<h3>Introduction</h3>
Microalgae are grown for the research on photosynthesis, biotechnology, and water-environment ecology. Specialized laboratories typically use calibrated commercial equipment, which agitates the microalgal culture by shaking or bubbling, controls the irradiance, temperature, and CO<sub>2</sub> content. Such commercial incubators may be out of reach for some laboratories, like those not specializing in microalgal research, teaching laboratories, or laboratories in low resource settings. Our research uses microalgal cultures during the development and validation of advanced microscopy and flow cytometry techniques. We lacked access to and the budget for a commercial incubator. We solved the problem by building a stand-alone orbital shaking incubator with an in-built variable light source on a 24-hour timer. The shaker features a homogeneously illuminated growth area of 20 cm × 15 cm, which is suitable for three T75 tissue culture flasks or six 100 ml Erlenmeyer flasks. The overall material cost was around £300 and assembly time of about two days. We tested the shaker with fresh-water microalgae *Desmodesmus quadricauda* and *Chlorella vulgaris*. Both microalgae cultures have been grown continuously for seven months in the incubator. We studied their growth under different light conditions to validate the function of the shaker. The protocol outlines the step-by-step process to the building of this microalgal incubator.
<h3>Data Repositories</h3>
The documentation is centered around <a href="https://app.labstep.com/sharelink/221d4460-8591-4ab5-ac0c-70b54c93532a">Labstep electronic labbook</a> project.
The electronics circuit has been designed in <a href="https://kicad-pcb.org/">KiCAD</a> and the design files are available in a <a href="https://github.com/jnedbal/LEDregulator/">GitHub LED regulator</a> repository.
The 3D CAD files for the custom case for the electronics are part of an <a href="https://cad.onshape.com/documents/fb13b048a8878b03f7240f7f/w/1c6fbf6ba334d21069dd6081/e/d014bfed5ec35242676d7c45">Onshape LED regulator case</a> project.
The 2D CAD files for cutting the orbital shaker secondary platform from clear acrylic is in an <a href="https://cad.onshape.com/documents/6e8168125917f536e49b97f0/w/850d8af207ac1bb7fb7fb177/e/c75d655e7df171cc2cb773bf">Onshape Orbital shaker platform</a> project.
The raw data and the <a href="https://www.mathworks.com/">Matlab</a> code for analysis and display of results from microalgal culture proliferation experiments are in a <a href="https://github.com/jnedbal/growthCurves">Growth curves</a> repository.
The above repositories will always contain the latest versions of files and protocols. This OSF project will contain a snapshot of the above repositories for the purpose of publication. Use this repository to obtain exactly the data and files used in the associated publication. Refer to the original repositories for the latest changes and updates.
