Using Coin Cell Batteries in Solder-less Breadboards.
I just recently purchased some flickering LED candles at the dollar store ( 2 for $1 ) to remove the flickering LEDs, the subject of a possible future blog post. These LED candles came with a CR2032 3V coin cell battery. Not bad, the LED and a battery for 50 cents. So, now I’ve got a few of these CR2032 batteries and I started wondering how I might connect them up to a project or experiment on a solder-less bread board. Now, I could go on line and order battery holders for these coin cells but that would take time (and money, they cost more than the battery), and I’d have to solder wires to the battery holders as well. Not exactly part of the plan if you are trying to go solder-less.
A picture of the CR2032 battery is shown below. The thickness of the cell is 0.12" or 3.2 mm which is slightly bigger than the 0.1” spacing of a male to male square pin header, also shown below, like the ones supplied with the Analog Discovery module as gender changers for the female fly wire connectors.
CR2032 3V coin cell
0.1” male to male header pins
Break off a pair of these pins. The plastic spacer will keep them 0.1” apart. Slide the two pins a little to one side, making one end longer and the other shorter, but not too short to still fit properly in the breadboard. Using a small pair of long nose pliers, a slight offset can be bent into one of the now longer pins to increase the gap between the pins so they just snugly slide over the battery. The bottom of the battery case wraps up the side so it is best to put the bent pin on the bottom side of the battery to better avoid inadvertently shorting it out. A strip of masking tape about twice as long as the diameter of the cell will hold the pins in place nicely. The battery will now very nicely plug into two adjacent rows on the breadboard ( be careful not to insert it into one row ( turned 90 degrees ) or it will short out.
The two pins sticking out can be more easily shorted, so you will need to be careful when storing them when not in use. A female header with the pins removed, or at least cut off short can serve as an insulating shield or guard.
If you prefer a female connector this same trick could be done using one of these long pin stackable female headers shown here.
Female stackable header
These don’t break apart like their male counterparts so to get just two pins will take a bit more mechanical work.
One would suppose that one could use this trick on other coin cells that are thinner or thicker by bending pin headers spaced in increments of 0.1”, 2.54mm. You might also find headers with 2mm spacing.
As always I welcome comments and suggestions from the user community out there.