Make an Electronic Device in the Street (IR Pen)

Sometimes you don't have enough materials and space to make any instructables so you keep reading them ...
I wanted to make some very simple instructables so anybody can do it anywhere. It won't be the most impressive instructable but may be the most basic in electronics.

This first hack can be done on the street without soldering iron or else.
Ok, I've done mine on the kitchen table and a bulky soldering iron is visible but you can definitely make it in your jungle, could be green or grey jungle. 

My motivation is a mix: my kids can try (9 and 4 years old) + I'm not equipped with good electronics anymore + I live in apartment + I prefer to invent something new than going to stores + it saves the planet and my purse too.

I needed IR pens for Wiimote whiteboard and wanted to used a dirty cheap "Wii sensor bar" ($3, in fact there are no sensors but IR leds, sensors are in the Wii remotes), it's the less expensive way I found to get 6 IR leds already soldered on a board.
I also wanted to use AA batteries that you can replace in your device.

The minimum you need for any this kind of cheap electronic device is:
- aluminum foil
- duct tape or any tape
- scissors
- an electronic device to hack, here a Wii bar
- screwdrivers to open your device
- wire cutters to cut your electronic board

The trick here is simply to use aluminum foil and tape to make: battery case + switch + holder for the electronic part.

Step 1:

Cut a piece of duct tape and roll it with adhesive outside the battery.
Usually duct tape width is the size of an AA battery. If it's not the case, simply cut your tape.

Keep it a little bit loose so you can change battery later.
This tape roll will be the holder of everything try to keep it sticky.

Step 2:

Cut aluminum bands.
While battery is within the tape roll, stick one aluminum band on the positive side and add a piece of tape to keep this band forever in place.

Step 3:

Use another band to make the contact and switch:
Start near the positive band laying on the side of the battery and finish on the negative cap. You must have some space between the foil and the negative pole of your battery.
Also keep some of the band to help remove the "switch" to change the battery.

Step 4:

Open the device, here the Wii sensor bar and get the board and cables.
Cut the board near the piece you want to use, here IR leds and add tape on it.

Step 5:

Positioning this tape+device in place can be tricky.
Start in the middle and finish with the tape.

If you use a led like me and it doesn't work, simply remove the negative band and make another one on the other side of the positive one.

If you have a multimeter, you can test your contacts before testing your device.

Step 6:

Since the aluminum band is loose on the negative side, you got a switch when you "click", push the band on the battery.

Now you have a street made electronic device.