CDR

After testing the different sensors, the Raspberry Pi connection via USB, the Light Module and more we are finishing the electrical design... Atleast for now ;)

The first Mainboard prototype has shown, that even with few components the routing of the wires can be pretty annoying. Thats why we switch to a four-layer PCB design. The front contains most of the components: The Raspberry Pi Zweo 2W, a CO2 and a O2 sensor, a environmental sensor that can measure humidity, pressure and temperature and an additional mixed-signal processor (MSP), a MSP430 from Texas Instruments. The camera is placed behind the

Besides the light the Mainboard is another central component of our experiment. It contains the used Raspberry Pi Zero 2W and hosts most of our sensors. Another purpose is the connection of the CubeLab electrical interface with our components.

To be able to download images during the experiment is running, a USB connection to the SpaceTange SpaceLab will be established. Therefore the USB signals need to be routed through the CubeLab Interface over the Mainboard to the Raspberry Pi. Latter normally interfaces outher electronic parts over a 40 pin header row. In this case the USB connection needs to be

Humidity tests with fan

Today we tested whether the fan can sustain a high humidity in our experiment. Due to the agar and the plants the relative humidity inside our experiment can exceed 100% so that condensing water occurs. This can be bad for electronical components in general so we have to find a solution for this problem!

For this test, we first sealed the fan with a hot glue gun. Then we poured some hot water inside a box and placed our fan in it on a small platform. The fan was running at full power! We closed the

Rootcutting

In the past experiments we had some nodules but not enough to do serious experiments on them. To identify if we can get more nodules by cutting away the tip of the roots at different stages, we sat up another preliminary experiment.

The experimental design shows the different treatments. Uncut plants and plates are used as a control, to see if there is a difference and where the difference comes from.

Then we had to prepare the seeds and the agar again.

This time i shooted a picture of the autoclav, too. It is used to desinfect all the

There will be light

Today the first batch of prototype pcb for the light module arrived. They are designed to only need one side to allow additional heat removal on the backside. As the components already arrived last week we where able to assemble our first light module.

In contrast to out plant box prototype pcb we increased the number of LEDs to 15 to allow a more even light distribution. To drive the LEDs to methods are implemented:

• On the one hand the current running through the LEDs is achieved by a simple series resistance. To control the brightness an additonal N-MOSFET is

Our plant boxes have been in use for a while and show first results: First of all they look pretty cool in the dark.

But we also learned that the correct choice of material and manufacturing process is important. The simple FDM printed boxes using PLA as material are not tight enough. Also sterilization cloud not be performed as it would have been necessary: In the end mold started to grow and we had to dispose the containers. The problem is, that those simple boxes cannot withstand the hot autoclavation process and had to be sterilized using alcohol wet-wipes. The