The JST battery connector is located on the side of the Feather M4 Express. To fit the boards inside the handle, you will need to reroute the connection so the battery connects from the end of the Feather M4 Express.
Measure and cut a JST Extension cable so it's 54mm long. Tin and solder the wires to the back of the JST connector. Make sure to verify the power and ground are connected in the correct pins with a multimeter. Check that the wires have a solid connection and curve the wire towards the prototype area on the Feather M4.
Solder the PropMaker Wing
Now we can place the PropMaker Feather wing over the Feather M4 Express.
We used the Assembled Prop-Maker FeatherWing to make it easy to solder to the Feather M4 Express.
Align the headers so the PropMaker sits flush on top of the JST battery connector. We can use a Panavise to securely hold the boards while we solder each header pin.
Now to dry fit the boards in the handle. Here, measure wires for the USB jack, Reset Button, Slide switch, LED strips and the optional mode switch button.
Place the USB connector and jack over the end of the handle to visualize how the rest button will sit on top of the USB jack.
Make sure the board is flush against end of the handle to get accurate measurements of the wires.
We love silicone ribbon cables. They don't melt when soldering and help to keep wires neat and organized.
Measure 20mm of ribbon cable. Reference the circuit diagram for the USB connects.
First, apply a bit of solder to each pin on each USB connector and the carefully solder each wire.
Apply solder to the Reset and Ground pins on the PropMaker.
We utilized the strain relief hole to help route the Reset wires before soldering to the button.
Solder the wire to each of the two pins on the button. We'll insulate the connects with hot glue later to allow it to fit in the handle.
Next solder the On and Off slide switch to the G and EN pins on the PropMaker. Tin the through holes first and then reheat while press the wires into each through hole.
We'll need to route the wire between the center of the two boards to the opposite side of the board as shown. Pass the wires through and then solder the slide switch.
Once all of the wires are soldered, go ahead a double check that the lengths of all wires are correct and have enough slack to reach.
Mount the Slide Switch
Maneuver the wires for the On /Off slide switch so they are flush against the handle walls. The slide switch press fits into the slot on the handle.
Gently pull the two metal tabs on the slide switch metal housing to increase the slot tolerance. Hot glue in place to help secure it.
Now to preparing the NeoPixel strips. Identify the start and end of the strip by looking at the direction of the small arrows printed on the strip.
Cut off the large connector and remove a small bit of silicone so you can solder to the pads on the strip. Repeat with the second NeoPixel Strip.
Both strips will connect via a Y splitter. We used a JST PH 3-Pin to Male Header Cable to build our splitter.
Cut six silicone wires 20mm long and then use tweezers to hold them together while soldering to the jumper ends of the JST PH 3-Pin Header Cables.
Check that the connections are solid and then slip on heat shrink to insulate the connections.
Next is to test that the LED strips turn on.
Hot Glue Components
After verifying that all wires and components power up without any loose connections, you can start to mount the board and wires.
Apply hot glue to the corners of the board and then use Air Dust to quickly dry the hot glue. You can turn the Air Duster upside down and carefully spray quick bursts over each glue spot.
Some condensation will appear but quickly fades away as the temperature stabilizes.
Lay the strips so they have a small amount of spacing between the edge and center of the blade walls. This will help to diffuse the blade. Apply hot glue and Air Duster to hold the strips in place. Add glue to every 80mm or so to straighten out the strip.
Mount USB jack
Apply a small amount of hot glue to the end of the handle where the USB jack sits, but not at the tip end. Press the USB jack over the glue.
Check that it's properly aligned and then quickly spray Air Duster to hold it in place. Add another small drop of hot glue over the USB pins to insulate the connections. Allow the hot glue to drip down and adhere to the handle before using the Air Duster.
Once the hot glue dries on the USB jack, place the Reset button over the USB jack plastic housing and then apply a small amount of hot glue on the sides of the Reset button. Don't apply hot glue to the top. This will make it too thick for both halves to join.
Insulate the pins of the Rest button with a small amount of hot glue.
The optional Mode switch button can sit above the Reset button. You can add a small drop of hot glue to the sides and the pins to insulate the connections.
Once the speaker is mounted in the handle, it will sound muffled, so a couple of holes should be put in the handle. We heated a poking tool (usually included with 3D Printers) and made a pattern of holes over the area around the speaker.
Add holes to both sides of the handle.
Poking each hole will leave raised edges around the holes, but they easily clean up with a diagonal Flush Cutter tool.
Now you can start to attach both halves of the sword. The rope detail on the handle will actually help to hold both halves together.
Cut a piece of green paracord 320.5mm long and then tightly criss cross the rope down the length of the handle.
Tie the ends and then apply a small amount of super glue to the area were the rope criss crosses to hold the shape of the paracord.
Hot Glue Blade
With the handle tightly attached, you can move on to adhering both halves of the blades together.
Start at the base of the blade. Apply a generous amount of hot glue as shown in the diagram. Lay the blade on a flat surface and apply pressure as you add hot glue to each section. Use Air Duster to quickly dry the hot glue.
Allow the hot glue that spreads out of the sides of the blade to dry before using a hobby knife or flush cutters to trim them off.
Take your fully assembled sword on your next quest! Don't forget to make a second smaller one for those younger Adventurers! Just remember to fully charge the battery before going on long missions!