LED Dot Matrix
An LED dot matrix is a grid of LEDs arranged in rows and columns for simple icons, patterns, letters, and animations.
Part images
What it is
An LED dot matrix is a grid of LEDs arranged in rows and columns for simple icons, patterns, letters, and animations.
How students use it
Students scan rows and columns rapidly, often using two 74HC595 chips to control the matrix with fewer Pico pins.
Pins and power
Pins 1-16 map to ROW and COL lines. SunFounder lists COL pins 13, 3, 4, 10, 6, 11, 15, 16 and ROW pins 9, 14, 8, 12, 1, 7, 2, 5.
The kit uses a CA dot matrix labeled 788BS. Current limiting and scan timing are required.
SunFounder states this kit uses a common-anode 788BS matrix. For the top-left LED, set ROW 1 high and COL 1 low; for common cathode the logic is opposite.
Voltage and safety
The matrix can light many LEDs, so current-limiting and duty cycle matter.
Avoid static all-on patterns without current planning.
Module internals
Main component: 788BS common-anode LED dot matrix, identified by SunFounder.
An 8x8 grid of LED junctions sharing row and column lines. SunFounder examples use two 74HC595 chips: one for rows and one for columns.
Datasheet notes
The visible part marking is 788BS per SunFounder. Verify the matrix label and common-anode/common-cathode type before using any generic dot-matrix datasheet.
Common libraries
No special library is required for the raw matrix; students usually write row/column scan code using GPIO or 74HC595 helper functions.
Common mistakes
Using common-cathode logic on the common-anode 788BS, rotating the pin numbering, scanning too slowly, and forgetting current limits when many pixels appear lit.