Need help picking hardware for a Lightsaber Crystal project

Projects General Guidance
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Hello everyone,

I'm pretty new to Arduino and could use some help getting started on a project I wanted to do. I just got back from DisneyWorld and picked up some Lightsaber Kyber Crystals from the Star Wars Galaxy's Edge area. I've been looking into 3D modeling to create a rock and crystal holder for my Kyber Crystals. What I was really hoping to try and do was make the crystal clusters transparent with an opening for an LED bulb underneath so that I can make the crystals glow. Here's kind of an example of a smaller version of a 3D printed crystal holder and what the Kyber Crystals look like:

kyber crystal holder

Here's an example of how I'd like it to look with the LED's lighting up the crystals, just I'd put a little slot for the Kyber Crystal to go:

3D printed kryptonite

The idea would be, it would be a bigger "rock" with 6 big openings for 6 different crystal "clusters." What I thought would be really cool to try and do would be use the RFID chip that's already inside the Kyber Crystals to determine what LED color shines. Similar to how the lightsabers that you use the crystals in have a reader in them to tell the lightsaber what color to be. (Red, Blue, Green, etc.) So, technically, if you have an RFID reader/programmer, you can reprogram any crystal to be any color. (i.e. you can turn that Red crystal into a Green crystal by giving it a new RFID tag number.)

It'd be awesome if I could attach a micro RFID reader inside the base of each crystal cluster slot that could read each specific Kyber Crystal when it's placed into it's holder. Then, depending on it's specific code, it would tell that LED what color to shine. Also, if there is no Kyber Crystal in the cluster, it would shut that LED off. That way I could just make all of the crystal clusters the same semi-transparent clear material, which would make printing them a heck of a lot easier/cheaper. As well as be able to use the same Arduino code for each of the 6 crystals clusters.

I'm not at the coding part of the project yet, what I was hoping for some help with is the hardware for it. I've been trying to look around for the parts I'd need, but I'm having some trouble.

I already have an Arduino UNO that I've been playing with and an On/Off switch, so that's not a big deal. I was just going to get a big rechargeable battery pack and add a slot in the back of the rock that I can plug a charging cord into.

The LED's are causing me a bit of a problem though. I'd need an LED setup that can change to a bunch of different colors for each individual crystal cluster, but all of the digital color changing LED's I can find are those big long strips. Does anybody know of something that might work better that I could put into 6 different slots and could provide the whole color spectrum? Or would I just have to get one of those color strips and cut it up? Is there a good LED people have used for small projects like this that would work better?

And then the only other problem I've been having is figuring out what kind of micro RFID reader would work best. Or if it would even work at all? Does this sound like something that could work? I'd need a small RFID reader I could hotglue underneath each crystal cluster. I don't really know anything about RFID readers. Does anybody have an idea of a good micro reader I could use? It'd have to be a reader that could read 125kHz since that's the frequency the Kyber Crystal RFID's are at.

Another thing I don't know enough about yet is how the RFID's work with Arduino and if I could even run 6 readers off 1 Arduino UNO? Would it be able to handle that many readers with changing colors and whatnot? Especially if all 6 LED's are on at the same time.

Anyways, I could really use some help, even just getting pointed in the right direction. After looking around the forums a bit I think I found some code that could work for the LED color changes. I just need to get all the parts together so I can test it out. Any help would be greatly appreciated! Thanks!

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You can daisy chain a bunch of these

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That's perfect!! Although, can you separate each individual LED to a specific RFID reader? I guess I could code each RFID reader with a specific number, and pair that number with a specific LED. Then depending on which RFID reads a number, it activates that paired LED. I think that could work.

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Google is your friend: https://www.amazon.com/ALITOVE-100pcs-WS2812B-Addressable-Arduino/dp/B01D1FFVOA/

I've use similar behind a large canvas painting with pinholes to make the stars "twinkle".

Apply as many of you need per crystal. Some soldering required.

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Awesome! Yea, those should work great! Now I just gotta find some kind of micro RFID reader. I've been searching for the past week for LEDs and readers and I haven't been able to find anything. It's tough because I'm really new, so I don't even know really what to be searching for. So all I can do is type in stuff like "individual LEDs for Arduino projects" and stuff like that. And all that finds me is the long strips.

I'm still having trouble with the RFID readers, but like the LEDs, I don't even really know what I'm looking for. Eventually I'll just have to pick something and try it out. See what happens. Haha! But that's ok too, I was just hoping to save some wasted time and money. I guess it's all part of the fun.

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You can really only have one RFID reader for the whole assembly. Can you give us a link to your proposed "micro RFID reader"?

