If you don’t have any way to output information, debugging projects can get annoying very quickly. Often you can help yourself by blinking LEDs but one of the most popular method still is “printf-debugging”.

Since I tend to slim down my projects as much as possible, I often end up with microcontrollers without built-in serial communications. There are a few software UART libraries around, but those are normally fully featured implementations and need timers or interrupts.

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Circuit boards come in all shapes, sizes and colors. There are many reasons why you might want to swap the standard green boards for something more exciting. It might be to simply make your projects stand out more.

Dangerous prototypes are quickly identified by their bright red color, genuine Arduinos are always blue and the Lilypad is a lovely lilac.

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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.

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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.

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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.

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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.

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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.

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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.

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