Piggyaxe Binary Timery tweaked for improved accuracy

December 8th, 2013

Been busy at work with an ‘Inspection’ which as far as I can tel went well, then I got on with something educational…..

The binary timer software was checked against a clock and 8 thousandths of a second were added to the time-trimming loop, so my rough guess about processing time was not far out! I have not investigated the effects of temperature on the internal RC oscillator, but I’m sure either the Picaxe or Microchip datasheets for the 14M2 will tell you. Its not an atomic clock timer so it does not really matter – as-is its fit for purpose. I have also wired up some amazing little 3-axis G sensor boards, selectable 1.5 G or 6 G, plus a free-fall output. (eBay for about £1.50 delivered!) and written a few lines to control three servos. They all waggle as expected, i.e. up-down, left-right and forwards-backwards. At the moment its just a novelty box to interact with (pupils love it) but I had an application idea when reading an article about building a satellite tracking beam aerial. I have not checked to see if its linear yet but it would make a useful 180 degree potentiometer if you had something that needed that….like the horizon to horizon azimuth (via the pole star!)  controller. Although suitable geared motors exist in abundance, coupling a potentiometer to provide positional feedback is always a bit of a nightmare. For a heading controller I seem to remember that Rapid Electronics (and quite probably by now eBay) sell ‘electronic compass’ modules that could deal with that problem too. A lot easier than gearing a 300 degree potentiometer to represent 360 degrees.