Problem solving and repetition - those were the themes these last couple of weeks.
We have been making great progress on the lantern! The wire structure is finally complete, with leaves, branches, and detail texture (bumps), Additionally, before adding more lights, we tried to drive the lights using data directly from the garden! In the first picture above, the brightness of the lights were relative to the light amount in the garden and the amount of green lights on came from the moisture level.
My mother was also in town this last week (picture 2-3) and luckily she wanted to help solder tons of lights! We already had 90 lights in the lantern when we began and by the end there were ~230 lights. So my mom was busy! We even set up two soldering stations at home so we could work there! All the work paid off today as we were able to get all parts of the lantern contain lights.
However, the lights presented a few challenges. Due to the large number of lights, when I first soldered them all together (~150 lights) we started to see dimming of the lights in the last third or so of the strand. After running some tests we decided this was a power issue and that making the strands shorter and driving multiple strands would be useful. However the Raspberry Pi could only drive one strand of lights (only one PWM pin) and so Jiffer (postdoc in our lab) helped me set up an Arduino Uno to control multiple strands. However after setting this up we realized there was still a power issue due to what seems to be resistance in the thin wire used to connect all of the LEDs (rainbow wire was used). We found this because when setting the strand to show all white LEDs, 3/4 of the strand end up being pink or red (final picture shown).
Therefore, the next step will be to connect parallel power to different points in the strand to help fix this issue. Once the lights are complete and giving a whole range of colors then I can begin papering the lantern and moving it to it's new home, which is the lobby of the ATLAS (our) building.
Plants are still growing strong! The little plants (lettuce, tomatoes, and mint) are getting ready to be moved to the third level of the garden as they are not so little any more. However, we are working out some kinks in the gardening process. We had two leaking episodes in the last few weeks. The first time we could not find a source and the second time (just on Tuesday) we at least narrowed it to the large water storage container on the left. Both seem to have occurred when the container got refilled, so perhaps it is just overflowing after being refilled. We will keep working to identify if this is indeed the issue.
We are now beginning to collect data regularly from the garden in a few different formats. Every hour we take a picture of the garden using a webcam. Currently we are imaging the second level (picture 2 above), but because the first level plants are younger we may move the camera there to get a time lapse of the growth. We are also collecting temperature, humidity, soil moisture, water presence in the tub and light data. These data are collected using sensors in level two using Willow (the BlockyTalky). Willow sends an OSC message to a machine in which we are storing all the data in a csv file so that we can have a the historical data for the garden. We are working out the bugs to get Willow to constantly send data to be stored for access later. Finally, we are also collecting hand measurements; height, width, leaf number, and general health by looking. We began by measuring the plants 4x a week but decided that was too often so have decided on 1x per week.
Overall, though the last few weeks have presented it's fair share of challenges, we are starting to see the benefits of all our hard work! It has been really fun to see the garden progressing and now it is very exciting to see the lantern all lit up. I'll try to add a video of the lights in the next blog post and maybe a time lapse of the garden!