Compact USB Clock (Buildlog)

This is just a rough rundown that documents a simple project- there's not much here in the way of a tutorial but you could reference this article if you're trying to build or troubleshoot your own C51 YSZ-4 clock. I bought this kit from originally to learn more about how to drive 7-segment displays and the components necessary to practically implement one that functions in some basic way. This ended up being a project partially used to help teach my girlfriend how to solder, as the board is laid out very well for entry level through-hole (THT) soldering.

This kit is a C51 YSZ-4 clock with an 89C2051 microcontroller that powers all the clock functions. Otherwise, the kit consists of:

-2x 10k resistors

-2x 30pF capacitors

-1x 104P capacitor (0.1uF)

-1x 10uF capacitor

-1x 1k PR1 parallel resistor (8x 1k resistors in a single package)

-1x 12Mhz crystal oscillator

-1x S8550 transistor

-2x momentary button switches

-1x connection box (for power input)

-1x 4 character 7-segment display

-1x PCB

-1x speaker unit

-1x 20-pin DIP riser for 89C2051

NOTE: This is one of my legacy projects that shows just the finished product, as I'm building this site out to document projects I completed in the past, but moving forward now that I have this site, I'm going to be working on walkthroughs that go step by step. All my 'legacy projects' that I only have the finished products of without walkthrough, will be notated with "(BuildLog)" in the titles.

Completed clock rigged to a variable PSU to test functionality. It works!

^Completed clock with power off.

^The solder joints are easy to make as the holes are very forgiving and large, giving you tons of surface area to get the components correctly seated and connected.

^I rigged an old USB cable I had to the + and - DC terminals (the signal wires aren't needed for this application) so I could make the clock USB-powered.

^One of my first 3D prints as well, with two long cylindrical buttons to change the clock settings. This was during a time when I was learning a lot of concepts pretty rapidly, after I printed the case and got to this point, I got sidetracked and moved on to another quick soldering project soon after. Looking back at this, I might just come back to it and refine the case with a nicer design and logo, and get everything sealed up to run permanently.

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