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Project Notes

#179 LEDx16Module

A custom 16 LED SMD PCB with 74HC595 shift register interface.

Here’s a quick video of the module running the demo code:



This is my version of project 3 from the KiCad like a Pro course from Tech Explorations.

The board exposes a dual 74HC595 shift register interface for microcontroller control of an array of 16 LEDs with current-limiting resistors.

The PCB design was done with KiCad.

I haven’t sent the boards for production yet - first sourcing and verifying the SMD components. When I’ve built and tested the board, I’ll update and share the OSH Park project and Arduino code.

I sent these off for production at OSH Park, and they turned out quite well. I think I could have picked a footprint for the SOP16 ships with longer pads to make them easier to solder by hand.

One variation I’ve made in the circuit from the KiCad like a Pro course: I’ve explicitly grounded pin 13 (output enable - active low). If left floating, I’ve found the circuit to be unreliable depending on power conditions (output enable floats high).


See the KiCad project for all the details. Here’s the result:

The Schematic


PCB render

Example Parts Sources on Aliexpress


The LEDx16Module.ino sketch runs a simple demo sequence on the board from an Aurduino using hardware SPI.




Credits and References

About LEAP#179 CMOS/TTLSMDArduino
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 my personal collection of electronics 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.