**Motivation:** Understanding ecological processes and the natural history of organisms is central to effective management or conservation strategies. Frequently these ecological processes occur across a range of temporal scales spanning hours or days to months. Collection of study data such as growth patterns, herbivory, or predation rates at daily scales is costly and logistically impossible in remote locations. For example, the cost or complexity of conducting daily surveys on coral reefs has led to a gap in our understanding of coral recruitment and post-settlement selection *in-situ*. CoralCam was developed as a low-cost alternative to commercial timelapse cameras, enabling the study of ecological processes in a wide variety of marine or terrestrial habitats. **What it is:** Each CoralCam consists of a low-cost action camera (such as a GoPro *knockoff*) which is controlled by a simple electrical circuit and easy-to-program, open-source Arduino microcontroller. A real time clock is used to improve power efficiency and the repeatability of data collection. Designs for a custom printed circuit board (PCB) are freely provided in this repository to reduce build time to approximately 1 hour or less. **How it works:** CoralCam is as much a method as it is a research tool. A real time clock wakes the Arduino microcontroller from a low-power sleep state at times specified by the user for photo or video capture. After waking, the Arduino microcontroller sends electrical pulses to two transistors which electronically "press" the Power/Mode and Shutter buttons on the camera. After data collection the Arduino powers off the camera to conserve battery life, and re-enters a low power sleep state until the next real time clock alarm is triggered. This simple approach allows detailed monitoring of remote habitats for extended periods of time (1+ months of twice-daily photos) and can be applied to a range of camera platforms. All image processing and storage is performed internally on the modified camera, reducing the need for complex programming by the end user. **How do I get one?** Just follow the included build guide. You can wire your CoralCam by hand following the wiring diagram, but we reccomend you order a few CoralCam PCB's made by a supplier of your choice and follow the included build guide. PCB's can be ordered for less than $1 USD per unit from a variety of manufacturers such as JLCPCB - just download the PCB file and upload it to the website of your chosen supplier. **Questions?** Feel free to contact Austin Greene for technical advice, questions about the build process, or potential applications of CoralCam. [1]: http://