At A Glance Main Projects Tutorials Resume


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Countdown, Audio Trigger, and Light Device

Every now and then in the field I'm lucky to work in, there comes along the need for a crazy custom device. Nothing as crazy as a motion sensing railroad telegraph driver; but the great thing about this project is it deals with high amperage lighting!

Optek OVM12F3R7 light module.

The premise for this device is as follows:

  1. Slam your hand down against a button.
  2. Mega huge countdown initiates on mega huge seven segment displays.
  3. Simultaneously an audio player is triggered to play themed audio during the mega countdown.
  4. At the end of the countdown our high amperage lighting slams on in a blaze of glory!

As cool as this project sounds, it was never deployed in production; but a prototype was made!

A wider shot of the Countdown, Audio Trigger, and Light prototype setup.


A large Kingbright seven segment display.
For the prototype, I only hooked up one seven segment digit, as they take a lot of lines to control. Three would have just been too much with these bad boys; the Kingbright SA23-12GWA 2.3 inch monsters!

Due to the number of lines each seven segment requires, I implemented a MM74HC595M-ND shift register! Using this particular shift register the way I have it configured, I can control a monstrous seven lines with a mere three. What's even better is that if I hooked up all three displays, I could chain these shift registers on the three control lines for giga-loads of control.

A Teensy development board from PJRC.

The brains behind the prototype are the Teensy 2.0 from PJRC. Despite the fact that the Teensy platform is Arduino compatible, I enjoy programming microcontrollers from their data sheets in C...because that's how I started out.

Moving on to the brawn behind the high amperage lighting we find a beautiful MOSFET; the IXTA8N50P-ND. The final number of lighting segments on the project was to be determined during prototyping, so I wanted a MOSFET I knew would handle a lot that could be triggered from our 5V based microcontroller.

It was disappointing that this project never went into production, but it is fun to run the prototype non-stop some days. I am pretty sure my neighbors wonder what the blinding red flashing light is every half minute. The prototype was setup to run in a continuous test cycle to ensure the stability of the system. It has run without problems for over half a year so far!

Charles Palen has been involved in the technology sector for several years. His formal education focused on Enterprise Database Administration. He currently works as the principal software architect and manager at Transcending Digital where he can be hired for your next contract project. Charles is a full stack developer who has been on the front lines of small business and enterprise for over 10 years. Charles current expertise covers the areas of .NET, Java, PHP, Node.js, Javascript, HTML, and CSS. Charles created Technogumbo in 2008 as a way to share lessons learned while making original products.


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