Friday, 11 June 2010


Using something like this you can move model locomotives around under software control.

If you had a series of optical detectors or perhaps good old fashioned reed switches, you could transmit ones and zeroes by positioning the locomotives. If you had long platforms and short trains you could have perhaps four (2 bits) detectors per platform. If you had locomotives with some kind of detectable unique marking on them and you had the ability to switch trains between platforms (now that would be fun to watch), you could send different values by arranging them. If you had four platforms and three trains there would be 24 combinations. I can't think of a setup that would be a nice power of two, but wouldn't it be more fun to transmit a non-integer number of bits with each arrangement? And think of the fun you'd have working out an algorithm to shuffle the locomotives around, towers-of-hanoi style.

Sunday, 6 June 2010

An itch you just can't scratch.

If you attach a webcam to the carriage of some electromechanical device (I have a Commodore MPS-1230 dot matrix printer) you could wind the carriage backwards and forwards and point the webcam at one of two images (say, a cross and a circle) which you could pick out with some simple image recognition. You'd just have alternately print lines of, say, 20 or 60 characters and let the carriage return at the end of every line using, you know, a carriage return.

The best thing about the MPS-1230 (and I admit, its benefits are few and far between) is it can be operated over the DIN serial port on the back of a Commodore C64. Which has a range of exciting input options, like a set of TTL GPIOs.

Bonus points if it's a Wifi webcam.

IP over Fatness

Something I've seen a little of lately, if you had some Bluetooth or internet-enabled weighing scales, you could exert a force on the scales to transmit a reading. You'd have to check and see what kind of accuracy you can get and how much force you can generate with Meccano. You could place one of two weights on the scales for 0/1, or if you could generate the force mechanically (and accurately enough) you might be able to get 4 or 5 bits per reading. A screw and a spring might work, as long as you can lift it clear of the scales so they can calibrate on power-up.

I like Bluetooth for this application because it adds lots of lovely layers to the stack diagram.

IP over Sonic sonics

I'm sure you could do something with a Sega Megadrive (I happen to have one of those, well an Amstrad Mega-PC, but close enough). If you could find a game where A and B made different noises, you could run the line-out cable to a PC and do a real-time FFT to work out which button was pressed.

Or, you could capture the video output and detect whether Sonic was facing left or right (0 or 1) with 'duck' as a clock pulse.