These are fun projects mostly in the physical world that counterbalance my econometric research. They are mostly related to programming Arduinos or things that go boom or ffffffsssssht.

Powered glow-in-the-dark planets

Waterstones and many others sell these little planets that glow in the dark and make for an interesting ceiling feature. But wouldn’t it be nice to light them up properly? I bought a few components and spent a few hours connecting them. I am quite pleased with the result: I used 3mm warm white LEDs. … Read More

Sparkling night launch

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Flax crackers - Gluten free and low carb

This recipe is for gluten-free and low-carb flax crackers. They are also free from lactose, so you may be wondering if there are any ingredients at all. Yes: ground flax seed, ground almonds, egg, rosemary, salt, water. The difficulty with crackers is how to spread the dough, so read on for a solution. Add some … Read More

Night launch with new launch pad

We improved our previous Gardena-based launch pad by switching to a launch tube design. Since there was plenty of wind, we did not bother flying with a parachute but made a nose cone from a piece of foam which we wrapped in cling film, plus a small piece of play doh at the tip. This worked … Read More

Adventures in etching

This is my very first attempt at etching my own PCBs. My goal was to design a two-sided board to hold four 256K serial EEPROMs (24LC256 Serial I2C EEPROM). The PCB is about 5cm long as you can see from the 0.1″ pitch. The lesson I learned was about using the correct paper to transfer … Read More

Water rocket

Building a water rocket is a great family activity. We used the DLR’s excellent instructions for a water rocket [pdf], a launch pad [pdf] and flight evaluation [pdf] to build and launch our first 1.5L water rocket. We pressurised the rocket to 5 bar and achieved vertical distances of about 40-50m (guesstimated, since all our … Read More

MPL3115A2 Altitude Sensor One Shot Mode

The good people at hobbytronics sell a neat altimeter based on the MPL3115A2 pressure sensor. Its datasheet mentions a one shot mode, which can be a practical solution if one needs a high data acquisition frequency. For some reasons, I did not get the FIFO polling mode to produce new readings at intervals shorter than … Read More

USB-OTG cable for Arduino Uno

Wouldn’t it be nice if you could hook up your Arduino to your Android tablet and use it as a command/debugging interface like ArduinoCommander does? If you want a USB connection instead of bluetooth, however, you will need to find a USB-OTG cable. This is because Android devices usually come with cables that treat those … Read More