Arduino Nano
I2C OLED 0.96" Screen
3d Printed Bracket
1N4148 Diode
0.25w 120ohm Resistor
Estimated Price: $20-40 depending on whether or not you're using a clone Arduino
Install the libraries provided in the files, install them to your arduino libary folder, usually C:\Users%username%\Documents\Arduino\libraries. I used Arduino 1.6.6, but newer versions should work. Will not work with Arduino versions prior to 1.4.3. In the libraries folder, you should have a "SSD1306Ascii-master" folder with files inside after unzipping.
Arduino must be run at least once to generate the "Arduino" folder inside of "Documents." https://www.arduino.cc/en/Main/OldSoftwareReleases
4.7k ohm pull-up resistors, from the +5v to the SDA/SCL lines, may also be used to prevent occasional screen freezing.
Sometimes, especially on hard braking, the Arduino freezes. I am unsure of how to fix this, and the reset button does not fix it. I recommend installing a NC button to reset the Arduino on the +5V line, or simply stopping the scooter and restarting it.
An updated 3D printed case that fits the nano is available here, on thingiverse: https://www.thingiverse.com/thing:3453576
Print in PETG or ABS for heat resistance. PLA goes too soft in the summer. Glues such as E6000 are required for installation.