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Project Notes

#620 Glowing Star SMD Practice Board

Testing the Five-Pointed Star SMD Practice Board with LM358 oscillator LED effects.


Here’s a quick demo..



I’ve seen this Five-Pointed Star Breathing Light DIY Kit around for some time, and finalled shelled out a $1 or so to try one out.

It’s maybe a change from the typical 4017+555 circuits used in these SMD soldering kits!

It is quite a nice little practice board for SMD soldering - or perhaps you are just after a twinkling star!



Item Ref Qty
22Ω R5 1
33kΩ R6 1
47kΩ R1,2,4 3
100kΩ R3 1
47µF C1 1
LM358 U1 1
8050-J3Y Q1 1
0805 LED LED1-20 20
power wires   2
PCB   1




The circuit is a simple OpAmp triangle-wave oscillator using a high-side NPN transistor to drive the LED array.




The Q1 base voltage over time - showing the triangle wave:



Haven’t done any hot air work for a while. Thought I’d do that rather than hand-solder. All good…

build_front build_rear

Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.