Arduino Nano ATMega328p Arduino Nano Every ATMega4809 (Register emulation not required)
2.42 Inch SS1309 128x64 Monocrhome OLED
5v Beeper
5v Speed sensor (#DSSA from www.carbuildersolutions.com)
OLED_MOSI 9
OLED_CLK 10
OLED_DC 11
OLED_CS 12
OLED_RESET 13
Beeper 2 (and to GND)
Speed sesor 4 (and 5v, GND)
ODO - Press return and then enter new odometer reading
PPM - Press return and enter pulses per half mile (use CAL mode in preference)
CAL - Enter calibration mode (see below)
RUN - Exit calibration mode
In calibration mode it starts counting pulses immediately. Calibration should be done over a measured half a mile. Press enter when starting the half mile, and again at the end. The number of pulses will be displayed on the screen. To write this to EEPROM and return to normal mode type 'RUN'. If the data is not suitable (missed marker etc) then just repeat the measurement.