What this is

Unit 5D is the photo wall for our apartment. There's a cork board on the wall at home and a small photo printer next to it. Anyone with the link can open this site on their phone, take a photo, and it prints: a real 4x6 card that comes out of the printer a minute later, ready to pin up. The same card goes on the online board, so the wall at home and the wall here always match.

There's no upload button on purpose. Every photo has to be taken right here, in the moment, the way you'd use a disposable camera at a party. No camera roll, no filters to pick, no retakes of a photo from last year.

How to use it

• Tap Take a photo. Your browser asks to use the camera the first time.
• Switch between the front and back camera, or turn on the 3 second timer for group shots.
• Pick a style at the top: Polaroid (the default, a white frame with room to write) or Full, where the photo fills the whole card edge to edge. You can switch after the shot too.
• On a Polaroid you can write something after the shot. It goes in the white space under the photo, in a marker font, like writing on a Polaroid with a Sharpie. Leave it blank if you like.
• Tap Pin & print. The photo goes on the board and into the print queue. Each card says whether it's waiting, printing or done.

How the prints look

Every card is laid out like an instant photo: a white frame, a 4:5 photo, and a deep bottom margin. The photo gets the look of a disposable camera: a cheap plastic lens that's sharp in the middle and soft and dark toward the corners, fine film grain, and faded, warm colour and the date burned into the corner in orange seven-segment digits, the way 90s point-and-shoot cameras stamped '26 10 23 onto the film. The stamp uses Denver time, and it's drawn on the site itself rather than with a font, so the viewfinder preview and the print match exactly.

The printer

Prints come from a Canon SELPHY CP1500, a compact dye-sublimation printer. Dye-sub prints are smooth continuous-tone photos (no ink dots) with a clear coat over the top, so they hold up on a wall. The printer sits on the apartment Wi-Fi and a Raspberry Pi drives it. The Pi runs a small print agent that asks this site for the next photo in the queue and sends it to the printer through CUPS, using the printer's built-in AirPrint support, so no special driver is needed. While the printer is off or out of paper, photos wait their turn and print when it's back.

Limits

Since anyone with the link can print, there are a few limits to keep the paper supply sane: one photo every 15 seconds and 15 a day from each phone, and 40 prints a day in total. After that, new photos still go on the online board, they just don't print.

Privacy

Photos on the board can be seen by anyone who visits, so only take photos people are happy to have pinned up. There are no accounts and nothing to sign up for. The site doesn't keep your IP address beyond the rate limits above, which live in memory and reset each day. Photos aren't offered to search engines.