Quantity   Component name
1 × Arduino Pro Micro 5V usb hid needs a atmega32u4 board though
1 × OLED IIC/I2C Display (3-5V) http://www.ebay.de/itm/400736083040
1 × A3144 Hall Effect Sensor (4.5V) http://www.ebay.de/itm/130702520481
1 × 5V USB power supply