Jason Krizan orthorhombic

Controlling the Brother P-Touch Cube label maker from a computer

The Brother PTP300BT label maker is intended to be controlled using the official Brother P-Touch Design & Print iOS/Android app. The app has arbitrary limits on what you can print (1 text object and up to 3 preset icons), so I thought it would be a fun challenge to reverse engineer the protocol to print whatever I wanted.

Python code at the bottom if you want to skip the fine details.

Process

Intitially I had a quick peek at the Android APK to see if there was any useful information inside. The code that handles the communication with the printer in Print&Design turned out to be a native library, but the app clearly prepares a bitmap image and passes it to this native library for printing. Bitmaps are definitely something we can work with.

	import os
	import requests
	import time
	import sys

	video_quality = "540p" # available qualities 360p, 540p, 720p

	"""
	In order to get courseId go to a course page open network tab in browser dev tools and search for "onDemandSpecializations"
	in search input of network tab and then go to videos section of say week 1 , check the query param "courseId" its value is what we use can use as value for "one_of_specialization_course_id"