## Introduction: WAC (WALK AND CHARGE GADGET) - Reusing Old CD Drive

### Hello everyone, I am Chris

a student of class XI and this is my first instructable. This project was made by me when I was 11 y/o (I was too shy to post my projects just to show them to everyone)

*Sorry for any mistakes. English is not my native language

In this instructable, we are going to make a gadget/device which could charge your phone even when you are on the go ( walking/ jogging ). Have you ever experienced that your phone is always fully charged when you are at home, however when you go out somewhere, you see only 12% of the charge is left? So I came up with this idea, named it WALK and CHARGE GADGET(WAC). Now worry no more because, this gadget will make sure that your phone/device is always fully charged not only when you’re at home, but also when you are out / going to school or any place. Right, this gadget does exactly what it sounds like. It could charge your device while you are walking or running but in a very unconventional way. And you don’t have to worry if you don’t have any 3D printer because instead of using a 3D printed model, we will be re-using some old materials, which are quite easy to get( and if you have 3D printer then that’s great... actually I don’t have that, you guys are great )... just a reminder- I made this project when I was 11 y/o, so it might/should require some revision... ( I would be very happy to know from you guys).

let's burn some calories.

Functioning in brief~
Our knees tend to bend while walking/running in a fixed pattern or let's say in a periodic motion. So this gadget will be attached to the knee portion. How does it work? The periodic motion will make the CD drive tray move in to and fro motion, which will rotate the Pre-installed DC motor( working as dynamo here ) in both clockwise(1st half) and anti-clockwise direction (2nd half). Thus, the dynamo here will generate some uneven flow of current. The alternate flow of current will be rectified by a set of diodes (full-bridge rectifier). Then to make the current flow constant(to an extent), we'll be using some capacitors. An, at last, to make the output drop-down from 7v to 5 v we’ll be using a DC-DC buck converter

Further development~

I would like to make it more compact and sturdy by using a 3D printed model and also I would like to use an actual AC dynamo instead of a DC motor( which comes pre-installed with the CD drive ).

watch the video here

## Supplies

Materials required~

1. OLD CD DRIVE - snatch it from your dad’s PC. (just kidding.. don’t do that, if you don’t have any old PC, you could just buy only the CD drive tray from here

2. Velcros -1metre

3. Diodes-4

4. Capacitors-4700 mFd x 3

5. DC-DC buck converter (6-24 v to 5) here

6. Superglue/Tape

7. Wires

9. USB cable

10. Power bank (optional)

Tools required~

1. Soldering iron with soldering wire

2. Multimeter

3. Scissors

4. Measuring tape (optional)-for measurement

## Step 1: Preparing the CD Drive(part 1)

(in case if you have bought the CD drive tray, then proceed to step 2)

If you have got the CD drive~
i) Extract the CD drive from the CPU

ii) Open the case carefully

iii) Remove the deck(the metallic frame where the spindle motor is connected) from the cd drive

ii) Remove the solder joints between the DC motor and the main circuit board

iii) remove the main circuit board from the frame with the stepper motor ( the one which is connected to a long screw-like rod ).

## Step 2: Preparing the CD Drive(part 2)

i) Remove the lock mechanism from the body by cutting/tearing/boiling or by your mystic psychic powers, whichever way you prefer.

ii) But make sure that the gears are all safe and also the tray can be pulled out completely from the main body.

iii) If you are unable to pull the tray completely from the body, then cut off the parts which are blocking the path of it.

*if you are wondering whats that white pencil-like object is - it keeps the tray on track.

## Step 3: Designing the Circuit~

i) Solder the capacitors in parallel, make sure that they are all connected in the same way(fig 3)(considering that all the capacitors you are using are polarized capacitors)

ii) Solder the diodes in this way(first image). This is will work as a full bridge rectifier.

iii) Solder or connect the DC-DC buck converter to the circuit

iv) Solder, the terminals of the DC motor to the circuit.

v) You need to connect the USB cable to the buck converter

vi) Place the USB buck converter on a plane surface, and glue it to the cd drive.

it's a good time to check over all your connections and ensure everything is in the right spot and nothing is missing (last video).

*if you are wondering whats that other blue circuit/board in the video- that is also a dc-dc buck converter, but the red board is much efficient. Still, have doubts? check here. Since the output is greater than the 7v, so I don't recommend you use this buck converter(the blue one)

## Step 4: Preparing the Velcros

i) Measure the width/circumference of your thigh by the measuring tape, and cut a pair of velcros according to the measurement. E.g If ‘x cm’ is the measurement, then cut each side of the velcro of length x/2 + 10cm(fig 6), so that if the length of both sides is added, then the resulting length will be around x + 20cm.

ii) Now repeat the above step for the portion just below the knee. The final result may somewhat look like this

## Step 5: Preparing the Velcro(part 2)

i)Cut a piece of cardboard(first image)and paste it the cd drive(second image)

ii)Join the velcros to the CD drive using glue or tape.

ii)Use superglue if needed

## Step 6: Congratulation,

you have reached the final step. Now you are ready to test it for the first time. Wear it to one of your legs. Connect your phone to the USB cable and go out for a walk.

And don’t forget to give it a final touch(last image).

thank you.

Participated in the
Wearables Contest