Having identified the design parameters for the system, the next stage was to begin ordering parts and putting it together. The system was divided into three independent, functional sub-systems to make the task of assembling the system more manageable and allowing team members to focus on the sub-system that most suited their specialty. These three sub-systems were hardware, software and biological aspects.

The function of the hardware is to contain the electronics and organisms, power the LED’s/microcontroller and maximise the light available to the plants. Containment is through the use of a sealed box, with a detachable lid for access. This box is glued with tin foil and sprayed black to minimise exchange of light with the environment. Powering the LED’s proved to be more difficult, taking our engineers many days to find the optimal solution. You can find all the grizzly details on this process here. However, essentially the system is powered from a 5V 2.1A AC adapter that plugs straight in to your mains power supply. Alternatively, you can use 4 AA batteries to power the system for short periods of time if necessary. The LED’s are wired in parallel so the same light is provided along the length of the container. This can be seen from images in the Gallery.

The purpose of the software is to control the LED’s, by allowing the user to easily adapt features such as light intensity, wavelength and also specify the length of the day/night cycle. For our design, we use the Arduino UNO microcontroller to control these characteristics as it offers a user-friendly interface and is well-suited to our design. You can find all the code laid bare and a guide to the Arduino here.