I admit it: I'm a total geek. I love electronics, programming, 3D art, vintage Apple hardware, and whisky. I'm always juggling half a dozen projects. I also enjoy documenting it all: my successes, my failures, my experiences... and everything geeky along the way.

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Upgrading My Old 7490 Clock, Part II | Kevin Rye.net - Main

Kevin Rye

Geek Extraordinaire. Yeh, I said it.

Upgrading My Old 7490 Clock, Part II

While my PCBs were being fabbed, I took the time to design a new laser-cut acrylic enclosure.

I first liberated the electronics from the old project box and took some measurements.


I then headed over to makercase.com and punched in my dimensions. That generated a nice looking .svg file.


I then imported that .svg file into Inkscape and put it on one of Ponoko's templates. I changed my lines to blue for cutting, added some text to be engraved, and added some holes for the power cord and set buttons.

Screen Shot 2014-05-21 at 10.59.28 PM

After about two weeks, my acrylic arrived by UPS. I swear, those guys are savages. It clearly states on the box to "DO NOT BEND". However, the box arrived folded in two places.

I crossed my fingers that they didn't snap the acrylic.

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They did snap it in half, but luckily it snapped right where I had cut it, so it broke right on a seam. The pieces were OK.

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I popped the pieces out and discarded the rest.

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They look really good, and fit together perfectly.

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I had chosen to etch the HOURS and MINUTES labels on the back. Now that I look at it, I should have raster filled them. Maybe I can fill it in with white paint.

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What a difference looking at them side-by-side. The new enclosure is way smaller than the last. If I got the dimensions right, the case should be no bigger than the PCB itself. The guts should fit like a glove.

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Boom! Nailed it! It's perfect!

7490fitslikegloveenclosure 01

I was originally going to make the enclosure either clear or semi-translucent. I decided against it in the end since the innards aren't that nice to look at. Usually, I like to showcase the design of the PCB, but since this was a hand-etched board cut with a Dremel, it's not very pretty looking. In addition, I want it to look as nice as possible so that my wife won't mind seeing it in the living room. I want it to look like a finished piece, and not like a prototype in a project box.

With that said, I somehow forgot to make a cutout for the display. I had it in my head the whole time that I didn't need to make a cutout because I’ll be able to see the LEDs through the acrylic. What was I thinking? I had already submitted the order, so it was too late to change it. I just hoped that even with black acrylic, I'd still be able to see the LEDs through it. Wishful thinking. It's as black as pitch.


Take two: GO!

I need to make a cutout for the front display, but while I'm at it, I'll raster fill the text on the back and add my name and date to the bottom. I like to think of my projects as works of art, so I like to sign them.


I then want to fill the cutout with a translucent red panel. I made a separate file for that. I'll probably hold it in place from the back with either some tape or a few drops of glue.

Screen Shot 2014-05-22 at 9.19.12 PM

Hopefully within a week or two I’ll have the PCBs and the acrylic. I can’t wait to finished this up. Then again, it’s been 13 years, so another week won’t kill me.

See this project from start to finish:
Digital Clock 1.0
Upgrading My Old 7490 Clock, Part I
Upgrading My Old 7490 Clock, Part II
Upgrading My Old 7490 Clock, Part III
Upgrading My Old 7490 Clock, Part IV
Upgrading My Old 7490 Clock, Part V