Customisable Mechanicle 7-Segment Display

I have been away for a few days so I couldn’t do a lot of things. But as soon as I came back,I started working on this project again. In this devlog I will talk about the designing of the custom cam pieces

Design

To start, I want to say there is a lot of custom pieces in this cam system. This is caused by 3 factors that I will list now.

▪There are a total of 9 cam shafts,8 normal (3-10) and 1 special case (2).

▪There are 5 different cam pieces per cam per shaft. Except the shaft No.2

▪There are 2 cams needed to show a number. 1 turner and 1 aligner. Except the shaft No.2

With these we can calculate the amount of cam pieces needed with the equation below.

(852)+(121) = 82

-How To Use The Cam Pieces-

There are 10 pieces per cam shaft except the No.2. I will write how to use the shaft No.2 at the end.

We can divide these pieces to 2 seperate groups called turner and aligner.
Every turner piece has a corresponding aligner piece. When you put the turner pieces the corresponding aligner pieces come to the opposite side.

The important ones are the turner ones. And the 5 turner pieces are named:

▪On

▪On,Single

▪On,Left

▪On,Rigth

▪Off

Each turner cam has a specific rule to follow.

The piece, “On”, is used when the left and right neighbours of the piece are a type of on.

The piece, “On,Left”, is used when the piece has a left neighbour that is a type of on.

The piece, “On,Rigth”, is used when the piece has a right neighbour that is a type of on.

The piece, “On,Single”, is used when the piece has no neighbours that are a type of on.

The piece, “Off”, is used when the piece is supposed to be off (The segment is closed). This piece is used in places that are not a type of on.

Before doing anything, you have to decide when the connected segment will be open or closed. the segments are normally closed like in the number 8. (Closed means that they are shown and open means otherwise.)

To give an example I will use the cam shaft No.8

If I want an configuration like this:

XOXXXOXO or

    X  O

 O         X

 X          X

    O   X

I have to put the pieces like this

“On,Single”, “Off”, “On,Left”, “On”, “On,Rigth”, “Off”, “On,Single”, “Off”

After doing this your turner layer will be ready, now you can place the corresponding aligner pieces at the opposite side.

As I said all turner pieces have a corresponding piece, you just have to take these pieces and put it at the exact opposite side.

After doing 1 turner and 1 aligner cam you have to place a spacer ring to space the cams apart. I didn’t modelled the spacer rings yet but they are pretty easy.

Do this for every segment and you are DONE

-The Cam Shaft No.2-

There isn’t a lot of things to do in here. There is just Three pieces: “On”, “Off” and “On,Single”.

You do the thing nearly the same except you don’t have the complected pieces like “On,Left”.

If you do want it to be on, you put the piece “On,Single” and if you don’t you put the piece “Off”. If you want all of it to be on you just put the piece “On” to both of the places.

I didn’t finished modeling these yet but I’ll keep you updated.

My Future Plans

▪Make an servo attachment and code it.

▪Test every cam piece mechanically in Autodesk Fusion.

▪Build it out of cartboard or find a place to 3d print.

I know that this has been an LONG devlog but it is the main part of this project. If you read all of it THANKS A LOT.

Also I will work on this project in the Forge YSWS from now on
İyi Akşamlar! Good Night!

DEVLOG #004

Hi everybody! Hope y’all are alright :)
My last devlog was 4 days ago, since then I worked on an important part of the project. Displaying big numbers that are more than 1 digit. I called the big number system.

Design

As I said I generally worked on the big numbers system but I also designed some more useful things that I will mention right now.

-Numbers that are more than 1 digit-

Most of the 7 segment displays use more than 1 motor (a motor per digit) when used dise by side, this looks a lot cleaner as a display, however it makes the total cost and total work a lot more. Because you have to code, connect it to a microcontroller, solder the motors for energy (as far as I know microcontrollers can’t supply electricity more than 2 motors simultaneously.)
Some people might not want to do all of this stuff. For them I designed a 10:1 gear ratio with a geneva mechanism. This enables you, to put the displays side by side and only need 1 -more powerful- motor.
This system works for all displays that includes 10 different symbols (numbers) in the cam system. (There is some modification needed if you want to do the same with the displays that include 3,4,5,6,7,8 or 9 symbols. I will mention this later in this devlog.)

-A step towards customisability-

I designed the 8 different cam shafts that allows the pieces (arcs and curves) to be inserted at the sides, making it customisable. All of these 8 different cam shafts have different number of sides(3,4,5,6,7,8,9,10). So they can be used to limit how many symbols are in the circulation in the display system. For example if you want only the numbers 0,2,5,8 to show up you can use the 4 numbered cam shaft and customise it to show the numbers you want. This gets rid of the need to turn more than 36 degrees (1/10 of the full rotation, the cam shaft number 10 uses this (Cam shaft number 10 is the shaft if you want to use all digits 0-9)) if you want to go from 5 to 8 for example.

I didn’t designed the arc and curve pieces yet but they will be my priority in the future.

