On/Off Switch

 To start this project, we'll work on making the on/off switch first. Gather up the JST extension cable, JST right-angle female connector and the slide switch. We'll use this parts to build a on/off switch. This will allow us to easily cut the power from the circuit. Be sure to check out our DIY On/Off JST Slide Adapter guide to get a full step-by-step tutorial. This guide summarizes it since it's only a portion of the build.

Measure & Cut JST Extension Cable

Arrange the JST extension cable, slide switch and female JST connector on your work surface. We'll need to cut the JST extension cable so the wires are a certain length. Grab hold of the end with the male JST connector and measure the cable so it's 62mm in length. Then, cut the red and black wires. We'll only need the end with the male JST connector, so we can store the other end for another project. Next, separate the red and black wires from the JST cable by pulling them apart. Then, cut the red wire in half so we have a separate connection. Now we can layout our components like shown the photo.  We'll need to connect the two red wires to the slide switch, and the black and red wires to the female JST connector.

Prep Wires for Switch

We'll need to strip and tin the tips of each wire in order to more easily attach them to the other components. Use wire strippers to remove a bit of insulation from each wire. Then, tin the exposed strands of wire by applying a small amount of solder to them. This will also prevent the strands of wire from fraying. You'll need to do this for each wire (thats a total of four tips). I suggest using helping third hands to assist you while soldering. The helping third hands can keep wires sturdy while you tin the wires.

Attach Wires to JST Connector

Now that we have our wires prepped, we can work on connecting wires to the female JST right-angle connector. Start by secureing the female JST connector to the helping third hands. Then, tin the two electrodes by applying a small bit of solder. Before you solder the wires to the slide switch, I suggest using some pieces of heat shrink tubing to insulate the exposed electrodes. Now we can solder the red wire (the one we cut from the male JST cable) to the positive electrode on the JST connector. Note: The positive electrode has a visible notch on the top surface of the female JST connector. Then, solder the black (negative/ground) wire from the male JST cable to the negative (ground) electrode on the female JST connector. 

Prep Slide Switch

We'll need to prep the slide switch so that we can attach wires to the terminals. Start by removing one of the terminals from the switch using wire cutters – Either the far left or right, but NOT the middle! Then, trim the remaining two terminals short. Now we can tin them by applying a small amount of solder to them. This will make it easier to attach wires to the electrodes.

Connect Wires to Slide Switch

With our slide switch prepped, we can now connect wires to the electrodes on the slide switch. We'll need to solder the positive connections from the male and female JST connectors to the two electrodes on the slide switch – These red wires are the positive(red) wires from the male & female JST connectors. Connect them to the slide switch by soldering the tips of the wires to the electrodes.

Slide Switch JST Adapter

And now we have a slide switch JST adapter that we can use to power on/off our circuit. We'll connect our battery to the female JST connector. The male JST connector from the slide switch will connect to the female JST connector on-board the Adafruit GEMMA. For now, we can set it a side and work on connecting the NeoPixel Jewel to the Adafruit GEMMA.

Prep Wires for NeoPixel Jewel

Now we can work on connecting the NeoPixel Jewel to the Adafruit GEMMA. We'll need three pieces of wire to connect these two components together. First, we'll need to measure out how long the three wires need to be – We found 24mm long wires to be suffice for this project. Use wire cutters to cut three pieces of wire, 24mm in length. We used 25AWG silicone coated wires because they're great for flexible connections. You can use different colored wires to help tell the connections apart, but it's not a requirement. Then, use wire strippers to remove a bit of insulation from the tips of each wire. After that, we can tin them by add a small amount of solder to the tips of each wire.

Connect NeoPixel Jewel to GEMMA

Insert Wires Into GPIO 

Secure the two components to third helping hands with the back of the PCB facing up and bring the two arms close to each other like shown in the photo. This will make it easy to solder wires to each board. Insert the tips of each wire into the corresponding pins. This will make it easier to solder the wire in place.

• GND from NeoPixel to GND on GEMMA
• Data In from NeoPixel to D1 on GEMMA
• 5V from NeoPixel to VOUT on GEMMA

Solder Wires to Gemma and Jewel 

Apply a small amount of solder to each pad on the Gemma. Try not to apply too much solder the large pads on the Gemma. Tin the pads on the NeoPixel Jewel and then solder the wires for power, data and ground. And now we have the NeoPixel Jewel connected to the Adafruit GEMMA, yay!

Circuit Sandwich

Fold the NeoPixel Jewel over the Gemma so the flat sides of the boards are back to back. The LEDs should be facing outward like in the picture. If the wires are too long or stick out, we will need to shorten the wires to make it compacted inside the enclosure. Now we should be able to lightly compress the two boards together. Make sure the wires are small enough to stay hidden between the two boards.

Install Slide Switch

Next, we'll work on fitting the slide switch into the 3D printed enclosure. Grab the two parts and start working the slide switch into the enclosure. The body of the slide switch will be housed into three walls located inside the enclosure. Press the body down in between the walls until its flush with the surface. The actuator from the slide will protrode from the side of the enclosure.

Install Battery

Now we can connect the battery to the slide switch. Connect the male JST connector from the battery to the female JST connector thats attached to the slide switch. Next, carefully place the battery into the enclosure. You'll need to fit the cable from the battery into the enclosure, so we need to arrange the wiring so it's neatly packaged into the case. We found it best if you coil the wiring and tuck it inbetween the walls of the enclosure so it stays in place. The male JST connector from the slide switch should be accessible. Next, we'll connect the Adafruit GEMMA to the slide switch.

Connect Slide to Gemma

Now we can connect the male JST connector attached to the switch to the female JST connector on-board the Adaruit GEMMA by plugging the male JST connector to the female JST connector. Make sure the switch on-board the Adafruit GEMMA is set to the ON position. Next, we'll work on install the NeoPixel Jewel and GEMMA assembly into the 3D printed enclosure.

Install NeoPixel and GEMMA

Now we'll need to insert the NeoPixel and GEMMA into the 3D printed case. Lay the assembly on top of the battery with the NeoPixel LEDs facing up. You'll need keep all of the wiring contained within the enclosure. You may need to press the component together and hold them in place to install the cover. Next, we'll screw the top cover onto the enclosure.

Twist top

Grab the 3D printed top piece and place it over the enclosure. The cover and enclosure feature a custom thread that coils around edges of the parts. With the cover ontop of the case, slowly press them together and turn the cover clockwise until the threading meet and start screwing together. Keep turning until the two pieces are fully secured together. And thats it! Now we have our self-contained assembly, ready to wear, place or install onto our project. Sweeet!

Usage

Attaching to Human Skin

We used3M Nextcare Transpore Flexible Clear Tape (a medical grade tape) to attach the enclosure to the palm of our hands. Tegaderm Tape is similar and specifically designed to adhere to human skin.

If you plan to attach the enclosure to another surface, you'll need to pick the right adhesive for the job – This depends on the materials. Cyanoacrylates (super glue) or E6000 work well for most applications. Just make sure you still have access to the power switch when securing the enclosure to another surface.