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Well, that's part of my problem. I don't really have the experience to know what's out there. I was just kind of going off of what Disney used for their Lightsabers. They have some kind of RFID reader on one of their boards and a small coil at the base of the slot you put the crystal into that reads the chip and tells the LED what color to be.

Savis saber RFID
Savis saber RFID1366×768 72.3 KB

savis hilt with crystal
savis hilt with crystal810×427 48.7 KB

I was hoping I could kind of take that same setup/design and basically recreate it 6 times, 1 for each different color, and have 6 slots to place the crystals that illuminate whatever color the crystal was. I wasn't sure if an Arduino UNO could do 6 different readers at the same time though. Maybe using something like a couple of these:

or

But I have no idea. Would something like reading an RFID chip and changing the color of a RGB LED light be something a smaller Arduino board could handle? Something like an Arduino Digispark is only like $4 on Amazon. The back of the rock would probably be big enough where I could maybe just get like 6 of those and have each one power and control 1 RFID reader and LED light. Then just copy the same code over to each Arduino and hook them all up to a big rechargeable battery bank?

Does that sound like something that could work? It'd look like a mess inside, but if it worked, I think it'd be a pretty awesome display.

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I would say forget the RFID idea, it's completely overkill for this - you don't need to identify thousands or millions of different crystals and you don't need the high security features of RFID either. It won't work anyway, because each RFID reader will be able to read any and all nearby crystals, so it won't be possible to tell which crystal is in which position.

I think you need to find some other way for the slot to identify the crystal placed into it.

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I don't know if I'd consider it overkill. Maybe a little bit, sure. But, there's tons of projects on here where people are using RFID readers to turn on/off lights, lock/unlock doors, just fun small projects here and there, etc. Yea, I don't need the security functions and I won't be reading millions of cards, but I don't know what else I could do. The crystals already have an RFID chip in them, why not try and use it? Plus, creators on Etsy are already making custom crystals of all different kinds of colors with chips inside them too. So, I could program those chips to be whatever colors I wanted as well. Then, no matter what color crystal I get, all I have to do is program it once and place it into any of the slots and BAM! That'd be so awesome! Haha!

Yea, the reading range would definitely be an issue, but a lot of readers are listed as only having like 1cm-7cm's worth of distance anyways. I just need to make sure my rock mold would place each crystal about 5-6 inches away from each other. That's not a big deal. I wanted it to be a decently sized display to begin with.

The biggest problem I can foresee is kind of what I was talking about in my last post. I don't know enough about RFID readers to know how they work with Arduinos. Would I need to get multiple Arduinos? One for each reader? Or could I program one Arduino to identify and separate each reader individually so it could read multiple readers?

I'll spend some time looking at what other people did with projects requiring multiple RFID readers. Like, what would you do for using an RFID reader to open multiple doors? One reader for the front door and one for the back. Could you put both readers onto one Arduino? Or would you need separate Arduinos for each task?

Otherwise, I don't know how else to do the project. The only thing I could think of is maybe some kind of potentiometer in each slot where you would put the crystal and spin it to get the color you want? Or some kind of bluetooth card where I could control the color with my phone? I feel like, no matter which route I go with, it's going to be a little complicated, so why not try to figure out the coolest one? It might get complicated and expensive, but I guess that's part of the fun, right? Disney was able to get it to work, there's gotta be a way. :slightly_smiling_face:

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You don't need multiple readers, you only need one. I supposed each "crystal" is coded with a specific data that you read via the RFID reader, and based on that data, you change the color of a neopixel LED.

There are multiple versions of RFID so you have to make sure that the reader is compatible with the RFID chip in those crystal you buy off Etsy.

I've personally used this before and it can "talk" to an NFC enabled phone

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So, I'd only need 1 reader for each of the 6 slots? I figured I was going to need a reader/antenna for each spot since they would be holding a crystal in each slot and controlling an LED for those spots. Here's kind of a rough Paint drawing I did to show what I was hoping it'd look like:

Crystal Holder Concept 1
Crystal Holder Concept 11254×559 30.2 KB

I figured, I'd space each boulder out so each crystal slot would be at least 5" or 6" apart. I'd then wrap the RFID antenna around the base of each of the boulder openings on the underside of the mold. There'd be a small hole in the center bottom of each of those openings where I'd hot glue the LED. Then, you could pick which semi-transparent crystal cluster you wanted and slot it into the opening. When you place a Kyber Crystal into the holder, that antenna would read the chip and turn the LED on to a specific color.

After doing a little more research, it looks like the RFID chips inside all the Disney crystals and custom Etsy crystals are EM4305 chips that operate at a 125kHz frequency. So, I'd have to find a low frequency, short range, 125kHz reader that reads EM4305 chips. I feel like I'm at least getting somewhere. Haha.