-The Clock System-

You can make the clock system as a big number system using motors (1 per display), but as I said that can bring a lot of work.
If you don’t want to do all of that work, you can make use of the 10:1 gear ratio and a new module that turns the 10:1 gear ratio to 6:1 .
10:1 gear ratio will be used between, for example, units place of minutes and tens place of the minutes. And the 6:1 gear ration will be used between the seconds and the minutes and between the minutes and the hours.
The 10:1 and 6:1 gear ratios combine to make a 60:1 gear ration that is the exact ratio of the seconds to minutes or minutes to hours.
But with this you also have to change the cam shafts of the tens place of the seconds minutes and hours to cam shaft number 6 , so that they only have digits 0-5.

If this seems like a lot of work yes it is. But i will also make the design of the needed cams for the cam shaft number 6. So you don’t have to customise yourself.

-Last few things-

I designed a connector to attach more than 1 display side by side.
I also customised the connector to be a colon(:),a dot(.) or a comma(,). You can use these as to represent numbers like 12.35 and 14,85 or hours like 13 : 11.

Future Plans

▪Build it from cardboard
▪Make a servo attachment and the code for the clock system.
▪Make the custom pieces for every shaft.

I also want to mention that there will be A LOT of part files for this project, cause every cam shaft requires a different width for the custom pieces.

I finally finished writing this devlog. I might speaked a lot more than needed but thats on me sorry :) Also for all the fellow readers that read all of this devlog. Thanks A LOT :):).

Kendinize iyi bakın. See you laterr.

Devlog #003

Hello everybody! (For the second time today)

I am writing this as a mini devlog to introduce my banner and log my time. Also I am writing this at 3.10 my local time so I am pretty tired.

After working on this for a few hours -2 hours timelapsed+ some extra- in Blender I managed to satisfy myself with the image I rendered. This, with completing my project page, gave me a reason to escape from designing.

With this I finished a thing on my to-do list. It is getting smaller and smaller as the time goes on :)

After that said, I don’t really have much else to say/write here.

If you guys have any idea about what I can change please inform me.

İyi Geceler. Good Night!

DEVLOG #002

Hi everybody!
Last 2 days I have spent WAY more time on things than I expected to spent. But, because this project it pretty fun for me, that wasn’t really a problem : )

Also I am trying to learn, how to make my devlogs enjoyable to read. If you have any ideas or suggestion for me please dm me or mention it in the discussion ( comments) part of this devlog.

Now I should probably mention what I did :]

Design

As I mentioned on my first devlog, I wanted this display to be 3D-Printable. So I mainly worked on that and a few other things.

-Making it 3D printable-

Added pins and slots for each of the 7 segments.

Modyfied the shaft that turns the cams, so that it is easier to assemble.

Added a spring system so when the knob is turned for every number the cams click in to the place. (Yes that satisfying * click *)

Adjusted the knob to no need any glue.

-Some other few things-

Made the shaft that turns the cams a square so that it can rotate the cams without glue(x2).

Made cam spacers to space out the cams and to not need glue(x3).

Made an honeycomb design on two of the faces of the box. This makes it lighter, less materials to print and I also think that it looks cooler.

My plans for the future days

▪Design a banner for the projects stardance page.
▪Make it customisable via some curve and arc pieces
▪Build it from cardboard
▪Make an attachment for the clock (A Geneva mechanism)
▪Make a servo attachment and the code for the clock feature.

Yes, this devlog was mainly about not using any glue.
I specifically wanted to resolve this issue, because i don’t really want to use anything that is not 3D printable, unless, it is a non negotionable (like servo motors).

Also please tell me if I can change anyting about my devlogs to make it more enjoyable.

Görüşmek Üzere. Byeee

DEVLOG #001

Hi everybody! Last few days, I have been working on a 7-segment display that uses customisable rotating cams. I found hackclub 3 days ago so I couldn’t log all my progress into the system. Because of that I want to give a little journal to adress what I have been working on.
Also I want to mention because this project is “mechanical” I will generally write about the designing, building and trouble shooting phase.

July 1 - July 6

My first experience with Fusion.
I designed the main system of the 7-segment display (7 segments, rack and pinions , the box and most importantly the base₁₀ cams.)
There were some problems in some of the cams, so I remodeled some of them. And it worked. But due to the Fusion July 2026 update I can’t simulate the cams rn on my computer ( It bugged a bit)

July 6 - July 9 (Today)

I tried for more than 2 hours to solve the issue with Fusion, but sadly, I wasn’t successful.

I also designed the rotary knob to control the design. But it might need some adjustments in the future.

My plans for the future days

▪Make it customisable via some curve and arc pieces

▪Make it 3D printer friendly

▪Build it from cardboard

▪Make an attachment for the clock (A Geneva mechanism)

▪Make a servo attachment and the code for that

My project might seem similar to Engineezy’s 7-segment display, It’s cause thats what gave me the idea of starting this project.
Altough it might seem similar, the internal mechanism will have some changes. It will be like a modded version even though I don’t have the CAD files for his project, I only looked to his videos that is available on his youtube.