A while back, I made a very small AVR programmer, based on [simpleavr]s vusbtiny programmer. Even while I was working on that board, I became annoyed with the fact that more than half of the board was taken up by the USB and ISP connectors.

(more…)

When I couldn’t figure out a way to add a monitor to my kitchen, I designed a simple little laptop holder to hang on the kitchen door.

On one side it has two pockets, one on the front, which fits the lower half of my laptop snuggly. The other pocket is on the back. Originally I planned to fit a wooden board in there, to stabilize the holder and keep it from tipping forward. However this doesn’t seem to be necessary, so now it serves as place to store printed out receipts.

(more…)

My third biggest fear in life is having my laptop play a loud startup sound in a quiet library or crowded lecture hall. It comes right behind my fear of moray eels and small pebbles.

To address this serious problem, I made myself a small hardware mute button for my keychain.

(more…)

The last step in my PCB design process normally is the silkscreen. When I try to design a nice helpful silkscreen, I often find my self wondering “How small can I make the text?” or “If I put this text over a via, will it still be readable?”. Usually I end up digging around some old designs to find some examples of what worked, and what didn’t.  But during my last run, I got a bit annoyed and decided to include a small reference board for the most  common situations.

(more…)

Sometimes you just need one more input button or switch.

There are many different ways to use you existing pins more efficiently. If you still have a free analog pin, you could use a resistor ladder to connect multiple buttons to one pin. Or you could use a key matrix to drastically cut you pin count for many buttons. However, if you only need one or two additional pins, here is a neat way to connect 1.5 buttons per input pin.

(more…)

I always like a challenge, so when I saw [simpleavr]s vusbtiny programmer, I started to wonder how small I could make an AVR programmer. All in all I’m pretty pleased with the result.

The schematic is almost the same as the original one. I only added a LED an resistor to indicate a proper power supply.

(more…)

Recently we suspected that one motor of our hexacopter had been damaged in a crash. Since removing the motor requires almost the complete disassembly of the copter I started thinking of ways to test the motor in place.

The most important parameters I was looking for were the speed of each rotor relative to the others, and the consistency of the speed over several rotations.

(more…)