AVR LED Game project

[David]’s been building his own game platform based on an ATMega chip and an eight by eight LED matrix. Looks like he’s used the project as an excuse to get familiar with eagle and doing his own PC board design. Even if the game doesn’t really interest you, future project designs can probably benefit from his roadmap.

No laser? Get your laptop etched for free!

Want to get your laptop custom etched… for free? During the next couple of months, I’ll be giving away some free etching sessions. How do you get one? Just submit a fresh new hack via the tips line. If it makes the cut and gets published, you’ve got a chance to get your laptop or gadget etched in this 45 watt epilog laser cutter. Here are a few guidelines to help you win:

  1. Make sure it’s fresh. Use google for 10 seconds to make sure it hasn’t been published on a major blog already.
  2. Make sure it’s got a picture – everybody likes a good visual aid.
  3. You’ll be more likely to win if you’re submitting your own work.

Good luck!

Plumb in your espresso machine (cheap)

A while back, I wrote up a how-to on some mods I made to my ECM Giotto espresso machine. After giving it some break-in time, I finally wrote up my cheap plumbed in espresso trick. Plumbing kits use a $50 solenoid that requires special plumbing. My version uses a $12 fridge solenoid, easily adds on to my previous mods, and only requires some tubing size adaptation.

li-ion for your roomba

[gim] gutted some li-ion laptop batteries to replace his roomba’s battery pack. He had to pick up a li-ion charger and add a protection circuit to deal with the li-ion cells, but ended up with a new lighter pack for his roomba. If you head this way, the protection circuit is a vital component to prevent fires/explisions/etc. Looks like a great resource for robot power or even R/C projects.

M3 headphone amp

If you’re serious about your headphone amps, you probably already know about the M3 headphone amplifier. Instead of going for the extra tiny, they’re going the ‘screw the size, it’s all about the sound’ route. Thsi thing needs a 24v .5amp power supply. Boards are available, and the discussion has gotten so long on headwize that they exceeded the maximum thread length.

I got busy with the laser last night and came up with something new: a custom etched track pad. It still works, with a bit of added texture where I introduced it to the warm glow of the laser. Hit the link for pics and a walk through.

Contactless voltage detection

[Tim], builder of that sweet NES pad controlled Silvia espresso machine put up an interesting idea for voltage current monitoring – at least, for AC circuits. In a nutshell, he created a mini transformer by wrapping some wire around the outside of one wire of an insulated AC power cord. Espresso machines use 120/220VAC actuated solenoids, so that’s why he’s so interested. I love the idea, since the detection circuit is just a piece of wire.

Underwater GPS (sorta)

Since water blocks the radio frequency used for GPS triangulation, GPS is considered pretty useless for SCUBA divers. Apparenlty some of them are finding it useful to waterproof off the shelf units for tracking the beginning and end of dives. (Dives in open water often involve currents that can really move you along.) To avoid any wiring, a floating case is used. When the diver wants to grab a waypoint, he/she lets the gps surface for a short while to acquire a fix. Then the diver can pull it back down and mark the waypoint or record the coordinates.