Jun 172012

Last night I started working on a servo tester using the 555 timer. As I am doing more with servos as of late I felt a stand alone servo tester would serve me well in the future. Schematics and board art will be uploaded later in the week when I can finish it and tweak a few things. Today after work I decided I should add a transistor to the schematic for larger servos and loads. It worked. A bit too well in fact. You can see the damage in the pictures below

As you can see the transistor worked. A bit too well. I can only guess at the voltages but it was a bit intense. Loud pops, lots of smoke and bubbled plastic. Its ok I suppose. That servo was starting to annoy me.

Jun 062012

You see them all the time from fresh faced EE students looking to power their new arduinos and LED’s. The simple computer power supply hacked and forged into a fixed output power supply for a range of very common voltages. Which is exactly why I did the same thing. I like my design, rather than trying to cram it all into the PSU case I attached a piece of bent Lexan to the underside of the case and brought all the wires out. I’ve got all the common voltages, and this supply has two different 12v outputs. Later on I may open it back up and throw an LM317 on that second rail for a variable voltage.

I didn’t take any pictures of the bending process but its stupidly simple. Find where you want the bend and add about 1/4 inch (6.4 mm for my metric friends). Then place the sheet in a vice and use a heat gun to heat the joint up. Keep the heat even or the plastic will bubble and ruin. Eventually the weight of the Lexan will cause it to bend at the vice. Just hold it in place for a minute until it cools.