Step 1: Components Required
• Arduino pro mini (5V 16MHz)
• Bluetooth HC-05
• 10k potentiometer
• 10k resistor
• Aluminium foil
• Jumper wires
• 9V battery
• Battery connector
• Arduino uno or USB to TTL converter
• Android phone with bluetooth terminal app
• Digital multimeter
• Sweat band
• A pair of socks
Step 2: Making the Sensor
For this take two cardboard pieces of 4cm*2cm.Take two pieces of aluminium foil each of 6cm*2cm.One side of the cardboard should be covered with the foil and the other side to about half the length of the cardboard.Place the aluminium foil in this way over the cardboard and cover all the four sides in such a way that a small portion of the aluminium foil on one side of the cardboard is bare.Make another piece similar to this.
NOTE: Make sure that there is no gap between the foil and the cardboard. The only place there should be a gap is in between the bare aluminium foils of the cardboards when sandwedged together.
To one of the piece add a 10k ohm resistor so that it is in contact with the foil that is on the side of the cardboard that is not fully covered by the foil.Tape it in such a way that resistor does not moves.
To the other piece add two jumper wires on the similar side of the cardboard.Tape it in such a way that the wires don't move. I just used 1 wire and then had a tough time adding another.Make sure you use two wires before using tape.
Keep the surfaces of the cardboards with the bare aluminium foil surface facing each other and tape the entire arrangement.
NOTE:Do not tape it tightly.There should not be any contact between the foils when the arrangement is unpressed.
Finally check the arrangement using a multimeter.When pressed the resistance should decrease.
Step 3: The Circuit
Step 4: Android and Bluetooth Terminal
Step 5: The Code
• 'c' for calories burned
• 's' for speed
• 'd' for distance travelled
There is no need for the software serial library as we use the same Tx and Rx pins that communicate with the computer.
There are two ways to program the pro mini:
1. Using an arduino after removing the main IC
2. Using USB to TTL converter
Whichever method you use try it on the serial monitor of the computer before using the app.
In any case you feel all other data other than the step count to be wrong, there are plenty of online calculators that give various results based on step count.In this case you might be in need of the start and end time too. Print the variable t to check the time elapsed since the beginning of the execution of the code.
Step 6: Placing the Pedometer
Step 7: Testing and Usage
There you have your pedometer!