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So for anyone looking for an update on the Steampunk PDA: It’s dead. I was building it so that I would have something to sync with Outlook and remind me of appointments, tasks, etc. Well, the company gave me a Blackberry, so I now have no incentive to finish the PDA. Would it be cool? Sure. Would it be cool enough to entice me to finish it, even though I already have something that works? Probably not, but maybe someday. Who knows?

My next project is an automated sentry gun for the Defconbots competition at Defcon in Las Vegas this year. I was going to build a level 1 sentry from TF2, but a buddy here at work is already doing that. So…. I decided to one-up him and aim for a level 2 sentry.

Yep, complete with dual, counter-rotating gatling guns. I have picked up a few parts, enlisted a partner, Nate, who may be posting on the blog later, and even made a gatling-esque paperweight on the CNC mill:

Sorry about the image quality, I took that with my cellphone this morning.

I received the display (no pics yet :’( ). It is teeny, but the contrast is really nice. Last but not least, I just finished the routing of the PCB and should be sending it out for fab at BatchPCB by Friday.

I have three “airwires” left. The auto router choked on this board, so this was the best I could do manually. I added some vias so I could solder a jumper in to connect the nets.

I haven’t been working on the Pocketwatch much because I am waiting for the display, and I have been rather nervous about constructing the encoder/switch with my limited mechanical abilities. But tonight I was putting off starting the last Harry Potter book (Don’t tell me! I haven’t read it yet! *fingers in ears* NAH NAH NAH) and I decided to head into the lab and fiddle around. I ended up picking up the pocketwatch and constructing the switch mechanism. It actually turned out rather well, nice and smooth, not wobbly. It still needs finishing, but here it is:

The tiny disc magnet is glued into a slot in the plastic shaft on the left. The bushing is made from a drilled out and turned down 2-56 nylon standoff. Pressing down on the shaft engages the tactile switch with a satisfying *CLICK* and spinning the shaft will cause the hall effect sensors to sense the rotation.

The encoder started as a sketch:

Then Prowler50mil on the Steampunk Tactile forum suggested using one magnet and two hall sensors. Great idea! I built up a demo to try it out:

Lo and behold, it works!

I ordered the OLED last friday. The US distributor was out of stock, so I had to order from Australia. Here is a 1:1 mock-up I did to get an idea of the display size:

I spent quite a while on Sat. night grabbing pics of pocket watch dials from eBay and resizing them.

I went to the local antique fair today and found this pocket watch case for $5:

I have also started a power budget:

Power Budget

The good news is that I found a 300mAh battery that fits in the case along with the electronics, so I should get 4.7 hours of runtime and/or 18 days on standby before I need to recharge the battery.

There is a demo of the 128 x 128 OLED here. It has the same drivers as the 96 x 64 version that I am using. Check out the unicorn animation near the end. I am hoping I can animate an imp and have the option of having a Dis-organizer.

I decided to spend a little more time planning this project than I usually do (a stitch in time and all that…), so I started some design documents on Google docs:

Feature List

Schedule

Hopefully this will help keep me on track a little better, and avoid scope creep.

While I have been thrilled with the success of the 128×128 LCD, I happened upon an oLED display today that would allow the whole thing to be miniaturized to the point it would fit in a pocket watch:

I am having so much fun with this PDA/Tricorder project! Although the 128 X 64 mono LCD is cool and all, I just had to buy the 128 X 128 color LCD from Sparkfun that I’ve had my eye on. I wired it to my ATmega128 breakout board and powered the whole thing with my STK500 set to 3.3V

Voila! I had a nifty color LCD for my project. Here are a few screenshots:

I also picked up a few Hammond electronics enclosures ( I love electronics enclosures! I collect them…) from Allied. I get a great deal through work, plus free shipping. I got the 1553B and the 1455J1201. Of course I am also considering putting the electronics into an actual tricorder case. I bought a scratch-build kit from GMProps (look him up on the tricorder props forum), but it proved to be too much for me. Maybe I’ll try a Playmates Tric from Ebay.

I have been struggling for a while with the lack of user input on the PDA project. I had considered adding an interface through the RF transceiver, but that would mean I would need to be near a PC. I have been unable to find any pushbuttons that I like to install on the face. So I did the next best thing. A sharp sideways tap on the right side of the enclosure brings up a menu, with a small circle next to the selected item:

Tilting the unit in the y direction moves the selection circle, and another tap selects the item. It still needs a bit of tweaking. It seems much easier to tilt in the x direction, because I tilt the unit towards my face when looking at the screen, and that makes the selection circle move down the llist.

Here are links to a few thing I found during my research into tiny user interfaces:

• TiltType: An Accelerometer Based Text Entry Method
• Sensing Techniques for Multi-Device Interfaces (PDF)
  
• Shake Them Up! A Movement Based Pairing Protocol
• Bringing Sketching Tools to Keychain Computers with an Acceleration-Based Interface
• GUI Development: Embedding Graphics Part I Part II
• Variability in Wrist-Tilt Accelerometer Based Gesture Interfaces
• Detecting Freefall with Low-G Accelerometers,Measuring Tilt with Low-G Accelerometers