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Please explain how a single reader can identify which crystal is in which slot.

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I was able to find this post from a couple of years ago where she hooked up 4 RFID readers to 1 Arduino UNO for an Escape Room puzzle. You would need to place the card tags on all the readers at the same time to open the door. She also says in her Youtube video that she only installed 4 in the video because she was in a hurry, but that she could install up to 6 readers on the 1 Arduino UNO board.

So, it looks like it's possible to attach 6 RFID readers onto 1 Arduino UNO board. I would just need to find the appropriate reader that can read those specific 125kHz EM4305 chips. Then figure out what kind of code I would need to recognize the assigned tag numbers and assign RGB color values to output that matching color.

Also, in the Youtube video, the RFID readers she was using were only a couple inches away from each other and didn't seem to have any problems with detecting only a single card. I think this could actually work. Wooo!

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Looks like you do need however many "crystal" you have for the readers based on the drawing. I was under the impression you are mimicking the lightsaber in which the color of the saber is dependent on what kyber crystal is installed. I think the RFID module you linked is SPI so technically you can have more than one on the bus, with each module on their own slave select pin.

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That is the trick!

One that uses a small coil.

And the software to go with it. :thinking:

A couple of inches for those cards which integrate the coil, is probably OK, particularly if the tag will be exactly parallel to it.

The common request here is for a reader which will detect tags up to a foot away (or even more!), requiring a large coil at least. Your requirement is the very opposite. :grin:

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Haha! Yea I know right?! Everything I keep finding on sites are about how far the signal will travel. It's like, no! I need the opposite! It does seem like there are smaller readers out there, but as one would expect, the smaller the reader, the higher the price.

One thing I've been curious about though is if I get something like this:

https://www.ebay.com/itm/324737040405?_trkparms=ispr%3D1&hash=item4b9bd60015:g:vbAAAOSwJ6tfAaVW&amdata=enc%3AAQAGAAAA4PBAQdZekoSkbcrI1oBZyIol5yCo2XStV2ysS6Fbb0OuzxtiXGa%2FJ5%2BIQo8hhhXcvvIqjKhleNAYZGKncqliHaGnmnGkzTe6iHshT2BizlX4LYu1ShfqhWyMlTrxbJU0gO2%2BDCjEk%2B9dDZYDErS5RYO4PkYJIvkr5Hzz2HSqBDts6e778zX6whjkbuItdQe4I2R2IdETO7jSAvZlXXR947QnhUAJNokgUzyiJ5lqvyXVhylO5Hv0W8BhQ%2FH6XniXRekJjPJPJz%2Bhonl%2BhrGH3fT9Y7p%2FCAy%2FbUfFoahjSgEG|tkp%3ABFBMjtaXirpf

Are these wired antennas able to be modified at all? Like, could I unwind it and then rewind it so that it was a smaller circle? Something that wasn't such a large rectangular shape? I don't see why it wouldn't work, but I wasn't sure if that specific shape was designed a certain way for the radio waves or something? Some of the cards have circular wires and others have big rectangle wires. Not sure if the shapes of the antenna matter or if it just needs to be wrapped in a certain direction. I guess they're only $6, so I could always just get one and try it out.

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And the larger the coil, the higher the price. This is commonly referred to as a "J-curve".

Only if you have the necessary instrumentation to measure its inductance before and after you make the modification. You may (will) need longer or shorter wire - I can't quite recall which.

This is because it combines with the capacitors on the PCB to form a circuit tuned to the operating frequency. It may be possible to change the capacitors, but you would still need instrumentation of some sort.

Shape makes a slight difference.

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I found this post after googling RFID kyber crystal. I have made a similar project already. I only designed it to read 1 crystal at a time. However i added in a function to change Phillips hue lights to the color of the crystal.
The housing that it is all in could probably be shrunk by 1/2 ish but I could not imagine going much smaller. I am a novice at best so take the following for what it is…. The most difficult parts were:

  1. Converting the 1s and 0s coming out of the RFID readers into real numbers. I had to dive deep down the rabbit hole to figure that one out. Once you get the “number” it was easy to figure out what crystal was in the reader.
  2. I did not realize there were 3.3v and 5v arduinos. The rfid reader I chose was 5v, the arduino was 3.3v. After countless hours wasted on this i realized I needed a level shifter. I was trying to use a small board that had Wi-Fi and they all seem to be 3.3 v. If possible try to keep everything using the same voltage.
  3. The API call to the hue bridge. Ugh…… I finally got a working simulation but it is slow.

Anyhow if you are still interested in doing this post a reply, I may be able to help. It has been over a year so it is not as fresh in my mind as it once was. Below is a video of what I made.

Kyber Light

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