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

This post is part of my video blog and you can find more information about this video over here.

You can support this channel on Patreon: patreon.com/JohnElliotV

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!

Magnetism Detector | Project 12/20 | Maxitronix 20in1 | Learning Electronics In The Lab With Jay Jay

This post is part of my video blog and you can find more information about this video over here.

You can support this channel on Patreon: patreon.com/JohnElliotV

In this video I do the 12th project from the Maxitronix 20in1 (the Sensor Robot 20): Magnetism Detector.

In this project we control a BJT transistor with a magnetic reed switch.

We use the thermal camera to observe heat in the transistors and LEDs during operation.

This is a plain DC circuit with no signals so there was no call for measuring anything with the oscilloscope.

I got myself a little confused about normally open and normally closed circuits during the video, but I think I was clear enough about that in the end.

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!

Yutiars Round Paint BrushesThis is an image of the product.notes

Let’s go shopping!

Equipment from Peak Electronic Design

The British company Peak Electronic Design has a wonderful range of Test Instruments.

Today I purchased these ones:

Still on my wish list is this one:

The reason for this particular splurge is that after I purchased my METCAL PS-900 Soldering Station element14 sent me an email with a coupon for 15% off. Since these Peak Atlas devices were on my wish list I figured I might as well get them while I can get 15% off.

Decade Resistor Box

I got two of these Resistance Box 0-9999.9Ω Adjustable Lab Resistor Substitution Box Precision 1W Variable Knob Switch Boxes from AliExpress, but they kind of suck a bit. The resistors are only 1/4 Watt, the precision only 5% or 10%, and I had to mod it myself to replace the terminals with banana sockets.

Today I came across Build a Pro Decade Resistor Box for Cheap! PCB & 3D Print Files Included which includes all the plans necessary to make my own resistor box and with 1 Watt resistors.

I might take this on some time.

Handling Cookies is a Minefield

I read an interesting article today Handling Cookies is a Minefield. It’s basically about what characters are supported in cookies across browsers and servers.

As a rule I only use two cookies: a session cookie, which identifies the session, and a persistent browser cookie, which identifies the user and their browser.

Extra Content #17: Video and Sound Test for New Maths Homework Videos | In The Lab With Jay Jay

This post is part of my video blog and you can find more information about this video over here.

You can support this channel on Patreon: patreon.com/JohnElliotV

In this video I prepare my video cameras and recording studio so I can record the new Maths Homework section of the show!

This is just some second channel content for the archives. The video quality is quite poor in the beginning but we figure it out by the end! Stand by for the introductory video to the new section of the show which will be coming out on the main channel soon!

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!

RELIFE RL-007GA Solder LugsThis is an image of the product.notes

Let’s go shopping!