Small coin cell batteries are inexpensive and useful, with one big problem, how do you connect to them? You can purchase holders for cylindrical that are complete with wires to make it easy to connect to your project, but not so for coin cells. Here is a very simple solution for using coin cell batteries to power small projects. The holder will work with almost any coin or button cell, even tiny hearing aid batteries. Since the cost is so low, this method is ideal for Maker Camps and other kid activities.
Step 1: Materials Needed
Materials needed will be a spring clothespin, some hook-up wire (24ga is a good size), some 3/8" heat shrink tubing (the type with the internal adhesive is best), and some conductive foil tape.
Step 2: Tools Needed
Tools you need are a Dremel tool with a chuck and a small drill bit (use #60 bit for 24 ga wire), a heat source to shrink the tubing, and a soldering iron with solder. A small drill-press would also be an excellent way to drill the required hole.
Step 3: Prepare the Clothespin
Using the small drill bit, drill a hole through both sides of the clothespin. Try to center the hole in the flat area where the two sides touch.
Step 4: Preparing the Wire
Cut two pieces of wire to a length suitable for your purpose. Red and Black with are a good choice for Plus and Minus polarity. Strip back about 3/4" of insulation off each wire. Twist the strands together and tine using the soldering iron and solder.
Step 5: Insert the Wires in the Newly Drilled Holes
Insert each wire through the hole in each side of the clothespin. Pull the wire snug and fold it forward. If the hole is the proper size, the insulation should not be able to enter the hole. This makes a nice tight assembly.
Step 6: Apply the Conductive Foil Tape
Using copper tape, or a similar material, cut small pieces and apply to the inside face of each side. The foil tape is not required, but it does give a better contact surface. It also helps secure the wire.
Step 7: Securing the Wire
Cut two pieces of heat shrink tubing about 3/8" long. The best tubing is the shrink-seal tubing that has the internal hot-melt glue. If you don't have shrink-seal tubing, secure the wire with a dab of hot-melt glue. Slide a piece of tubing up the wire and around the clothespin. Shrink the tubing with a heat source such as a hot-air gun.
Clip the battery holder on the battery. Place the plus side of the battery on the red-wire side and the minus side of the battery on the black-wire side. Note that the holder will hold almost any size coin or button cell, even the tiny hearing aid batteries. In the photo, a CR2032 battery was used. This is a 3 volt Lithium battery. If 6 volts are required, simply stack two Lithium batteries.