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.
Okay ladies and gents, here’s a Chasing Light project using a single Shift Register (74HC595) and a TI Launchpad. (I’m currently following a line of research using the Shift Registers, but there is an easier way to do this with just a Launchpad alone.) It can be easily adapted for many uses. Examples include, but not limited to:
- Theatre Signs
- Airport Landing Strip
- Eat At Dave’s Signs
This particular Launchpad project uses an external device called a Shift Register. Simply put, it’s a device that remembers the 1 or 0 you just put into. If you put another 1 or 0 into it, it shifts all the existing saved 1’s and 0’s over one slot and adds your newest value in. It can hold 8 values, hence the term 8-bits.
Here’s what it looks like when its all put together on a breadboard:
Chasing Lights v1.0 from claymore1977 on Vimeo.
The lightbar project work continues! All the proper ohm value SMD resistors *finally* arrived in the mail, and a few short evening work sessions later, the resistors are in place, dud LED light modules replaced and leads carefully soldered in… we have an operational Lightbar!
Now, the front 3 Red and 3 Blue are electrically different than the rear 3 Red and 3 Blue, so add in the working center takedown and 2 alley lights, there are 15 independent LED modules on this bar. However, the software that was on the MSP430 I hooked them up to only was written for the front 3 Red and 3 Blue only, so the bar is not flashing at its full potential…. yet!
Here’s a short video that’s a bit out of focus. I didn’t catch the focus issue when I uploaded it because it was well past midnight 🙂 Once I update the software I’ll film a higher quality version.
1:24 Model Whelen Liberty Police Lightbar from claymore1977 on Vimeo.
Here is a project idea for some of you. If you are anything like me and you are experimenting with an Arduino or TI Launchpad for the purposes of your model railroad, then you likely find yourself adding and removing LEDs and associated resistors to/from breadboards over and over again. So it dawned on me: Why not solder some LEDs and appropriate resistors for a 3.3V source onto a spare PCB project board and slap some headers on there? Well, since I was waiting for some parts for other MSP430 projects, I did just that!
So it dawned on me that the TI MSP430G2 Launchpad Evaluation board isn’t very small and probably wouldn’t fit in any models smaller than G scale. I also realized that buying a bunch of the Launchpad Evaluation Boards at $10 is still cheaper than other alternatives, but not as cheap as buying the raw MSP430G2 chips by themselves (MSP430G2553 is about $2.50 for just the chip). Therefore I set out on an endeavor to figure out how to minimally power an MSP430G2 chip without the Launchpad Evaluation board.
Turns out, it’s ridiculously easy.