# Buzzing Mindfulness Bracelet
## Overview
https://www.youtube.com/watch?v=DJfGhETxWlw
Info:
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](https://learn.adafruit.com/adafruit-gemma-m0/circuitpython-digital-in-out?view=all) or [Classic Introducing GEMMA guide](https://learn.adafruit.com/introducing-gemma/introduction)
- [Adafruit Guide To Excellent Soldering](../../../adafruit-guide-excellent-soldering)
- [Battery Powering your Wearable Electronics](https://www.youtube.com/watch?v=U_Q3djsktQs)
For this project, you will need:
- [Gemma M0](https://www.adafruit.com/product/3501)[ or ](http://www.adafruit.com/products/1138 "Link: http://www.adafruit.com/products/1138")[Gemma v2](http://www.adafruit.com/products/1222 "Link: http://www.adafruit.com/products/1222") or [Gemma v1 (discontinued)](https://www.adafruit.com/product/2470)
- [vibrating mini disc motor](http://www.adafruit.com/product/1201)
- [1N4001 diode](http://www.adafruit.com/product/755)
- [PN2222 NPN transistor](http://www.adafruit.com/product/756)
- ~200-1K ohm resistor
- [100mAh lipoly battery](https://www.adafruit.com/product/1570)
- [heat shrink tubing](http://www.adafruit.com/product/344)
- [soldering iron and accessories](../../../../adafruit-guide-excellent-soldering)
- scraps of leather or bike inner tube
- scissors
- snaps and snap setting tool or velcro tape
- utility knife
- ruler
- pen or marker
# Buzzing Mindfulness Bracelet
## Circuit Diagram
Info:
A see-through bracelet would show off the circuit above:
- ~220-1K ohm resistor to GEMMA pin 1
- NPN transistor base (center pin on PN2222) to resistor
- NPN transistor emitter to GEMMA ground
- NPN transistor collector to motor black wire AND diode anode
- GEMMA Vin to motor red wire AND diode cathode (gray stripe)
- Battery plugs into tan JST port
It's difficult to fit the circuit inside the bracelet if you build it first. We'll be building it as we go, interlocked with pieces of the bracelet for the most compact fit.
# Buzzing Mindfulness Bracelet
## Bracelet
The bracelet is created from folded figure-8 shapes cut from leather or rubber. You can easily draw it yourself, or download this image and print it out ~1 inch wide (or trace the screen!):
Draw or glue the template to a piece of thick paper, illustration board, or piece of cardboard. Cut out the figure-8 shape using a sharp utility knife or craft blade.
On the wrong side of your material, trace the template many times and carefully cut out a small pile of pieces using sharp scissors.
To create the bracelet closure, cut out two special pieces with elongated tabs as shown:
Use a snap setting tool to attach the snap parts, or use velcro tape instead.
Sandwich the two pieces wrong sides together, and place a figure-8 through the center hole. Fold the figure-8 flat so it creates a new sandwich for inserting the next piece. Repeat to build up a few links.
GEMMA fits snugly between the layers, which expose the power switch but hide the USB connector and JST battery connector. Slide GEMMA in from the side, with digital pin 1 facing towards the working end of the chain.
Poke a small hole in the center of the next link and insert one leg of the resistor (doesn’t matter which), then also through GEMMA’s pin 1. Twist the lead so it makes good mechanical contact with the solder pad.
Next up is the transistor. Splay the leads away from each other, and use pliers to carefully bend them into place. Pictured above, the flat side of the transistor faces the same way as the flat side of GEMMA. Solder the base and emitter pins, being careful not to singe the material of the bracelet (although black leather can be very forgiving in this regard).
To prepare the motor/diode assembly, set up your diode in a third hand tool and tin the leads close to the diode itself. Hold the delicate motor wires up to the leads and remelt the solder to affix the motor.
Use heat shrink tubing to insulate the leads and help protect the tiny stranded wires connected to the motor.
Solder the motor/diode assembly to the transistor’s remaining pin (collector) and GEMMA Vin. The diode leads travel around the next link in the chain, concealing and protecting the circuit.
# Buzzing Mindfulness Bracelet
## Arduino Code
Info:
Load up the following code on Arduino GEMMA using the Arduino IDE. It should buzz the motor once per minute. If it's working, then adjust the interval variable to your desired number of seconds and reload the code.
https://github.com/adafruit/Adafruit_Learning_System_Guides/blob/main/Buzzing_Mindfulness_Bracelet/Buzzing_Mindfulness_Bracelet.ino
# Buzzing Mindfulness Bracelet
## CircuitPython Code
**GEMMA M0** boards can run **CircuitPython** — a different approach to programming compared to Arduino sketches. In fact, **CircuitPython comes factory pre-loaded on GEMMA M0**. If you’ve overwritten it with an Arduino sketch, or just want to learn the basics of setting up and using CircuitPython, this is explained in the [**Adafruit GEMMA M0 guide**](https://learn.adafruit.com/adafruit-gemma-m0/circuitpython-setup-1).
