mb. That’s tiny, but it has an RS-MMC card slot good for up to a 1Gb card, so if I need more room I can get it. Plus, it comes with a 64mb card when you buy it, so that brings it to a total of 128mb off the shelf. I have a wicked idea too. Since it can mount shares, why not get the WL-HDD I was going to buy for my hacked ZipIt and just mount that wherever I go? Couldn’t be slicker. Actually it could, but whatever.

So I finally made up my mind and purchased it today. I’ll let you know more about it when it comes, but I’m psyched.