“A 3-D printable open source platform for fluorescence microscopy, optogenetics and accurate temperature control. Designed for flexibiliy and low-cost, the FlyPi is an optical microscope designed for behavioural work with fruit flies, zebrafish or C. elegans. The system is based on a Raspberry Pi with camera, an Arduino microcontroller and a range of off-the-shelf electronic parts. A modular design provides for flexible control of a range of peripherals including options for optogenetic and thermogenetic stimulation and fluorescence microscopy. All mechanical parts are 3-D printed which includes a range of manual or motorised micropositioning options.”