#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:

Notes

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).

Construction

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

Example Parts Sources on Aliexpress

• 74HC595 SOP16
• 220Ω 0805
• 220µF 16V 6x7mm SMD
• 0805 LEDs (5 colours)

Demo

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

Credits and References

• KiCad like a Pro - course materials
• KiCad
• gerblook - nice tool for testing a set of gerber files
• OSH Park
• HARDWARE HANGOUT with James “Laen” Neal from OSH Park! - where I first learned of OSH Park