Info:
Below is CircuitPython code that works similarly (though not exactly the same) as the Arduino sketch shown on a prior page. To use this, plug the GEMMA M0 into USB…it should show up on your computer as a small **flash drive** …then edit the file “ **code.py** ” with your text editor of choice. Select and copy the code below and paste it into that file, **entirely replacing its contents** (don’t mix it in with lingering bits of old code). When you save the file, the code should **start running almost immediately** (if not, see notes at the bottom of this page).
**If GEMMA M0 doesn’t show up as a drive, follow the GEMMA M0 guide link above to prepare the board for CircuitPython.**
https://github.com/adafruit/Adafruit_Learning_System_Guides/blob/main/Buzzing_Mindfulness_Bracelet/code.py
# Buzzing Mindfulness Bracelet
## Wear it!
Add enough links after your circuit for your bracelet to fit your wrist. Peel off the paper backing from the motor and stick it in between layers of material.
Put some black tape or heat shrink tubing around your battery and plug it in. Wind the wire through the bracelet and tuck the battery between the layers of material. Loop the closure tab through the last link and wear it!
https://www.youtube.com/watch?v=U_Q3djsktQs
Your bracelet is not waterproof! You can take steps to [ruggedize your circuit](https://www.youtube.com/watch?v=kolq3eSu4ug) to make it more splash resistant, if that's your thing.
You can customize your bracelet's vibration by changing up the Arduino code. Maybe try using PWM to give the vibration more nuance or create different buzz patterns for different spans of time passed-- how would you make this project your own?
## Featured Products
### Adafruit GEMMA M0 - Miniature wearable electronic platform
[Adafruit GEMMA M0 - Miniature wearable electronic platform](https://www.adafruit.com/product/3501)
The **Adafruit Gemma M0** is a super small microcontroller board, with just enough built-in to create many simple projects. It may look small and cute: round, about the size of a quarter, with friendly alligator-clip sew pads. But do not be fooled! The Gemma M0 is incredibly...
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### Adafruit GEMMA v2 - Miniature wearable electronic platform
[Adafruit GEMMA v2 - Miniature wearable electronic platform](https://www.adafruit.com/product/1222)
**Deprecation Warning: The Gemma bit-bang USB technique it uses doesn't work as well as it did in 2014, many modern computers won't work well. So while we still carry the Gemma so that people can maintain some older projects, we no longer recommend it.**
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### Arduino GEMMA - Miniature wearable electronic platform
[Arduino GEMMA - Miniature wearable electronic platform](https://www.adafruit.com/product/2470)
What do you get when you combine an Adafruit classic with geniuses at Arduino? The Arduino GEMMA! It's a tiny wearable platform board with a lot of might in a 1" diameter package. Powered by a Attiny85 and programmable with an Arduino IDE over USB, you'll be able to...
No Longer Stocked
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### Vibrating Mini Motor Disc
[Vibrating Mini Motor Disc](https://www.adafruit.com/product/1201)
\*BZZZZZZZZZZ\* Feel that? That's your little buzzing motor, and for any haptic feedback project you'll want to pick up a few of them. These vibe motors are tiny discs, completely sealed up so they're easy to use and embed.
Two wires are used to control/power the vibe....
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[Related Guides to the Product](https://learn.adafruit.com/products/1201/guides)
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[1N4001 Diode - 10 pack](https://www.adafruit.com/product/755)
This here is a 10 pack of the classic 1N4001 power blocking diode. These are good for reverse polarity protection (put it between your DC power jack and circuitry to avoid a negative-voltage that would zap your delicate electronics), kickback protection (place across your solenoids, relays...
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### NPN Bipolar Transistors (PN2222) - 10 pack
[NPN Bipolar Transistors (PN2222) - 10 pack](https://www.adafruit.com/product/756)
Transistors are powerful little electronic switches, and we really like these NPN transistors whenever we need to control medium-power electronics such as small motors, solenoids, or IR LEDs. We find them so handy, they come in a pack of 10!
Each transistor is a general-purpose...
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### Heat Shrink Pack
[Heat Shrink Pack](https://www.adafruit.com/product/344)
Heat shrink is the duct tape of electronics, it keeps your stuff all safe and kept together. Especially when wiring and soldering, use heat shrink to add mechanical strength to cables. We use this stuff all the time and having a zip-lock bag of all the possible sizes is super...
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[Lithium Ion Polymer Battery - 3.7v 100mAh](https://www.adafruit.com/product/1570)
Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery has a capacity of ~100mAh for a total of about 0.4 Wh. If you need a larger battery,
In Stock
[Buy Now](https://www.adafruit.com/product/1570)
[Related Guides to the Product](https://learn.adafruit.com/products/1570/guides)
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