Friday 8 June 2012

Productive Fortnight

Having a 4-day weekend is a definite recipe for hobby productivity...

Over the Jubilee weekend/week I managed to push forward a number of projects, including; the OO scale card modelling, the RC dual-motor controller and a couple of new projects.

One of the new projects is Arduino based and makes use of the output channels to control scale lighting on my forthcoming OO layout. The idea is to simulate a day in scale speed and loop through a list of lighting circuits which have start/stop times - as the time is reached the lighting circuit is either faded up (PWM outputs) or flickered on (in the style of fluorescent street lights). I want to avoid building too many circuits (555 timer etc), as the programmable nature of the system gives me the flexibility to tweak and change the lighting as desired (without having to fix on/off times etc with resistors/capacitors).

The main code function is a loop, so with a scaled pause and incremental counter, I can approximate a 24 hour day in whatever time base I want. I could use a potentiometer to dial-in a scale, or I could fix the scale in code. I'll define a number of lighting types, which will define either an analogue/PWM control or a digital control of the circuit - the PWM will allow for fading and the digital for simulating fluorescent and regular tungsten. I can also go ape-shit on the lighting with backlit billboards, building signage etc and funky lighting effects.

My plan is to also use an interrupt channel in order to reset or tweak the playback (perhaps skip an hour etc), that'll enable the loop to be broken and the interrupt code to be executed before the loop resumes.

No code written, but lots of notes and ideas on scrappy bits of paper. When I get a few minutes I'll start sketching out the code. The main issue is devising a template way of driving the lights - I'm thinking of using LEDs for most things, so each channel will need to power a handful of mini-circuits.

This started off the back of me wanting to simulate welding flicker - something I still want to model and may perhaps execute with this approach (probably a little overkill for an Arduino however). Another project on the list; just what I need!

The card models have come a long way - I've virtually finished the low-relief workshop and moved straight into building the concrete bridge. With that finished (sans a few bits that need to be assembled when I know the exact layout of the bridge) I moved onto two new ones; the inspection pit and the small goods store. I've modified both slightly, as I wanted two inspection pits out of the one kit and the small goods store didn't work too well with the type of card I'm using, so some extra glue joints and cover caps are needed there.

The dual-motor controller is an entirely different matter and deserves it's own post...

On a side-note, I did get to see the Queen.