Building a discrete digital-analog-converter

Want to take back control of how your digital audio files become sound? One thing you can do is to build your own digital to analog converter. This one is made from discrete components, centered around a resistive ladder. Yes, there are a couple of integrated circuits in there which are used for demultiplexing the incoming signal but the magic happens in that R-2R network. The project is an interesting read and makes a point of looking at the issues raised when trying to precision match resistors. Apparently it can be done with 0.1% components if you have a lot of them and a multimeter that can measure down to seven decimal places.

[Thanks Bigbob]

Ride fly: Segway DIY

The video above is the final working DIY Segway from [sb-scooter]. The website and build log don’t have a lot of information at the moment, but you can still gawk at several pictures of the construction (and a picture is worth 1000 German words).

For those looking for the nitty gritty, with some quick math we figure its two 500 watt motors, powered by 12Ah batteries, will last about 90 minutes. If you’re looking for more details or to build your own, you’re as lost as we are.

[Thanks Panikos]

Negative laser etching

[James] has been refining a method of negatively etching metal with a laser. He had been using a product called Thermark which is designed for this process, but it’s quite expensive. He found that paint designed for wood stoves works just as well. To prepare the surface he bead blasted it and then cleaned of the residue and finger prints off with acetone. The board was preheated in an oven before covering it with the spray paint. He ran the laser at 98/100 power and 90/400 speed at a step size of 0.1mm to achieve the results above. This should immediately make you think about making circuit boards. We’d love to ditch the toner transfer and we’re always looking for one more reason to get a laser cutter.

A desktop made of Air

Deskbook Air Guts

[Bart] managed to get his hands on a Macbook Air for free. The catch was that the monitor hinge was broken and the laptop wasn’t in too great of a condition. Rather than scrapping it or using it as a cake cutter, he decided to turn it into a keyboard PC. By removing the internals he was able to fit all of the components with minimal modification. [Bart] has added a few things to make it a functional desktop, such as integrating a USB hub under the the keyboard and fitted the keyboard with a Magic Trackpad. As with any great hack, the project is still in progress, and we can’t wait to see the final touches as it comes together.

Repairing the Itona VXL thin client

[Jim] was the happy recipient of 11 non working Itona VXL thin clients. The units he received were 800Mhz CPUs with 256 MB of Ram and 256MB of storage. None would power up. Upon internal inspection, he found a common theme. Leaky bulging capacitors in the power supplies. Since these came with custom 50W power supplies, he opted to simply replace the caps instead of replacing the supplies themselves. Now he has 11 fully functional units. There are great pictures and lots of info on his site, but what he doesn’t talk about is what he’s going to do with them.

Why don’t you pop on over to our Hacker Q&A and tell us what you would do with them.

Super simple Arduino setup lowers electricity bills

An Arduino with 40 lines of code, a temperature resistor, and servo are all that’s truly needed to save some dough with this thermostat by [Peter Hamilton]. LEDs and a potentiometer are added as well to help set and read the desired temperature. With or without said additional parts, the hack is still ridiculously simple and we’re wondering why we didn’t have a similar setup on our blisteringly cold office AC system before seeing it.

Though, we’re going a bit further with our version, plans are in the making to add timers to turn off the system for extended hours while no one is at the office. What would you add?