Mechanical seven-segment display

[aeh5040]

Seven-segment numeric displays are found in clocks and calculators everywhere. Sometimes you will also see a mechanical one like this, where the segments take the form of physical objects. I decided to try making one of these. It counts from 0 to 9 by entirely mechanical means (just one motor). I think it's a safe bet that none of the real-life ones work quite like this! Although the idea is simple, it was quite difficult getting it to work well. Enjoy!

More pics: http://www.brickshelf.com/gallery/aeh/

Edited August 6, 2011 by aeh5040

[allanp]

Thanx for sharing, the video is mezmorizing!

[jorgeopesi]

No words... great...

[grohl]

This is... huge... this is... breathtaking... this is... absolutely stunning.

[Nazgarot]

Nice

[Zerobricks]

Wow! Thats so awesome!!!

[robuko]

Oh, beautiful! A Lego computer!

What a great build, wonderful execution

[vmln8r]

Simply brilliant. Well done

[Sokratesz]

Impressive :)

[Moz]

That's great.

Did you start with the idea of a music box or the Jaquard loom? Either would be cool. Of course, even cooler would have been just gearing things directly so it worked, but that would be in the "unfathomably cool work of genius" category (ie, I don't think it's possible)

[Erik Leppen]

Aaahh! I tried multiple times creating exactly such a thing... I never succeeded, things got way too complex to work. So I know how difficult it can be to build this. Even though it looks very simple in the video... I like how the thing works so quickly and smoothly. Great job!

I see how you did get the same idea of using the chain links to get ten sections on the cylinder

Now combine it with my counting machine mechanism to get multiple digits so you can count to 99

[basbase]

Very cool device. I like how you implemented the music box roller.

[timslegos]

Thats really awesome!! I cant imagine how long it took to coordinate all the links on the rotating drum.

tim

[Milan]

Very intelligently built!

Bravo!

[Jonas]

This is the sort of MOCs that I like most. Take Lego bricks and make something unusual or unexpectable from them.

You did it and you have done it in wonderful way.

Who would think, that one can make a 7-segment display from Lego and, even more, program it to count - all in pure mechanic way.

Excellent work!

[Seluryar]

love it!

[roamingstop]

Amazing... but for the next challenge; Hexadecimal

[aeh5040]

Wow, thank you for all the kind words, folks!

Moz: Did you start with the idea of a music box or the Jaquard loom?

Not specifically, but I guess such things were in the back of my mind!

Eric Leppen: Now combine it with my counting machine mechanism to get multiple digits so you can count to 99

Indeed, that would be very cool! I have thought a bit about this, and it would be quite a challenge. The "incrementing mechanism" that moves the 10's cylinder would need to be very strong and precise in order to overcome the friction and move it by the right amount (and, with the current implementation, at the right speed - otherwise the segments don't always flip all the way). Then there is the problem of how to place the two digits so all the input axles are accessible, without adding too much friction....

roamingstudio: Amazing... but for the next challenge; Hexadecimal

Actually, that should not be too hard. Instead of the circular drum you can just have a length of chain going round two sprockets, with 16 links (or 32 if that doesn't fit). Similarly, one could make it spell out any message that uses 7-segment characters.

[aeh5040]

Here are a couple of possible improvements that I might try to make it more reliable (this would be a good idea before attempting a 2-digit one, etc.)

1. As pointed out recently in another thread, the knob wheels are a little temperamental as spur gears. I used them in the display because 16t gears don't seem to exist in black. However, I now see that I could do the same thing with three 12t double bevels - this would probably work better.

2. Mathematically the 2:1 ratio of the 24t:12t gears is correct: the cams turn 90 degrees, and the segments turn 180. However, in practice there is a bit of slop in various places, with the result that sometimes the segments do not flip all the way over - it requires very careful adjustment to avoid this. So possibly a 3:1 gear ratio might work better...

[AussieJimbo]

Fantastic creation.

A really effective solution to a very challenging problem. Top job.

:classic:

Edited August 7, 2011 by AussieJimbo

[22kane]

Something about this just really brought me back to my childhood. It almost reminds me of those old science kits my brother and I had as children. You could make all kinds of weird machines to tell time or pick up radio frequencies and so on. I can tell you definitely put some work into this and it's very cool. I would frame it somehow and hang it on the wall as a "working" art piece. I could imagine the noise from the motors would get annoying after a while though. Nice job, I really enjoyed this.

[P4trickvH]

Very nicely done.

[Jim]

Awesome! Very cool indeed.

Wouldn't it be great if Lego would release a Technic set without wheels or treads. Some kind of machine or contraption.

[bord4kop]

This is stunning!

Looks simple, but it is not. The thing works so nice.. I am very impressed!

:thumbup: :thumbup:

[Tadej]

Great idea and really well executed, but have you considered also doing a two digit display that counts to 99, that probably wouldn`t be hard to make since you have the basic principle figured out.