Tron Identity Disc

Tron is a science fiction franchise created by Steven Lisberger. The identity disc is seen as a key aspect to the franchise as the disc holds the identity of the program. The identity disc is sometimes referred to as a light disc. Some programs also use their light disc for combat, like Tron in the movies. The light disc sits on the back of the programs and there are a few different versions of the disc, each with there own colours. The main ones being black and blue for the civilians, orange for Clu, and white for Tron.

There is heaps of info out there about both, so feel free to have a look into it if you want to know more. Tron- Wikipedia

The Plan

I had to come up with a plan to complete this. This project would probably be one of the harder integration projects as it will be combining lots of different areas and skills to make this thing happen.

So here is the plan:

• Create a disc that looks pretty close to the movies, so its is easily recognisable.
• Addressable RGB LEDs everywhere
• Custom design circuit board
• Custom software to make the most of the disc

Now with some idea of what I want, I thought I would jump into the first task, designing the disc.

Mechanical Design

Prototype

I decided the best way to start the project would to be working on the physical disc. I scoured the internet to try and find information on the disc dimensions, and other details , with some luck to get me started.

After a few cardboard attempts at getting the right size, I went to a laser cut MDF template. This allowed me to check the sizing, within my hands, and across my back. The disc is made to fit myself rather than anyone, so some people that have different body dimensions may find the disc doesn’t fit them as comfortably. This gave me some rough dimensions of (223 223 34)mm , from that I rounded the numbers, to make dimensions appear nicer whilst designing, before jumping into the rest of the model. Leaving me with the current dimensions of 230mm diameter by 30mm thick.

3D Modelling

I decided upon using Fusion360 for this project, for a few reasons:
1. I can share the files around and work from different computers,
2. It is currently free, and as a student, I do love free things 🙂

Outer Shell

The majority of the disc was created with a revolve around the centre as I found that is the best option to create the general shape. I used Fusion’s inbuilt “shell” feature with the shell thickness set to 3mm creating the basic form of the disc. This took quite a few attempt to get to the final shape, with tweaking the revolve sketch dimensions and shape to get it all to fit together and look pretty close to the correct size.

The cut out sections for the lights were next. This comprised of a sketch with the desired shape with reference points of the shell to make sure it lines up in the desired locations. I extruded the sketch though to get the inner arc and the notches along the edge.

Next came arguably the hardest part.. the emboss. this was a tool I had never used before and previously was trying to use almost every other tool fusion had to over before discovering the emboss tool. I used the emboss too to add in the little details around the disc to make it look the part. Obviously the details aren’t extensive but I think still accurately represent the disc and concept.

I chose to leave out of of the main features on the disc, the inner connection markers. I chose this to give the disc a sleeker look, as well as to avoid the complexity of creating the notches. In an ideal world it would be possible to add them in, but I prefer the aesthetics without.

Light Diffusers

The next major part is the light diffusing sections. This includes the inner arc and the outer edge. The plan is to have these sections 3D printed using SLA, which means they will be returned at a high accuracy and tolerance. This meant I could model parts to fit exactly as I wanted and match the curves and angles of the disc so they appear as 1 section. A lot easier that sanding acrylic at a specific angle and requiring a jig.

Manufacture Concept

At the moment the plan is to 3D print most of the parts, if not all. With access to multiple printers I feel this will be a great way to prototype the disc before outsourcing to higher quality printers and parts, with the aim for the parts to be SLA printed for the high quality surface finish with little to no post processing on my end.

Challenges

The overall mechanical design was challenging. At time the software was not able to achieve the exact look I was after and I had to compromise. I guess that would be why most props are not designed in CAD completely and are sculpted.

Packaging

Arguably the hardest part. It was a nightmare trying to squeeze so much, yet so little into the space. Then knowing something would fit, the challenge would be making sure nothing hit anything else.

Connecting the halves

Connecting the two halves together. The first idea would be to glue them, but I felt that was not the best idea encase I wanted to open it up again to show off the insides or modify the disc in the future, so gluing was the last option.

The main PCB was to be screwed into the outer shell, this left consistent points for the two halves to line up. I decided to try a mix of press fit and magnets to attach the halves. With a magnet being glued into a post and that post sliding over the top of the screw. This may not be the best option, but I felt it was a sneaky way to make the disc be able to separate if I wanted to modify it in the future.

Symmetry

Symmetry was a big challenge. Due to the nature of the disc I and design effort, I wanted to make the disc as symmetric as possible. This would allow for less time developing different parts, as well as a more balanced disc. This was relatively easy for the outer shells as they were the same part right up until the end where a few modifications were necessary to connect pieces together.

Centring the main PCB was next and was relatively easy with the outer shells being the same, the catch was the lighting. If the lights sat on the top and bottom of the PCB there would be dark lines where the PCB was. I solved this by making cut-outs in the main circuit board for each LED. Now this probably isn’t the best idea but I am going for looks and believe the soldering effort will be worth it in the end.

What’s Next?

Since the majority of the shell for the disc has been made, my focus will shift to the electrical design. Since I will need to package everything inside the disc, I need to know what is going into it before finalising the shell, connections and other mechanical requirements. Keep an eye out for the next update about all of the electronics.

Note: Not everything created is a perfect representation of the franchise. Items created have been based on the franchise with the intent to create similar items with a personal twist.