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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

About LEAP#620 SMDOpAmp
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, 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 (IMHO!).

The projects are usually inspired by things found wild on the net, or ideas from the sources such as:

Feel free to borrow liberally, and if you spot any issues do let me know. See the individual projects for credits where due. There are even now a few projects contributed by others - send your own over in a pull request if you would also like to add to this collection.