Category: Uncategorized

SMD prototype boards

I have frequently had the need for a SMD prototype board, and while regular strip board can work it is never satisfactory. After spending £15(!) on 1 small board from Farnell for work I decided enough and quickly designed my own. The boards arrived this morning. I haven’t made anything with them but I might knock something up later, see how good they are… I’m not convinced by the yellow…


Nixie clock is finally finished

It’s been a long time since I started the rework of my nixie bargraph clock. Probably about a year, but I can finally sit back and say it’s finished. I plan to make a few, one to repair the original instructable clock and this one which I mounted on a piece oak.

The numbers have been laser etched with the tubes held by copped pipe straps. The board is mounted on the front with a protective acrylic screen. Exposed PCBs aren’t to everyone’s taste but they are mine. There’s a little RGB LED which indicates which mode the clock is in: set time, calibrate hours tube, calibrate minutes tube. Knowing that the tubes have a limited life span I added some code so they turn off between 1am and 6am. All pretty straight forward stuff. Now it hangs on the wall looking ace.

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.

Nixie board V2.1 ordered

The clock has been running for a week now without fail* so about time to order the next, and hopefully last, rev of the board. This time in white with no silk. What difficulty there will be in soldering will be made up by the pure sexiness of the board…

*ok one fail. The smd inductor I was using was under rated and burnt out after 12 hours. Since then it’s been fine.

Wave carved coffee table 2

After my first coffee table I was commissioned to make a second, this time using significant dates. Birthdays and longitude and latitude numbers were incorporated into the underlying equations that generated the rippling function. The function was carved in three panels into a beach worktop. The table was finished with hairpin legs and a coating of Osmo polyx-oil.


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