We like etextiles a lot - they make soft materials projects way more interesting and you can learn about electronic circuits in the process. The lilypad and sewable holders you can buy are really good but we are in New Zealand and thanks to being miles from anywhere and the rubbish exchange rate at the moment they can be expensive when we want to use a large number to run classes.

Our Fab Lab has a 3D printer, and there was some copper strips out back so we made our own, they are not as nice as the bought ones but they work pretty well and you can make any colour you want.

Step 1: Materials and Tools

Materials

3D printed battery holder - we printed ours on A Makerbot Replicator 2 with PLA at standard settings. You can download the STL file below.

5mm wide Copper strip (the kind used for leadlight windows)

Tools

Wire cutters

Needle nose pliers

Tweezers

Craft knife

coin_cell_battery_holder.stl
Download View in 3D

Step 2: Copper the Negative Terminal

1. Feed the 3cm piece of copper through the slot as indicated in the photo, note the hole in the base is closer to what will be the shorter positive terminal.

2. Wrap a few millimetres around the hole, bending underneath.

3. Wrap other end around the terminal with the hole.

4. Flip it over to see if ends are securely wrapped around the base.

Step 3: Copper the Positive Terminal

1. Bend one end of the 2cm piece of copper into a V as in the photo - bend 3mm off the end, then 3mm in the other direction.

2. Feed it into the slot on the positive terminal (where the hole is closer to the edge) from the inside where the battery sits. "The upside down V" end should sit vertically.

3. Wrap the last few millimetres around the hole, bending underneath.

4. Flip it over to see if ends are securely wrapped around the base.

Step 4: Pierce the Sewable Holes

1. Using the sharp tweezers of a big needle, pierce a hole through the copper wrapping the terminal. Make sure it goes through the plastic hole and the copper on the other side.

2. Repeat with the other terminal. Flip to see if there are holes on the base too.

Step 5: Test the Battery Holder

1. Place a CR2032 coin cell battery into the holder.

2. Connect 2 alligator clips to the positive and negative terminals, and attach to the corresponding legs of an LED. It should light up.

3. The most common reason for this circuit not lighting is wrong polarity - try flipping the LED legs round. If it still doesn't light, then have a look at the copper tape "V" fold inside the holder where the battery sits. If it is flat, it will only connect with the negative side of the battery and short circuit. The V must be vertical - the tension from it helps keep the battery in place too.