While the light boxes we build are far from technical mastery, they are easy to use and fulfil their function while looking great. As the design uses a minimal amount of parts, it is very easy to build by inexperienced teams and can be greatly augmented if needed. Therefore the spirit of the modular approach of the iGEM competition is extended to the lab equipment as well.

In the most basic version, a single high-power LED will be powered by a constant current power supply. We used these, as the input voltage can vary between 100-240 V AC. This should be sufficient for most countries. At this point the LED can be turned on/off by an usual switch. We used this connection cable with an integrated switch for this purpose. Our current wiring setup:

image/svg+xmlPower supply CC supply LED

The next step would be to add dimming functionality to the setup. We achieved this using PWM dimming. For a single LED or a series of LEDs that have to glow at the same intensity this can be done using this controller. image/svg+xmlPower supply CC supply PWM dimmer LED

Since our own construct needs blue, red and far-red light sources that can be controlled individually, we needed four PWM dimmers. In order for costs to stay low we used an old ATX power supply as the primary power source. Since dimming and constant current supply we still needed we used a CC step-down buck converter, like this one, that could be controlled by PWM. We controlled the buck converters with an Arduino Uno unit, as this allowed for running set programs of illumination duration and intensity. The green LED was used as a working light, as our light-switches are not excited by green light.

image/svg+xmlATXpower supply CC supply LED PWM CC supply PWM CC supply PWM CC supply PWM Arduino PWM OUT ACpower LED LED LED PWM IN

One of our collaborations consisted of building a light box for iGEM Aachen using a high-power UV LED in order to cleave of a protection group that inactives the activity of a protease. In order to give them even further options regarding intensity control we build their box with a height-adjustable plate holding the LED. Therefore very high light intensities can be accomplished. Here you can see us presenting them the box on our visit to their lab as well as a few pictures of the box before we modified it for them.