Battery holders of course hold batteries and are VERY useful in electronic projects especially those that require batteries. This is the simplest battery holder I could come up with. The best thing is that it is cheap and it uses household items that everybody should have. If you want to make a holder for a larger battery then adjust the dimensions accordingly.

Keep in mind that this is my first instructable, so please be gentle. And please hit the little + thingie up there.

Step 1: Materials and Tools

For this holder you need tape of some kind. I used electrical tape because its awesome and it is maybe a better insulator than cellophane but if you don't have electrical tape then use cellophane, its better than duct tape in this case. You also need cardboard preferably from a cereal box because it is sturdy and thin. You also need aluminum foil because it is conductive and easily shaped.

You need a pen to mark the measured points on your cardboard and aluminum foil. A ruler is needed to accurately make the holders otherwise you're going to have one wonky battery holder. You need an exacto knife or scissors. An exacto is more exact ;) but scissors work wonders cutting the tape straight. The golf tee is for scoring the aluminum it isn't neccesary.

Step 2: Measure

Measure the approximate dimensions of your battery.

In order to get the right dimensions you must measure the width as accurate as you can. This dimension is the most important because the battery must fit.

The length desn't have to be exact but get as close as you can. Remember not to measure the nub on the end of the positive terminal.

I measured a AAA and it was 1 cm wide and 4.3 cm long without the nub.

Step 3: Mark and Cut Your Cardboard

First make a vertical line on your cardboard. (assuming you laid it with the long side facing you)

Then somewhere along your line make 4 ticks each 1cm apart.

Make a 4.3cm long line on every tick perpendicular to the first line.

Finnaly make a 3cm long line on the other end of your 4 lines.

Then cut the outside lines that you drew on your cardboard. It doesn't matter what order you do it in.

You should now see 2 lines on your cardboard.

See the pictures for more details.

Step 4: Measure and Cut Aluminum Foil

Make a line 4cm long.
Make 5 marks on the first line spaced 1cm apart.
Then draw lines 3.5cm long perpendicular to the first line on the marks you made before.
Then close off your box with a 4cm line on the end.

Cut the outside lines on your aluminun foil box.
Then cut the inside line on your box.
You should now have 2 pieces of aluminum foil both with a line down the middle and each piece should be 3.5cm long and 2cm wide.

Fold each piece in half along the line.
0.5cm from one end on each piecemake a cut 0.7cm long.
Do not cut from the part where you folded it over.

See the pictures for clarification or more detials.

Step 5: Score and Fold Your Cardboard

Get your piece of cardboard that you cut out previously.
Use your exacto knife and score along the 2 lines on your cardboard.
Fold the sides up in the way that is the easiest.

OPTIONAL

Flip your piece of cardboard over so that you no longer see the side that you drew on before.
Make 2 marks close to one end and another 2 marks close to the other end. Each mark must be 1cm from the side closest to it.
Then draw 2 lines from one end to the other following the marks opposite each other.
Score along these lines.

I made mine this way because it helps to give the finished product a better look.

See pictures for better explination on how to do optional step.

Step 6: Aluminum Foil Meet Cardboard

Take a piece of foil and 1cm from the end make a mark. It should be close to the end that doesn't have the little piece folded up.
Do the same to the other piece.

Take your cardboard and line up a mark on your foil with the edge of one of your side walls.
fold it over the gap at the end of your cardboard and do the same at the other end.

Take a piece of tape longer than your aluminum foil and tape the foil to the end of your cardboard.
Repeat on the other end.
Take your exacto knife or scissors and cut down in the corners of the tape that overhangs at the bottom.
Then fold down the excess tape to cover the bottom.

Step 7: And You're Done ;-)

You are now done.
Test it out. Just pop in a battery and connect your wires to the tabs. It doesn't matter which way you put the battery in because there isn't a spring that connects the negative terminal.
The battery gets held in there pretty good too. Mostly by the pressure created by the foil contacts and the sides of the holder.

This will be a very versitile in your electronic projects.

Enjoy!!