Make Your Own Bluetooth Gps Navigator Bracelet





This project consist of a bluetooth bracelet connected to the user's smartphone, who indicate when to turn or do a maneuver.

The main aventages of this project instead of a traditionnal gps or a smartphone are:

  • It drains less battery on the smartphone.
  • It doesn't required earbuds or headset (who can be dangerous on bicycle or motorcycle).
  • It doesn't required special mounts.
  • It vibrate when you need to do something.

It's made of several leds and a cellphone vibrator.

The bracelet indicate the road to take with some combinaisons of blinking light and vibrations. For exemple, when the user should take the left road, the left LED will blink and the motor will vibrate at the same time.

When the user should take the 3rd exit of the roundabout, all LEDS will blink 3 times and the motor will vibrate 3 times also.

It recalculate the route if the user take the wrong road and calculate the best route for the selected locomotion.

It's based on the google direction API, it will be replaced with a opensource alternative in the future (mapquest, skobbler or even Mapzen.

It's not perfect,I don't have a incredible skill in programming, but I want share my work instead of let it rotting on my HDD.

This project is made with some opensources technology and the help of tutorials on the internet (which include instructables ;) ), so I let it opensource for everyone.

Have fun ! :D

Step 1: Parts

This is the list of components you will need for this project.

  • 5 LED (3mm)
  • 1 3.7v 20c 240mah battery
  • 1 HC-06 blutooth transmitter
  • 1 ATTINY 84
  • 1 Arduino Uno
  • 1 Capacitors (10µF/25V)
  • Some jumpers
  • 1 opaque plastic piece
  • 1 Lithium Battery Charge Controller
  • 1 cellphone vibrating motor
  • A band
  • A case (optionnal)
  • 1 slide switch

The case can be downloaded here :
(Solidwork and stl file)

Step 2: Program You ATTINY84

There is a nice tutorial to install the ATTINY84 library here :

Then select the ATTINY84 and burn the 1Mhz bootloader.

Wire like on the picture:

After that, send this .ino file into the ATTINY.

Step 3: Breadboard Time !

Set everything up like on the picture.

You can add resistor for each LED if you want to.

There is also the frizting file here:

Step 4: Test Everything

Power up the circuit and connect the bluetooth module to your smartphone.

Type 1234 for the pin number and install the following app :
Bluetooth MAC Adress

Get the MAC adress of the bluetooth module

Then test the circuit with this app :

The source code of the cordova project is in the rar archive

Step 5: Generate Your Google Map Key

First of all, go on your Google API Console

Then create a project and go to credentials.

Generate a new api key.

Step 6: Install the Application

There is the apk and rar which contain the source code

Step 7: Change Preferences

Go in the preference menu (press this icon on the top right corner)

Then put your key and the bluetooth mac adress in those fields

Step 8: Conclusion

Thank you reading this instructable :)
This project have taken a lot of time, so I would like that everyone respect what I made.

I know I made a lot of mistakes, so don't hesitate to remade your own version, comment what's wrong in the comment section or you can go on the github.

I would like to thanks some people for them incredible great work :D.

-The Apache Cordova Fundation

-Don Coleman (who made the bluetooth serial plugin for Cordova)

-The arduino foundation


I will make a github for this project and I think I will maintain the project.

The bracelet can be use for other things.

A pebble smartwatch version will come out.
Respect the opensource community, if you republish it, I would like to be credited.

Thank you for respect those principle.

Github link : here

My youtube channel : here

My email address : nicolas[dot]mahieu[dot]isf[at]



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    19 Discussions


    3 months ago

    Hi Its a good project. But when I am using it with my mobile phone it's giving me errors. Its not showing directions on the map and if i click the start button, its giving me erros
    Error: Uncaught Type Error: Cannot read properly 'get' of undefined in"my key"&sensor=false&libraries=geometry at line 26

    please help me with this issues asap

    3 replies

    Reply 3 months ago

    Hello, sorry for the long delay
    I've got some questions :
    - Did you used the apk or did you compile the source ?
    - Did you put your own google map key in the preferences ?
    - Which android version did you have ?

    Thanks in advance and your interest in the project;

    Have a good day,


    Reply 2 months ago

    I have tested it with the APK which you have provided but with the API key of my google account which had the plan of pay as you go.
    I have the latest version of Android - 8.1.0
    I am using HC-06 Bluetooth for communication

    Please reply asap to resolve the issue

    Chitlange Sahas

    1 year ago

    Deserves a lot of credits. Thank you so much for sharing, :) :)


    2 years ago

    Awesome project ! i will try to make my own and post here if i encounter any problems .

    Btw, in the video , doing the turning demos your bracelet was blinking like it was on steroids :D


    2 years ago

    why a straight led did not work in test with android_debug.apk?

    4 replies

    Reply 2 years ago

    I'm going to remake it from everything I posted on this instructable.
    If I make some changes, I'll tell you here.
    If everything, work, I'll do the same.
    Have a good night,


    Reply 2 years ago

    I remade everything from the start with the .apk on the instructable and everything work like expected.

    If you found the solution of your problem, please write it the comment section.

    I'm going to make the instructable more precise


    Reply 2 years ago

    If you can send a video and a clear picture of the wiring, I'll get a eye on it.


    Reply 2 years ago

    thanks for fast reply. the LED problem is solved now, but i found another problem. please see my message in your instructables inbox.

    thanks for help :-)


    Reply 2 years ago

    And also, have you yourself created this application? What is Google API console? And what is API key?

    Thanks if you can help me build this?


    Reply 2 years ago

    Sorry for the long answering time.

    This weekend, I will modificate the instructable to answer all questions.

    Thanks you for all your questions, you participate to the instructable and that's great :)


    Reply 2 years ago

    And also, how should i download the app on my phone? I tried clicking on the apk link on my phone, but nothing is getting downloaded.


    Reply 2 years ago

    Merci monsieur ça fait plaisir ^^

    Je ne connaissais pas les ingénieurs sans frontières