Build yourself a buzzing bracelet for subtle haptic feedback as time passes! It's great for reminding yourself to get up and walk away from your desk for a few minutes each hour, or just as a way to have a new awareness of how the perception of passing time varies based on what you're doing.

You'll whip up a vibrating motor circuit using a transistor, resistor, and diode, and use GEMMA to control the frequency of vibration in between low-power microcontroller naps. The circuit lives inside a linked leather/rubber bracelet, but you could build it into whatever you please. This project involves some precision soldering, but is otherwise quite easy!

Before you begin, make sure you've read the following prerequisite guides:

• Gemma M0 guide or Classic Introducing GEMMA guide 
• Adafruit Guide To Excellent Soldering
• Battery Powering your Wearable Electronics

For this project, you will need:

• Gemma M0 or Gemma v2 or Gemma v1 (discontinued)
• vibrating mini disc motor
• 1N4001 diode
• PN2222 NPN transistor
• ~200-1K ohm resistor
• 100mAh lipoly battery
• heat shrink tubing
• soldering iron and accessories
• scraps of leather or bike inner tube
• scissors
• snaps and snap setting tool or velcro tape
• utility knife
• ruler
• pen or marker