Quantity   Component name
1 × Hat Any kind of hat works, beanie, baseball cap, etc.
8 × Vibrator motor Small vibrator motors for haptic feedback.
1 × Arduino Nano Arduino Nano or equivalent small microcontroller.
1 × HMC5883L Breakout board (GY-573) Any 3-axis digital magnetometer will work, I used an HMC5883L. An MPU-9150 may be even better.
1 × DC-DC Step-up transformer Need to take the battery voltage up to 9-12V.
1 × Lithium Ion battery + holder Any flat battery will do, a cell phone battery along with a charger works best.
1 × Wire I used 28 gauge stranded teflon-coated wire
1 × Wire-to-wire and wire-to-board connectors I used Dupont-style connectors, male and female, mostly wire-to-wire connections
1 × Needle and thread