Follow the steps below to solder the hardware in the project. If you're new to soldering be sure to read the guide to excellent soldering.
Note the IR receiver is optional. If you choose not to use the IR receiver then ignore the instructions that deal with assembling and connecting it to the Gemma. Without the IR receiver you will only be able to program one animation to constantly run instead of being able to control animations with the remote control.
Cut your NeoPixel strip down to the size you'd like to use for your torch. For a 16oz mason jar a strip of 6 NeoPixels (from the 30 pixels per meter strip) works great, and for a 32oz mason jar 10 NeoPixels are best. Make sure to only cut the NeoPixel strip on the line with exposed solder pads between pixels.
Start by soldering wires that are about 3-4" long to the NeoPixel strip and IR receiver. It's easiest to 'tin' each wire and pin by heating them with the iron and touching with solder to leave a thin layer of solder on the part. Then hold the tinned parts together and heat them with the iron to flow the solder again and fuse the parts.
Make sure to solder to the end of the NeoPixel strip with the arrow pointing towards the pixels (the signal line can only flow in one direction on a NeoPixel strip).
Add heatshrink to the connections on the IR receiver to prevent them from touching and shorting out.
Next solder the NeoPixel strip and IR receiver to the Gemma as shown in the Circuit Diagram section.
Once the parts are soldered together gently bend the IR receiver so it's facing behind the Gemma, and the NeoPixel strip so it forms a U shape as shown below.
Continue on to learn how to install the Arduino sketch that controls the hardware.