During my siren project I spend some time checking out the products at both Whelen Engineering and Federal Signal Corp. Both companies also have lots of traffic advisor products so I figured why not try building a light bar driver.
The patterns I used are pretty much the same as the pro equipment. But it is easy to create your own pattern and if you are using an EEPROM instead of a old annoying EPROM the changes can be made quickly.
The final code can be found here. On the first page the actual code is found and on the following pages the patterns I selected are seen.
The circuit is very simple. I used a 27C512 for the final design because I have a lot of those around.
A short description...well the EPROM holds the program and the output of the EPROM is connected to the LEDs. If you want to use a big light bar on top of your car these outputs can be buffered so it can drive high power LEDs. The light patterns are programmed into the lower end addresses (A0-A4) and the upper end A8-A11 are used to select a pattern. U2 is a binary counter which just counts until it reaches Q6 and resets the counter. To generate a clock for this counter I used the simple 4093 oscillator and the spare NAND gates have been grounded so they don't make any trouble. Since the EPROM runs on 5V a small regulator (U4) has been added.
A short video of the light patterns can be found here. And below are some pictures of the complete circuit.
I have been watching some more videos and have made some new patterns. Here you can see the new patterns. And maybe I will build some kind of bar with some high power LEDs...maybe.