Whatever my track layout will be (still thinking about that ), it'll need some points. But this time, I've decided I shall NOT have a tangle of wires under the board! Even on a small layout, tracing wires/faults/feeds etc can be a right pain in the neck!

So the plan is to have one pair of wires to feed DCC everywhere, and another 4-wire cable to feed digital point control using i2c or similar control. Although I've a collection of old Peco point motors, I can't say I've ever been keen on their 'snap-snap' whether using AC pulses or DC capacitor discharge. Reading through many threads and blogs here, it seems servos are a good way to go.

Suitably encouraged, I sent off for some servos, an Arduino nano and some I/O expanders. Actually, they are cheap clones because I've no idea whether it'll work out or not. Then I threw the lot together on a breadboard, cobbled some program code together, and this is what I have today:

Now I should admit here that I have a background in electronics and IT, so doing this wasn't at all fearsome! However, I am amazed how easy it is to put the pieces together. The Arduino libraries cover a huge wealth of functionality, so it's really a case of integrating the parts with some C code statements and testing. The nano is particularly easy to use because the USB interface makes uploading binaries a doddle. What have I been missing?!

The outline design is thus:

Not very elegant, but I hope it gets the idea across.

So far, 15 switch inputs are working on the nano - the maximum that can be configured without input multiplexers or shift registers. My expanders are actually 16-way, but they were cheap and had easy-to-use libraries available. So here's hoping these boards will fit quietly under the baseboards and 'just work'!

P.S. I'll post the code when I get chance.