Prepare NeoPixel Strip
NeoPixel strips are sold by the meter. The medium density strips have 60 LEDs per meter. We recommend ordering a 2 meter strip so its long enough to fit the entire length of the sword. The strip starts at the end of the handle and up from the base of the blade to the tip and then loops back down towards the handle.
The entire length of the strips will need to be 151mm (59in) for a total of 93 NeoPixels.
We can also solder multiple strips together to fit the whole length of the sword.
Removing silicone ends
The included wires on the NeoPixel strips are too big to fit inside the sword, so we'll need to unsolder them and replace them with flexible silicone wires.
We can use scissors or flush cutters to remove the ends of the sheathing by inserting the cutters tips between the end and the rest of the sheathing.
Solder to strips together
With the silicone ends removed we can now join multiple strips together if needed. We can add both strips to third helping hands to make soldering easier.
Make sure the arrow labels on the strips are pointing in the same direction so the data flows in a continuous direction.
Here's how to connect multiple strips together. Tin the pads on both of the strips and carefully apply solder. Then, slide the solder onto each pad.
Now we can move on to measuring and tinning the wires for the NeoPixel strips.
The NeoPixel strip wires will need to be 141mm long to reach the Trinket when its mounted to the handle, over the battery and walls around the handle.
After cutting the wires to length, tin both end of the wires. Apply a small amount of solder to the pads on the NeoPixel strips and apply heat to connect the wires to the pads.
A slide switch will make it easy to power the circuit on and off. Prepare the switch by removing one of the pins on the left or right side of the switch.
Don't remove the middle pin!
Measure two wires so they're 170mm in length. These need to reach the slide switch and the Lipo Backpack.
Now we can prep the Trinket and Lipo Backpack by securing them to a pair of third helping hand. This will make it easier to solder.
We need to enable the on/off function in order to use the switch to power the Trinket. You'll need to cut the trace near the 5V pin. You can use a hobby knife to cut the trace as shown in the picture.
Tin and solder Trinket and Backpack
Now we can tin the 5V, G and BAT pins on the Lipo Backpack. Connect the 5V on the Lipo Backpack to USB pin on the Trinket.
The NeoPixel 5V wire and Lipo Backpack wires for BAT will both need to be soldered to the BAT pin on the Trinket. The 30 gauge silicone wires are thin enough to easily insert both wires to the BAT pin on the Trinket. With them both in place, apply solder to the pin.
Ground, Data and Slide switch
Next up we'll need to share the ground pin on the Trinket with the NeoPixel strip and the Lipo Backpack . Insert both of the ground wires inside ground pin on the Trinket and apply solder.
Connect the data wire from the NeoPixel to GPIO pin #4 on the Trinket. We can tin the pin and then apply heat while inserting the wire.
Slide switch wires
Finally, we can connect the slide switch wires to the two pins on the Lipo Backpack. Polarity doesn't matter, so you can connect the wires into any of the two pins.
Mounting the circuit
Now we can mount all of the boards to the standoffs on the handle. The Trinket needs M2 x 4mm machine screws. Orientate the Trinket so the USB port is facing the cutout in handle. Make sure to trim any excess material around the port opening to easily fit a USB cable.
The Lipo Backpack needs a single M2.5 x 5mm machine screw. Position the board with the JST connector facing the wall.
Now we can plug in the battery wire into the Lipo Backpack. Route the battery wire around the wall cut away and seat the battery in between the two walls.
Route the wires for the slide switch around the wall cut away and use the flat side of a pair of tweezers to push the switch into the opening on the upper part of the handle. Make sure to remove any excess material around the opening.
Adding the NeoPixel strip
Add four pieces of Nitto tape to the middle part of the upper blade, like shown in the picture.
Next up we'll add the NeoPixel strip with the LEDs facing outward. The sides of the strips adhere well to the Nitto tape pieces. The NeoPixel strip should follow the contour of the blade.
With the components now mounted to the parts, we can move on to joining the two halves together. The two are held together with twenty M2 x 12mm screws. That's a lot!
And that’s it! Now we have our very own guardian sword. The thing we like most about this design is that it’s really durable, so you can swing it around and not worry about it falling apart. Using the screws to secure all the parts together was really great idea and it’s easy to take part if we ever need to.