Way back when I started playing with the idea of using the dashboard tachometer as a voltmeter, I was aware I had one stumbling block …. I didn’t have a decent workbench power supply to calibrate the software/voltmeter against. In the end just using a battery and resistors the ball-park calibration wasn’t too bad, reading within a needles width of the correct voltage from 13 – 14v but it drifted terribly above and below this range.
Then in summer along came a gift from ABSL via Andy (Beasthonda) …. A very nice Thurlby 30V-2A dual power supply, which unfortunately had to languish in Oxford as it was too heavy to transport back by Capo! But patience is rewarded and it finally sits on the workbench, performing brilliantly and its first job has just been to calibrate the dashboard voltmeter once and for all. In the end it required a little code revision to get it just so, but it was worth it – now the voltmeter is accurate to a needles width over the full range of 9 – 16V. Happy Days! One more job to tick off the must-finish list. 😀
I really can’t say how much I appreciate Andy for thinking of me and ABSL for letting this power supply go to a complete stranger, I look forward to putting it to good use and hope that some of the tinkering on the workbench can make its way into other Caponords.