Actually, I used the "Copy to Forum" tool in the interface, and then posted it here using the button... I take it I'm just supposed to post the code as it comes out of the interface right in the main text box?
The voltmeter is working. Had to use a stubborn second 10K pot in line with the first.
Onto the oil pressure gauge. Got that working, too. Used the second 10K pot again.
I seem to have run into an issue...
Circuit looks kind of like this:
5V source from pot and voltage divider circuit---in port on second pot with other resistors added to bring resistance down to 90 ohms max, pot input pin---ground via ground pin on pot. Output pin on pot is connected to the Nano.
Other than the intake temp sensor (tach and speedo/odometer are separate, obviously), I have ONE WIRE senders (and I don't think 2-wire senders are available). Meaning that the gauge signal wire (use electromagnetic gauges) goes to ground through the sender. There are 2 sets of resistance coils in the gauges, and they balance out according to how much voltage is being sent to ground via the sender.
I can't very well connect the analog input to the 5V line or the gauge would never read anything but low. If I were to switch to CAN communication with the MSII, I'd lose oil pressure reading (MSII has signals for intake temp, battery voltage and coolant temp).
Also, the MAX7221s should be here tomorrow. I've only been waiting since I ordered them from eBay on the 27th (same time as I ordered the starter kit which arrived almost 2 weeks ago now). Once I get those, I'll see what I can do with the MAX7221spi example provided in the library.