Tagged: hack

Sealed Pet Bowl musical instrument

Every year we have a summer BBQ at work. There is always lots of food, drinks and good fun. This year it was proposed to have an interdepartmental talent competition. (As it turns out engineering is the only department brave enough). So after much discussion we decided that we would perform several individual talents. My talent… musical pet bowls! The Sealed Pet Bowl is the first product I helped develop during my first year at SureFlap. I developed very sensitive proximity/motion sensors that surround the bowl, when it detects something near it opens up. Since I worked on the electronics and firmware I am very familiar with it’s operation and knew it would be quite a simple mod to turn the pet bowl into an effective theremin/laser harp type instrument.


Programming a pet bowl.

To get notes from the pet bowl I took the PWM output normally used to drive the lid and ran it to a small guitar amp. The firmware knows which sensor is being triggered so it was a simple case of making the PWM frequency dependant on which sensor was triggered. Then doing this to 3 pet bowls. Job done, a pet bowl instrument.

Seal pet bowl instrument

The finished instrument in all it’s glory.

Now it was just a case of learning how to play the thing. Time was as limited as my instrument so I managed Ode to Joy. Good performance. Everybody claps. Roll on snare drum. Curtains. You are now looking at the SureFlap’s got (no) talent winner 2016! Video of the performance.

Pet bowl performance

Rocking out.


A winner’s trophy is perfect for holding your beer.

Dead bug LDC1000 inductance to digital shield

I needed to make a data logger to measure the inductance of a coil over time. The coil is flexible and so will distort while in operation. I wanted to know how much this would change the inductance in order to account for it.

I found a nice IC from Texus Instruments, the LDC1000 inductance to digital converter. However it comes in an annoying SON-16 package, so time to whip out the fine tip soldering iron and practice my dead bug wiring. (For various reasons I thought logical at the time (though probably not) I opted not to use the handy eval board.)

So I superglued it onto an arduino protoshield, added a few caps and it was done. To measure the inductance the LDC1000 needs to be clocked, which is what the green board kapton taped to it is doing. This is a breakout I made for the Freescale/NXP KL03 cortex M0+, clocking the LDC1000 at 3MHz. You might ask why am I using the arduino for the logging and the KL03 to clock. Well. Whatever.

I plugged in an Adafruit datalogging shield and a few simple lines of code later I was logging inductance data. Sweet.

dead bug.png