Electronics Project #10: TJ-56-428 4-Digit Digital DIY Clock | In The Lab With Jay Jay

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Silly Job Title: Switch Sleuth

Happy New Year!

In this video, my first video for 2025, I construct a 4-digit digital clock I recently purchased from AliExpress: TJ-56-428 4-Digit Digital DIY Clock Kits with Acrylic Shell, DIY Alarm Clock Soldering Practice Kit for Learning Electronics.

I thought it might be nice to kick off the new year with an actual electronics project, as that is what this channel is supposed to be mostly about!

I translated the instructions from Chinese to English, and those are here: TJ-56-428. These include instructions for use of the complete and fully assembled clock.

This was a great chance to try out my new METCAL PS-900 Soldering Station and I am pleased to report that I am very happy with my new soldering iron! It is a pleasure to use.

The heart of this circuit is the STC15W404AS which is a microcontroller! It has been pre-programmed with the clock functionality, there was no software or source code that shipped with the kit.

Update: my mate @sadata777 pointed out that there was a protective coating on the acrylic and I remove that in this video: https://youtu.be/y9btakLOCHc

Update: my mate Joe pointed out that I had the case on back-to-front which you can see me fix here: https://youtu.be/IyJ3IHgRfiw

Thanks very much for watching! And please remember to hit like and subscribe! :)


Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

Yum Cha IC Chip Pickup ToolThis is an image of the product.

Let’s go shopping!