GBCMR - Game Boy Camera Meets TRMNL

Visit GBCMR :: Demo gallery

The Game Boy Camera is a perfect match for TRMNL. They’re both personal, minimal, and - most importantly - 2-bit grayscale.

That’s why I created GBCMR. It fulfills a few goals:

1. Offload photos directly from Game Boy Camera with GBxCart RW
2. Create and share photo galleries with your friends
3. Stream that gallery to TRMNL e-ink displays

Photo Download and Conversion

This is pure JavaScript in the browser. It requires WebSerial support. Chrome, Edge, or related browsers are supported, but not Firefox or Safari.

The GBxCart driver was based off FlashGBX’s Python implementation.

The album of 30 photos is stored in SRAM, beginning at address 0x2000 and incrementing by 0x1000 for each subsequent image. The image format is optimally packed - each pixel takes up exactly two bytes. That’s (128 width * 112 height * 2 bits) = 28,672 bits per photo, or 3,584 bytes.

Jimp is used to draw the image, which is converted to a proper 2-bit grayscale PNG before saving to disk, reducing the file size by a third (compared to the default 8-bit RGBA). The resulting PNGs are even smaller than the 3.5 KB raw images due to PNG’s lossless compression, typically coming in around 1.5 - 2 KB.

Photo Galleries

There’s no need for a fully-fledged account system, so it’s “security through obscurity” here. Each gallery gets unique public and private URLs. The private URL permits uploading and removing images, and the public URL is read-only.

TRMNL Integration

The public URL also exposes a couple endpoints for images to be directly displayed on a TRMNL e-ink device. The photos are resized with integer scaling so that they remain pixel-perfect.

Simply use the URL generator built into GBCMR and copy the URL into the TRMNL’s Alias plugin. A new photo will be shown every time - no need to refresh any data on TRMNL’s side.