stecman

Writing to LTO tape with a text index and a memory buffer

This script is for writing to LTO tape on Linux with tar and producing a plain text index file. It uses a large memory buffer to keep the destination tape drive fed when the source drive can't consistently match the tape's write speed (eg. when there are a mix of small and large files).

This was written for a small, manually managed tape collection. It writes tape index information and tar listings as text to a file. This file can be stored separately, searched easily, and appended to the end of the tape if you want your tapes to be self-describing:

stecman

-- LR imports
local LrApplication = import("LrApplication")
local LrApplicationView = import("LrApplicationView")
local LrBinding = import("LrBinding")
local LrDevelopController = import("LrDevelopController")
local LrDialogs = import("LrDialogs")
local LrExportSession = import("LrExportSession")
local LrFileUtils = import("LrFileUtils")
local LrFunctionContext = import("LrFunctionContext")
local LrLogger = import("LrLogger")

stecman

This is a technique for extracting all imported modules from a packaged Python application as .pyc files, then decompiling them. The target program needs to be run from scratch, but no debugging symbols are necessary (assuming an unmodified build of Python is being used).

This was originally performed on 64-bit Linux with a Python 3.6 target. The Python scripts have since been updated to handle pyc files for Python 2.7 - 3.9.

Theory

In Python we can leverage the fact that any module import involving a .py* file will eventually arrive as ready-to-execute Python code object at this function:

PyObject* PyEval_EvalCode(PyObject *co, PyObject *globals, PyObject *locals);

stecman

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.

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DEVICE = atmega328p
CLOCK  = 16000000
PROGRAMMER = -c arduino -P /dev/ttyUSB0 -b57600

AVRDUDE = avrdude $(PROGRAMMER) -p $(DEVICE)

SOURCES = $(shell find . -name '*.c')
OBJECTS = $(SOURCES:.c=.o)

# Automatic dependency resolution

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# Open a new kitty terminal window on MacOS
#
# 1. Copy this script into AppleScript Editor and save it somewhere
# 2. Use something like Apptivate to run the script on a global hotkey:
#    http://www.apptivateapp.com/
#
# Note this script doesn't work well as a Service through Automator as the
# "click menu" functionality requires accessibility privileges granted.
# Services run as the focused app, so that setup would require every context
# the shortcut is run from to have accessibility granted.

stecman

This is a collection of code snippets for various features on the STM8S family microcontrollers (specifically the STM8S003F3). These are written against the STM8S/A SPL headers and compiled using SDCC.

Some of this controller's functions aren't particularly intuitive to program, so I'm dumping samples for future reference here. These are based on the STM8S documentation:

• STM8003 datasheet
• STM8S reference manual

Run at 16MHz

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Automatic speaker power control from multiple audio sources

Switches mains power on for speakers while an audio signal is detected, and times out after a period of silence. Uses the AVR ATTiny13a and a couple of op-amps.

Mains switching is achieved by emulating a MS-6147-RC 433.92 MHz remote control with firmware and a simple simple on-off-keying (OOK) transmit module.

This solves two problems for me:

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Bake glyphs from fonts to image files (Python)

This is an appendix item for Unicode Input Terminal.

Protoype code to pre-render 240x240 screens, each with a glyph and codepoint metadata.

# Download Unicode metadata
wget https://unicode.org/Public/UNIDATA/UnicodeData.txt
wget https://unicode.org/Public/UNIDATA/Blocks.txt

stecman

import os

# Device definition for the stm8s.h header
# This enables available features of the device library.
STM8_DEVICE_DEFINE = "STM8S003"

# Programmer argument for stm8flash (stlink or stlinkv2)
STM8_PROGRAMMER = "stlinkv2"

# Target device argument for stm8flash