IN-3 Matrix is nearly there
It’s been a long time since I wrote any updates about my IN-3 matrix project. Whilst I haven’t had much chance to work on it it has come a long long way from the original 4×4 tester.
I built an oak frame, machined an mdf board and attached 128 bulbs. Then I started the long process of wiring up each bulb to the PWM driver boards. In hindsight, I should have designed some kind of PCB strip to connect the bulbs to. This would have saved many hours of labour and been a lot neater. As it is each row of 16 bulbs takes about 1 hour to wire. Very boring so next time I know what to do!
I opted to buy a high(ish) voltage supply from eBay, the display can draw a lot of power when fully lit so despite having literally hundreds of high voltage driver boards for my IN-9 kit I figured to play it safe!
I am still only running some test code to make sure the bulbs light up and in the right order. I’m using an Arduino and the Adafruit Adafruit_PWMServoDriver library to communicate with the PCA9685 PWM drivers. Once I find a couple of hours to finish off the last two rows I’ll focus on what to use as a controller (probably the Teensy I’ve had laying about for 3 years) and actually write some proper firmware.
I’ve also now added a Github repo with all the hardware design files (DesignSpark PCB) for the driver boards and arduino sketches. I’ll continue to add to it as I progress.
Nixie Matrix prototype ready
It was a pretty straightforward task to assemble the bits into a functioning 4×4 nixie matrix. The tubes are mounted on spray painted black MDF with the PWM driver mounted on the back. They are each held in place with a small square of double sided foam tape. Wires soldered on the back to the tubes create a small nest and will be more neatly managed of the bigger version. I programmed an Arduino with the Adafruit pwmtest example and it all works fine. In fact, it works much better than I expected and I think I’m ready to go full scale, with no real modifications. All seems too easy.
I did a measurement of power consumption and the 4×4 uses a power of 1.8W, so will need about 15W for going full scale. Not too bad really for 128 tubes.
Nixie Bargraph Clock
The new boards have arrived and it looks like we have a winner. Now time to write some firmware….