A darkroom photographer built his own f-stop timer by wiring an iPhone app to a $20 smart plug.
The tool, called Darkplug, pairs an iPhone app with a cheap smart plug that flips an enlarger on and off over the local network. It covers the core features of commercial f-stop timers: standard and f-stop timing, test strips, a dodge-and-burn workflow, split-grade printing with two timing channels, and paper development timing. The developer, who prints film in a converted bathroom darkroom, has been using it for several months. He built the app with Codex and Xcode, and says outright that it was "vibe coded" rather than carefully engineered.
Dedicated f-stop timers from darkroom suppliers can run into the hundreds of dollars, a real barrier for anyone experimenting with film printing on a budget. This project shows that a phone most people already own, combined with ordinary smart-home hardware, can match that functionality for the price of a fast-food meal. It is also a small, concrete example of AI coding tools letting hobbyists build niche software that nobody was ever going to make commercially.
Whether a vibe-coded app survives contact with actual darkroom chemicals is the photographer's problem, not ours. But at $20, it is a cheap way to find out.