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Describe the most ambitious DIY project you’ve ever taken on.

My college final. At the beginning of our final semester, teacher assigned finals to each student. You could select any project you wanted. Most students were doing pre-built electronics kits from Radio Shack (yes you know how old I am now). AM/FM radio’s were really a popular choice. I decided that I was going to build a project from scratch.

In a way, to me, the self-DIY kits were sort of cheating. All you had to do was solder the right components in (in the correct direction for certain parts), and you were done. The hardest part about that was getting resonant circuitry tuned correctly.

I built a solar-powered calculator with its own storage batteries, as well as it would run off of 2 AA batteries.

Calculator was fully functional with 10-8 man LED displays, solar array, on/off switch.

Calculator had all the normal number buttons, 0-9, negative/positive conversion, save to memory, recall from memory, clear from memory, clear current calculation, and decimal point.

Functions, you could add, subtract, divide, multiply, as well as the equals button.

It was 100% built on a series of breadboards, which carried all of the circuitry to power the calculator.

In the middle of the calculator was an Intel 8080.

The code for the entire device was written in assembly language which handled all the routines and functions.

The 8080 was programmed to handle all of the system functionality of the calculator itself. It drove the logic to push the mathematical equations to the displays. Was the main storage point for on-board memory, which was a total of 64k. It handled/stored all the code written to make the calculator work.

The extra credit piece I tried to get working was a “speech” module where it would talk. Kind of like a speak and math. It I was unable to finish that portion of the calculator. (Ran out of time)

The easiest part was powering the calculator. Circuitry was built to handle incoming power from the small solar display, or choose to utilize the battery power automatically.

The hardest part, was assembly language.

The main off/on switch would clear all volatile memory (outputs stored) then power down.

Needless to say, I got an A.