Hi all,

When doing some attempts to make flicker-free coach lighting, I though to take it all one step further and design a car lighting system that autonomously can switch lights in the different cabins of the coach on an off. I also wanted to make something that was less visible than the M* standard lighting kits.

So I came up with a microcontroller design. It’s based around an PIC628 chip, programmed in mnemonic (machine assembly language). This controller has the advantage to be able to drive white LED without additional power drivers. It also has its own internal oscillator, so very few external components are necessary.

The program is quasi-random, that is that I programmed an random-looking sequence of light changes (also with varying wait times) into the programmer.

The challenge, except getting it to work, is installing it in a car. Below, some pictures of that. This is the coach, and Swiss SSB one:




And these are the electronics. Two PCB bars to connect the nine white LEDs, each with a power limiting resistor. On the left the microcontroller, on the right, a voltage stabilizing circuit (5 Volts) and associated capacitors. The rectifier bridge, to connect it to AC, is not present on the version in the photo's yet.



Right, here the electronics go into the car. The microcontroller chips fits exactly in the toilet space, which has a non-transparent window, nicely keeping its interior out of sight. The capacitor (470 microfarad, 25 Volts) occupies the other toilet. The regulator is in the balcony and is almost invisible from outside.





Ok, and below the programming. I wrote a little Excell program, where I enter the light sequency and the wait times. The, the programm creates an HEX sequency that I load into the EPROM memory space of the controller.



At this time, the unit runs from an external power supply, and works perfectly fine now. I did not have the time yet to add a pickup shoe, and run it from the tracks, I hope to do that soon. But I foresee no problems there, as the rectifier circuit delivers a nice steady power to the circuit (much like the circuits in digital loco's are powered, in fact).

I don't think I will adapt all my coaches, too much work really, but it's a nice experiment.

Any comments are welcome!

Excellent project.

Great work Rudi!!!!!!!!
Congratulations!!!!

It's al bits and bites to me!
Great work.
I'm lucky I can access a computer to read all this great stuff.
I'm even luckier "I can read and write"

Very good project indeed!

Perhaps you'd consider productionising your design? I'm sure you'd find enough buyers to make a profit, including right here in this forum!

Luis

Give an EE a soldering iron and some parts....[:o)]

Looks like you are not going to get bored anytime soon!