Posts by William

Total: 8 posts.

Replacing GBA cartridge battery

Recently, I wanted to test a Pok√©mon Ruby cartridge I’ve had lying around for a while. It had quite a lot of playtime on it, so I was keen to see if the save data was still intact. After powering on the GBA, I was greeted with an unfortunate, but somewhat expected,

LED controller PCBs arrived

The PCBs I designed for a simple LED controller just arrived. They were manufactured by Seeed Studio. The controller has a single FET to set the brightness of a connected LED strip using Pulse-Width Modulation. The PWM signal is generated by a PIC microcontroller and can be adjusted with a single piezo

Grf extractor

Grf extractor

I made this tool in 2002 to extract the Grf resource files of the game Ragnarok Online (alpha version). I reverse engineered the file format by analyzing the files with a hex-editor and guessing the compression used. The files turned out to be compressed with a variant of the LZ-compression algorithm. The

RFID emulator

RFID emulator

The underground waste containers in my neighborhood used to have an access system based on Texas Instruments’ TIRIS RFID tags. The tags contain a 64-bit read-only identifier that is read using a low-frequency (LF) electromagnetic field of around 134 kHz. Data bits are modulated using Frequency Shift Keying (FSK). Since the system

Infrared remote top

Mini infrared remote

I had some space left on a panelized PCB I wanted to etch, so I decided to fill the remaining space with a small project I had in mind. The idea was to make a small infrared transmitter, controlled by a PIC microcontroller, that could run off a single lithium cell (CR2032).