I wanted to make my own big 7-segment digits for a long time now. I had some ideas how to do them differently. During the process I came to the conclusion that the standard 7-segment display isn't that bad :) . I did have to change something so I ended up with a 29-segment digit.
I am really happy how it turned out.

To play with the digits, I made myself a clock that can also be used as a timer. I want to use it as a "TED-talk" timer. For this it should count down from 18 minutes.
For an other project I need a clock that can count backwards, so this clock must also be able to do that.
Finally it would also be nice when I can use this as a normal clock. Because I couldn't figure out how and where to put the buttons, I decided to make an android app to set the clock through a bluetooth connection.

What makes this special?
I think the digits look really nice, much nicer than normal 7 segment digits. Besides the numbers from 0 to 9, this digits can also display a lot of letters:
It can't display:
So you can create a lot of words as long as they aren't longer than the amount of digits in the clock. In my case that would be max. four letters.
The app and the bluetooth connection give it great potential for different functions and placement at out of reach locations.

Special tools
To make the digits I used a 3D-printer. I can't think of an easy way to make them by hand. With a CNC, you could probably also make them. 3D printers are not so expensive anymore. I bought mine for less than 500,- and there is a printer in development for less then 100,- (the peachy printer)
For the lenses a laser cutter would have been great, but because I don't have one, I made them by hand.
You also will need a smartphone for the Android app to set the clock.

Text vs pictures
In the text I try to explain all the steps, but you probably will understand most of the process by looking at the pictures and reading the comments in the pictures. Be sure to read those! Most of the time they explain more than the text alone.

Before you try to make this clock, you should have some basic soldering skills. (you will need to solder like 250 wires and some components) You should be able to understand a simple electronic schematic. This shouldn't be your first ever Arduino project. Some experience in 3D-drawing and printing would also be nice. When you want to ad your own functions it is helpful when you have some experience in MIT app inventor or some other skills in building Android apps.

Step 1: You will need


  • 120 3mm LED's (I used blue ones)
  • 120 resistors (to go with the LED's)
  • 16 shift registers (like a HEF4094BP or a74HC595)
  • Wire
  • Arduino
  • Experiment PCB's (perfboard)
  • 8 1uf capacitors
  • Bluetooth module
  • 10 k resistor
  • 20 k resistor (or two 10 k resistors)
  • some small heat shrink tubing
  • 6 5mm LED's (I used 3 red, 1 yellow, 1 green and 1 green)
  • 6 resistors (to go with the 6 LED's
  • Buzzer
  • 44 female headers
  • loads of male headers
  • Push button that is normally on

  • Fillament for 3d-printer
  • 2mm transparant acryl

  • Wood
  • Plastic
  • screws

Bluetooth app
  • Android smartphone
  • MIT app inventor account

  • 3d printer
  • hobby-knife
  • guide
  • sharpy
  • snipper
  • drill(press)
  • 3 mm drill
  • computer with Arduino and 3d software
  • sand paper
  • file
  • needle nose pliers
  • soldering iron
  • 5 volt power
  • (hot) glue

<p>made IT!!!</p>
<p>Yeah great job! I'm impressed!</p>
Thanks to you.. I can now cpmplete my microprocessor project.... But did you edit the code? The hour command is not functioning properly<br>....
<p>I build it as a timer and a backwards counting clock for a camp-weekend, but I didn't have problems with the hour command. I just updated my mac to Yosemite and now I don't get Arduino working yet, so I can't see what's wrong... Can you tell what isn't working? So I can check when I get Arduino working again.</p>
<p>Very unique design of segment display, hope to see more from you :D</p>
Great, but a lot of work. I would use some bcd-7 segment converter
That would definitely be much easier, but what is the fun in easy? :)

About This Instructable


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Bio: I'm a social-worker, working with 12 - 23 year-olds. I used to be a printer and I worked voluntarily in Romania for a couple of ... More »
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