Slide Switch
We'll need to connect a slide switch to the Adafruit Feather by wiring it to the enable and ground pins. This will allow us to power the 3V regulator on and off. I used 30AWG silicone cover stranded wire because it's strong and flexible. The length of the wires can be about the same length of the Adafruit Feather.
Prep Switch
We'll only need two of the three terminals on the slide switch. Using flush diagonal cutters, remove of the terminals (either the far left or right, but not the middle!). Then, shorten the two remaining terminals by cutting them in half. Now you can tin the two remaining terminals with a bit of solder – This will help make soldering them to the wires easier.
Strip Wires
Using wire strippers, you want to remove a bit of insulation from the tip of the two wires.
Tin Wires
Next we can tin the tips of each wire by applying a bit of solder. Tinning the wires will help prevent the strands from fraying. A third helping hand can help keep the wires secured and held in place while applying the solder.
Connect Switch to Feather
Now we can connect the switch to the Feather by soldering the two wires to the Enable and Ground pins, respectively (doesn't matter which wire as long as one goes to enable and other to ground). I recommend using a Panavise Jr. to keep the Feather secured while soldering.
Test Switch
We can test out the switch by plugging in the battery to the Feather. Sliding the switch back and forth will power the circuit on and off. The on-board status LED and NeoPixel LED will light up indicating that it's receiving power from the battery. If everything works, you can disconnect the battery and set it aside for now.
