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Ledcat is simple utility that aims to provide a standard interface for driving LED-strips and such.

Simply create a program that outputs 3 bytes of RGB for each pixel in your strip.



The easiest way to install Ledcat is to download a binary from Github.

Note: Hzeller's LED Matrix driver is not available from CI builds.

Installing from Cargo

Install the Rust Language if you have not already.

Then, you can install ledcat directly using Cargo.

cargo install ledcat

Building Manually

Alternatively, you can build and install Ledcat manually:

git clone
cd ledcat
cargo build --release
cp target/release/ledcat /usr/local/bin/ledcat

Usage Examples

# Make a strip of 30 apa102 leds all red.
perl -e 'print "\xff\x00\x00" x 30' | ledcat --geometry 30 apa102 > /dev/spidev0.0
# Receive frames over UDP.
nc -ul 1337 | ledcat --geometry 30 apa102 > /dev/spidev0.0
# Load an image named "image.png", resize it to fit the size of the display and
# send it to a ledstrip zigzagged over the Y-axis.
convert image.png -resize 75x8! -depth 8 RGB:- | \
    ledcat --geometry 75x8 --transpose zigzag_y apa102 > /dev/spidev0.0
# A clock on a zigzagged two dimensional display of 75x8 pixels
while true; do
    convert -background black -fill cyan -font Courier -pointsize 8 \
        -size 75x8 -gravity center -depth 8 caption:"$(date +%T)" RGB:-
    sleep 1;
done | ledcat --geometry 75x16 --transpose zigzag_y apa102 > /dev/spidev0.0;
# Show random noise as ambient lighting or priority messages if there are any.
mkfifo /tmp/ambient
mkfifo /tmp/messages
cat /dev/urandom > /tmp/ambient &
./my_messages > /tmp/messages &
ledcat --input /tmp/ambient /tmp/messages --exit never --geometry 30 apa102 > /dev/spidev0.0

Supported Drivers:

  • Linux spidev
  • Serial
  • Artnet DMX

Supported Device Types: