I'm now going to explain how to create a Bike GPS step by step.

Step one :

Creation of the summing amplifier.

To create it we need :

• 2 resistors of 10K Ohm
• 1 resistor of 1K Ohm
• 1 resistor of 20K Ohm
• 1 resistor of 22K Ohm
• 1 operational amplifier (LM358 for this project)

• The Bluetooth Headset (Explorer 10 - PLANTRONICS)

Electronic diagram of the summing amplifier :

In this electronic diagram, the part connected to the positive input of the amplifier allows the addition of 2.5V. That is to say, to pass the voltage between 0.8V and -0.8V to 1.7V and 3.2V. The part connected to the positive input of the amplifier allows the amplification of the signal otherwise the arduino card can't receive the frequency sent by the smartphone.

Step two :

Connect all the components to the summing amplifier.

We need :

• The neopixel ring (NeoPixel Ring - 24 x 5050 RGB LED)
• The Arduino Micro

Be carefull of the pins you use on your program and welded to the arduino card !!

Electronic Diagram of all the components connected :

Step three :

Creation of the source code. I've created a Github folder with the source code and the necessary libraries.

Here is the link to see this : Source code on Github

This program is recovered the frequencies send by the smartphone, it then made an average every 5 frequencies to have a better accuracy. Finally, depending on the frequency average, the leds light up in the desired direction.

Step four :

Creation of the frequencies :

To create the frequencies I've used the software Audacity.

In the toolbar menu click on "Generate/song", a window opens : in waveform select sinusoid; in frequency choose the one you want; in amplitude choose 1; for the time I think the best is 2 seconds. Then click on "OK".

After, in the toolbar menu click on "File/Export audio" save this file as the name of the file in OsmAnd with the extension .ogg and replace the file in the folder voices in your smartphone. (for example if you choose to create a 440Hz file to turn right, save it as "right.ogg" then put this file in the folder voices to replace the "right.ogg" which said "turn right").

Our frequencies are available, in relation with our source code, in Github. You just have to replace the frequencies in the folder of the OsmAnd application with the frequencies available in Github or with your own frequencies.

Step five :

Creation of the packaging :

To create the packaging I have used a 3D printer and CharlyRobot.

With the 3D printer I have created the fixation, the box and the lid and I have made with CharlyRobot a protection in Plexiglas but it is possible to create all the packaging with a 3D printer.

You can find this file on Github.