Mom’s Alarm Clock

It was 1980 …

Palo Verde High School in Tucson, Arizona had an excellent Industrial Arts program. Years before, in the early sixties, the Tucson Independent School District had the foresight to offer training in many industrial trades, building our school with an external set of buildings for shop classes. We had auto, wood, welding, sheet metal, machine, and electronics shops. They didn’t call it a “magnet” school back then, they just started building them that way.

At registration, in the onset of my freshman year, I rushed across the cafeteria to trade computer punch cards with a teacher and enroll in the rotating program of courses that in my case started with electronics.

Yearbook picture of the Electronics Club

The semester began with lots of training on basic circuits followed by experiments at the school’s Lab-Volt benches. Near the end of the quarter, with all the basic stuff accomplished, it was time to construct our final project: An LED digital clock. Our teacher, Mr. Reynolds, explained that after our parents ponied up the cash, he’d order a clock module kit for each student from Digi-Key. Mom agreed to fund my endeavor, and I agreed to build her a digital clock!

I knew about Digi-Key already. Back then, the electronics magazines like Popular Electronics had mail-in cards inserted in them where you’d circle a few numbers, send them back to the publisher, and the corresponding companies would send you their catalog or information on. Free stuff in the mail! Yes, I was already getting the Digi-Key catalogs, but this would be the first of many components I’d actually receive from them.

A 1979 Digi-Key ad for the clock modules and kits

The kits themselves were pretty basic. You’d get a National Semiconductor MA1023 clock module, a transformer, and four pushbutton switches. What you did from there was up to you. Assembly involved soldering and wiring the switches and transformer to the module and then wiring the transformer to an AC cord. My personal customization was to add a speaker and volume pot to make it an alarm clock.

Mr Reynolds required that we make or modify some kind of enclosure for the project. I think most students used the standard plastic enclosures with metal lids that they drilled, cut, and filed to suit.

For my enclosure, I chose to bend some yellow sheet plastic into a three sided C-shape. First I drilled the holes and made the cutout for the display bezel. Then I used a plastic bender/folder fabricated by our sheet metal and drafting teacher, Mr. Mentzer. That was made from a refrigerator defroster heating element and some heat retardant panels. At home, I hand crafted the pine sides using a jigsaw, router, and belt sander.

The clock module in back, speaker and switches up top, the volume pot to the left and the AC transformer to the right
The switch on the volume knob enabled the alarm.
You can see the MA1023 model number stamped in white on the PCB.
I made this vented back from uncoated masonite and covered the speaker with some printed fabric from Mom’s sewing notions. An underwriters knot was used as an internal strain relief for the the power cord

I was pretty proud of the work I did on that early project. Mom used it for years, and it still works great today.

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