The Rusty Spike

A Railroad Fan's Website


Completion: 1:24 Model of a Whelen Liberty Lightbar

And that’s a wrap. Well, almost. I need to bump up the amplification on the headlights and decal the model, but other than that, it is finished! The entire point of the exercise was a proof of concept on an accurate modern emergency vehicle lightbar, and boy oh boy did I learn a lot along the way. I’ll list those things after the video.

As the prototype of what is sure to be many incarnations to come, I dub this ’07 Ford Shelby GT500 my ‘Demonstrator‘! Please ignore the 8xAA battery pack on the side. Normally, this car can be powered by a 9V that fits nicely into the engine compartment, but I was plumb out of 9V batteries. Yes, there’s some in the house smoke detectors, but Murphey’s Laws have taught me a thing or two, so I left those 9Vs where they were 🙂 Anyways, using a 8xAA power supply tested the circuitry against a 12V source, so it’s all good! Enjoy:

Demonstrator: 1:24 Model Whelen Liberty Police Lightbar from claymore1977 on Vimeo.

Lightbar Features

  • 6 Red, 6 Blue, 3 white lights on the bar, all independently controlled.
  • 2 headlamps, 2 Tail Lamps, all independently controlled.
  • IR control, pushbutton backup.
  • 25 main bar flash patterns, 8 traffic advisor patterns, 4 headlight/tailight patterns, but the chip has room for up to 180.

Lessons Learned

  • Flux makes soldering much easier, especially tiny things, but also can make a big mess. Prep for flux clean up if you use it.
  • Magnet wire is great for tight spaces, but it requires lots of prep to make it solder well.
  • Build the entire circuit on a breadboard first, not just pieces/parts.
  • Part Number: 7805 (5V voltage regulator) gets amazingly hot for passing <150 milliamps off a 9V battery. Plan accordingly.
  • MSP430 chips have a hard time driving some of the LEDs that require a Forward Bias of ~3.0V. If you’re powering the MSP430 directly off of 2 or 3 AAA/AA batteries, 3V LEDs will stop working well before the MSP430 does.
  • Double check the solder connections prior to install. Check them for resiliency against physical stresses as well as electrical conductivity.

Leave a Reply

Your email address will not be published. Required fields are marked *