Dual Blade, 4 buttons, long distance with a neopixel in between wiring

Okay so I’m trying to figure out wiring. This is a funky saber because it has 2 chassis, 2 blades, and a neopixel blade connecting the 2.

On one side of the hilt is a blade connector, 2 pushbuttons and a battery. On the other side of the hilt is 2 buttons, a speaker, another blade connector the board and a kill switch.

connecting the 2 is a short led strip. Any wires I run need to be very careful setup with that so they aren’t visible since the run through the diffuser tube.

I’m trying to figure out where I can wire directly to the battery to avoid running back and forth.

The kill switch is on the side opposite of the battery which is irritating. At a minimum I am running battery+ across the center to the kill switch, and then back.

Do I need to run the negative across too, or can I just wire to the battery?

Bad diagram -

blade,btn,btn,battery<–>neopixelstrip<–>btn,btn,killswitch,speaker,board,blade

It seems to me that you’re going to need two LED strips in the center tube, so as long as your wires are sandwitched between the two strips, they won’t be visible. That might be a little fiddly to do, but you should be able to fit enough wires I think.

Let’s take a look at how many wires you would need through the middle with no optimizations:

  1. BATT+
  2. BATT-
  3. Button1
  4. Button2
  5. Blade-
  6. Blade data

Note, we do NOT need a GND for the buttons, we can just use BATT-, which is the same as GND.
We also do not need a Blade+ since that will just connect to BATT+.

Three of these wires (1), (2) and (5) would need to carry a fair amount of power.

Now let’s see what we can do to reduce it…

First up: “blade data”, if we use a subblade, then we can use the data that comes out of one of the pixel strips to connect to “blade data”, which eliminates (6).

If the pixel strips have good solid copper for + and -, then we might be able to do a similar optimization for “blade-”. The power needed for the blade would be drawn from the end of the two middle pixel strips, which would eliminate (5).

And if we can push enough power thourgh the strips one way, there is no reason we can’t do it the other way. Batt+ is going to have to connect to the (+) side of the two middle strips anyways, so we can connect the + side of the strips to BATT+ on the board on the other side. (through the kill switch.) This eliminates (1).

We have three wires left: BATT- & the two button wires. If we want to get really fancy we could wire up some special codo and resistors to get rid of one of the button wires, but I probably wouldn’t bother. Instead what I would do is to get some 10-lead ribbon cable, use 2 wires for buttons and the other 8 for BATT-. 10 leads of ribbon cable should be only slightly wider than a pixel strip (depending on the strip) so it should sandwhich nicely between the two strips.

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Oh, I should point out that as long as your blades use LED* to control the power, you don’t need to cut LED+ to the blades, it’s enough to cut LED+ to the board.

Cool, is it this one? If so, I also got one of these in the todo pile.

Yup, that’s the model.

The pixel strips i have are already stuck together. No idea what the innards like in regards to the wiring, but they’re a well trimmed dual sided set of neopixel led’s from Saberbay.

Is running power through these strips sufficient or should I just run 22awg lines? There seems to be plenty of space to run 2 22awg lines, and the data lines are tiiiny.

For the subblade, I would just bridge the 2 led strips, and treat both sides as a single line? Then run the outputs from the mid-strip to the blade?

And unrelated, I am finding this build so much more fun than previous ones. LGT saber chassis was so small that it was a constant fight to get everything to fit. In this case there is so much room for activities and wiring choices.

Only complaint is snaking cables is tough.

I’ll try to pass al this through the mid blade save for batt- and the 2 buttons. Worst case I burn something up and learn a valuable lesson, and then can run wires through the center of the new strip i get.

I have no idea. It depends on the internal resistance of those strips. Trimming the strips means less copper, so who knows? If you can measure the resistance, then we can calculate it, otherwise you have to just try it and see if it causes blade dimming.

For + and -, you can bridge at both sides. (Just make sure you do it right so you don’t bridge + to -) For data, you should bridge the inputs, but not the outputs. If you want to use subblade and connect to the next blade, just connect one of the outputs to the input of the next blade.

The reason for this is that the two signals might be slightly out of sync when they come out of the blade, and connecting them together means you get a mix of two signals, which might not work.

Re data outputs - Got it.

I think i need to order a new set of intermediate strips because they came stuck together and seem backwards. Like i if I bridge them I’d bridge - to + and + to - which seems bad. Everything else seems to be going smoothly.

This has been super helpful. I’ll circle back once i get the new led strips.

That’s generally going to be the case for every set of strips unless you zig-zag them. (Meaning that the data goes up one strip and down the other.) However, if you do that, then the data “out” ends up back where you started, so it’s more difficult to use it as with subblade.

So I am questioning my ability to do this well with both the complexities of the config, and my questionable soldering.

My new approach is going to be to replace the badly soldered led strips in the center with a clean set. Still setup the same way with the bridging mentioned above, but I’ll just run 3 blades.

Because I can assemble the internal strip (and I ordered enough strips that I can mess it up like 8 times), I’ll just run wires across in the center. Slightly more wiring, but it’s cleaner for me to debug the electronics.

On the positive side, the righthand blade/speakers/buttons/kill switches all work awesome.