DisparaTimer

DisparaTimer is a mobile app that, when connected to a Raspberry Pico W/WH, can control the exposure time of a photographic enlarger using a power relay. The physical setup is inexpensive and easy to assemble.

DisparaTimer has two operation modes. The first is a traditional timer mode, where you set a specific time for each exposure. The second is designed for creating test strips with constant fractional step increments over a base time.

On iPad (iPadOS 17 and later), DisparaTimer includes a landscape-only notes panel that lets you add photos or images of your test strips and make handwritten or visual annotations directly on them.