The odometer (though in kilometers) had a feature that forced it to stop advancing when it hit 99,999.9 KM. After disassembling the speedometer it only took a little push to move the counter past 99,999 back to zero. Well today it worked just perfectly. There was still 40 year old grease on the gears but I added some fresh just for good luck. I guess this starts the official counter of electric miles (or kilometers for those who can't do fractions).
Also, with about 5 lines of code, a 2.2K resistor and a 2N2222 transistor, it was trivial to connect the dashboard Arduino to the Smith Temperature Gauge. Using the
- Pin 9 PWM to drive the base of transistor through the resistor
- connecting the emitter to ground
- the collector the gauge's input (the original temp sensor input from the non-existent engine)
... the system worked. The other connector on the gauge was connected to +12V, once it was discovered the voltage stabilizer was not working well. The spade was lose which caused intermittent behavior.
Here is a shot of the odometer and temp gauge in full operation. The gauge is currently set to show 70C as "N" (mid-scale) so that should provide a quick indication for the driver if the motor is heating up.
A voltage gauge is on order to replace the oil pressure gauge on the right side of the speedo. This will monitor the 12V system to make sure it is operating properly.
