Cat printer is a portable thermal printer sold on AliExpress for around $20.
This repository contains Python code for talking to the cat printer over Bluetooth Low Energy (BLE). The code has been reverse engineered from the official Android app.
# Clone the repository.
$ git clone git@github.com:rbaron/catprinter.git
$ cd catprinter
# Create a virtualenv on venv/ and activate it.
$ virtualenv --python=python3 venv
$ source venv/bin/activate
# Install requirements from requirements.txt.
$ pip install -r requirements.txt
$ ./print.py --help
usage: print.py [-h] [-l {debug,info,warn,error}] [-b {mean-threshold,floyd-steinberg,atkinson,halftone,none}] [-s] [-d DEVICE] [-e ENERGY]
filename
prints an image on your cat thermal printer
positional arguments:
filename
options:
-h, --help show this help message and exit
-l {debug,info,warn,error}, --log-level {debug,info,warn,error}
-b {mean-threshold,floyd-steinberg,atkinson,halftone,none}, --img-binarization-algo {mean-threshold,floyd-steinberg,atkinson,halftone,none}
Which image binarization algorithm to use. If 'none' is used, no binarization will be used. In this case the image has to
have a width of 384 px.
-s, --show-preview If set, displays the final image and asks the user for confirmation before printing.
-d DEVICE, --device DEVICE
The printer's Bluetooth Low Energy (BLE) address (MAC address on Linux; UUID on macOS) or advertisement name (e.g.:
"GT01", "GB02", "GB03"). If omitted, the the script will try to auto discover the printer based on its advertised BLE
services.
-e ENERGY, --energy ENERGY
Thermal energy. Between 0x0000 (light) and 0xffff (darker, default).
% ./print.py --show-preview test.png
β³ Applying Floyd-Steinberg dithering to image...
β
Done.
βΉοΈ Displaying preview.
π€ Go ahead with print? [Y/n]?
β
Read image: (42, 384) (h, w) pixels
β
Generated BLE commands: 2353 bytes
β³ Looking for a BLE device named GT01...
β
Got it. Address: 09480C21-65B5-477B-B475-C797CD0D6B1C: GT01
β³ Connecting to 09480C21-65B5-477B-B475-C797CD0D6B1C: GT01...
β
Connected: True; MTU: 104
β³ Sending 2353 bytes of data in chunks of 101 bytes...
β
Done.
Mean Threshold:
Floyd Steinberg (default):
Atkinson:
Halftone dithering:
None (image must be 384px wide):