Let’s open this blog with a personal project I’m working on in my limited spare time:
A CUSTOM LIGHTSABER!
Yeah I know, I’m super original but I can’t help it. I’ve wanted one since I’m 5 so let’s get to it and make Past Jeff proud. I’ve actually started this project a few weeks ago but I haven’t done much and I kept going backward as I’m having a hard time finding the right electronics for the job.
Specs of the project
Right now, as I’m still a newbie in electronics, I just want it to be able to light up to a specific color (that can be changed thanks to an auxiliary button). When I’ll have a good setup and better understanding, I’ll see if I’ll try to add sounds and light effects based on movements but since it’s a bit out of league in terms of coding, I wanna start simple (never used audio amps and accelerometers/gyroscopes)
First thing I need to settle is the electronics I’m gonna use since it’s gonna directly impact the design (overall diameter for the battery pack):
- 2 meters of Neopixels strips (WS2812 chips) (144/m or 60/m depending on the brightness needed)
- A small microcontroller to control the neopixels
- A couple of buttons to turn the saber on and off and selecting the color
- A battery pack to power up everything
The core component is the Neopixels strip but they can drain quite a lot of current. About 20mA per pixel.
If I use a 800mm blade with 144led/m pixels, that makes about 110 pixels x 2 strips = 220 pixels total. 220 pixels * 20mA=4400mA=4.4 Amp
Same blade length but with 60led/m, 50 pixels x 2 = 100 pixels. 100 pixels*20mA= 2000mA=2Amp
This greatly limits the choices of battery so I initially went with a 4*AAA battery holder that would have house 4 NiMH for a total of 4.8V that could deliver roughly 2000mAh. I thought about using a phone powerbank (2000maH with 5V regulated) but the max output is only 1A.
The problem with this build is that the battery pack that I planned to use (4*AAA in square, not like the schematics) is too big (31*31mm). Typical lightsaber hilts are about 28mm in diameter and 290mm in lenght. After a few online searches, I noticed that a battery type was quite popular for lightsaber makers: the 18650 Li-Ion battery. It’s has between 2000 and 3000mAh and operate at 3.7V. It’s small and packs a lot of mAh, perfect right?!
Only problem is that the Arduino Nano operates between 6-20V… But luckily, there are other boards on the market, like the Adafruit Trinket 3V. It’s super small, got enough processing power for what I plan to do and will work perfectly with the Li-Ion battery. Only drawback is that I’m pretty sure I won’t be able to add an accelerometer/gyro + amp for sounds based on movement with this build.
With the electronics sorted out, I decided to tackle the hilt. As usual, I decided to go with 3D printing so I opened up my 3d modeling software and started modeling the key parts and designed the casing around.
As you can see, I went with an original design. I searched online and took inspiration of designs bits I liked. The idea is to have a “core” that can be used a template for future build. Here’s the prototype and almost final look (may be subject to changes)
So, I also need something to house those neopixels right? I decided to go with a D25mm plexiglass tube. Two strips, placed back to back, will be wrapped in foam and inserted in the sanded tube to have a good diffusion.
I’m still experimenting to see if 144/m strips are absolutely needed or if 60/m strips will be enough with clever diffusion.
And that’s it for this project so far! As said earlier, It’s a personal project I get to work only on week ends.
What’s next? I need to continue testing the blade to get the best diffusion and I need to order some Trinkets 3V as I only have Nano’s and 5V trinkets at home. When I’ll get that, I’ll be able to start soldering the electronics.
Stay tuned for more!
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