The Circadian Rave System: An Affordable, Open-Source, and Easy-to-Build System for Any Light-Based Experiments

Summary

Here we describe a protocol for building, programming, and running the Circadian Rave System, an Arduino-based light-emitting diode (LED) controller for managing multiple complex light regimes.

Abstract

Precise control of lighting has broad applications in all biological sciences, but none more so than in circadian research. Life on Earth has evolved circadian clocks that are endogenous regulators of physiology and behavior that entrain to the 24-h solar day. To study the clock, researchers rely on experimental manipulation of either light or temperature to entrain circadian rhythms. Most laboratories currently use either commercially available or in-house-built lighting equipment to either mimic or disrupt natural day and night cycling. These systems offer limited programmability and precision, lack standardization, and, in some instances, affordability. To address these issues, we have developed the Circadian Rave System, a bespoke software and hardware package that allows the precise control of multiple independent light boxes. We have made the software open source, along with detailed hardware build guides, with the aim that future research can be standardized through the use of this system. To demonstrate the functionality of this system and its utility in circadian experiments, we measured longevity and activity of Drosophila in various light paradigms to show circadian synchronization and disruption through light manipulation. In conclusion, we have developed a standardized, scalable, and affordable lighting system that can be built in-house by any researcher with minimal prior knowledge in electronics or programming.

Introduction

The precise control of light is critical in almost any experimentation involving animals. For the laboratory rearing of such animals, commercially available incubators can be purchased that have limited capacity for programming complex light and dark cycling regimes. The ability to program complex lighting regimes is necessary for many fields of study, but is critical in circadian research. The circadian clock, entrained to the solar day, is an endogenous oscillator that regulates changes in physiology and behavior from insects to mammals¹. As such, circadian research has begun to permeate many fields of biological research, such as development....

Protocol

1. Building the CRS

NOTE: The CRS was designed to be built in-house by researchers, and as such, all components are commercially available from multiple vendors (Table of Materials). The exceptions are the printed circuit boards (PCB) that must be produced commercially by PCB printing specialists or by contacting the authors. For commercial production, the Gerber files are in the GitHub repository (@Trincatalyst/CRS/Hardware/gerber/microcontroller_PCB). University engineering departments typically have PCB printing facilities. Below are detailed instructions on how to build, quality check, and program a singl....

Results

CRS overview
The CRS is a combination of hardware and software that allows users to program complex lighting regimes for up to six independent LED strips per device (Figure 1A). The software can be easily downloaded from the GitHub repository (@Trincatalyst/CRS/Software) and within the main page of the software, further detailed instructions of use can be found (Figure 1B). The hardware was designed to be affordable and easy to build by anyo.......

Discussion

To investigate how light influences physiology and behaviour, complex lighting schedules are required, typically with multiple conditions running in parallel. Precise control of the timing and intensity of light exposure is also key for reliable and reproducible data in these circadian experiments. Light cycling can be achieved with commercially available incubators or LEDs linked to mechanical timer plugs. However, these systems offer limited or no ability to program complicated light cycling parameters, and often the u.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
0.1 µF Ceramic Capacitor	Farnell	2507749	Quantity = 2
100 kΩ axial THT resistor 250 mW	Farnell	3951804	Quantity = 6
100 Ω axial THT resistor 250 mW	Farnell	3496799	Quantity = 6
1 µF Ceramic Capacitor	Farnell	2819603	Quantity = 2
2.54 mm pitch Through Hole Header Horizontal Mount - FTDI	Farnell	3756363	Quantity = 6
Arduino Headers 10 way	Farnell	1593417	Quantity = 1
Arduino Headers 3 way	Farnell	1593412	Quantity = 1
Arduino Headers 8 way	Farnell	1593416	Quantity = 1
Arduino Uno R3	Arduino	A000066	Quantity = 1
Barrel Jack	Farnell	224959	Quantity = 1
Circadian Rave System PCB	Martin Lab	Martin Lab	1 (120 strips or 1 LED component with a LED PCB)
Diode	Farnell	4245041	Quantity = 1
eFuse Circuit Protection	Farnell	4178928	Quantity = 1
FTDI Cable	Farnell	2419945	Quantity = 1
LEDs	RS	855-5933	120 strips or 1 LED component with a LED PCB
POWER SUPPLY 15W	Farnell	2815857	Quantity = 1
Screw Terminals	Farnell	2314973	Quantity = 6
ST Microelectronics N-Channel MOSFET STP30NF10	Farnell	9946403	Quantity = 6