Instructables

Programmable watch with four character display

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You'll be the talk of the town when you wear this obnoxious, oversized, completely impractical wristwatch. Display your favourite foul language, song lyrics, prime numbers, etc.

Inspired by the Microreader kit, I decided to make a giant watch using similar sixteen segment displays. Twelve hours later, I came out of my masochistic fugue and stopped trying to route a sixteen bit data bus on a single sided pcb small enough to wear on your wrist.

Returning to my digikey box of mystery, I came up with a four character display made up of 5x7 led matrices. 7 bit parallel data input, no need for umpteen current limiting resistors, upper and lower case characters, the rest writes itself.

This instructable is not meant to be a tutorial on creating PCBs or programming PICs. In all fairness, I wouldn't actually recommend that anyone try to make one of these. If you know enough to follow along, you can probably do a better job than I did. If you don't know what's going on, then this instructable isn't going to teach you all you need to know.

P.S. If you use this to scroll internet catchphrases in public, you are a bad person and should be ashamed.
 
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Jams905 years ago
i wanna see the video... please upload it again ;)
yeah
n0ukf6 years ago
There's something wrong with your video, the embedded player says "no longer available" and copy/pasting the url fails too.
robomaniac7 years ago
hello!

I first say this display in a micromouse Min4A
http://www.np.edu.sg/alpha/nbk/umouse/min4a.html

He use the SLR2016, it is much slimmer. It cost 20.78$ cdn
http://catalog.osram-os.com/media/_en/Graphics/00034123_0.pdf

the DLO3416 is 19.63$

The only drawback of this display is that you need a lot of I/O on your micro.
I think this is a great way to test your programming skill. You can code very crudelly or take the time to think and make something more effecient.

I would love and might give it a try! I got other projects to build and finish first ! :-)

Thanks!

Jerome
robomaniac7 years ago
Hello

Do you use the chip enables (CE1, CE2, CE3, CE4)?
I don't think you do. I was wondering what they do.

(D0-D6) is the desired data code and (A0, A1) digit address

How does A0 and A1 work?

Like this?
0 0 = first digit
0 1 = second digit
1 0 = third digit
1 1 = fouth digit

you select the digit and then write the ascii code on (D0-D6)
that seem simple!

you add the PWM on pin 14 ( BL) to dim or blink

thank you!

Jerome
deflater (author)  robomaniac7 years ago
The chip enables allow you to use more than one display on the same data bus. I have them tied high/low as needed to enable the chip at all times. If you wanted to use two displays, you would add another address line and tie it to an active high enable on one chip and an active low on the other. You've got the A0 and A1 bits right, it is pretty simple. The only other function is the cursor, which I haven't bothered with.