# Low-cost, open-source device for simultaneously subjecting rodents to different circadian cycles of light, food, and temperature

## TL;DR

This paper presents an affordable, open-source device to control light, food, and temperature cycles for rodents, enabling simultaneous circadian research without disrupting lab conditions.

## Contribution

A low-cost, open-source device that simultaneously controls light, food, and temperature for rodent circadian studies.

## Key findings

- The device successfully controls air renewal, illumination, temperature, and cycles for rodents.
- Bench testing confirmed stable and realistic environmental conditions for circadian experiments.
- The total cost of the device is under $300, making it accessible for widespread use.

## Abstract

Exposure of experimental rodents to controlled cycles of light, food, and temperature is important when investigating alterations in circadian cycles that profoundly influence health and disease. However, applying such stimuli simultaneously is difficult in practice. We aimed to design, build, test, and open-source describe a simple device that subjects a conventional mouse cage to independent cycles of physiologically relevant environmental variables. The device is based on a box enclosing the rodent cage to modify the light, feeding, and temperature environments. The device provides temperature-controlled air conditioning (heating or cooling) by a Peltier module and includes programmable feeding and illumination. All functions are set by a user-friendly front panel for independent cycle programming. Bench testing with a model simulating the CO2 production of mice in the cage showed: a) suitable air renewal (by measuring actual ambient CO2), b) controlled realistic illumination at the mouse enclosure (measured by a photometer), c) stable temperature control, and d) correct cycling of light, feeding, and temperature. The cost of all the supplies (retail purchased by e-commerce) was <300 US$. Detailed technical information is open-source provided, allowing for any user to reliably reproduce or modify the device. This approach can considerably facilitate circadian research since using one of the described low-cost devices for any mouse group with a given light-food-temperature paradigm allows for all the experiments to be performed simultaneously, thereby requiring no changes in the light/temperature of a general-use laboratory.