In my last post about the lantern I was working on getting enough voltage to all my lights by running parallel power lines. After having a failed attempt at this using only thin ribbon wire for extra power lines (not ground), Jiffer recommended using thicker speaker wire and running parallel power and ground lines. This was the key! You can see the progression from last week's dimming issue (white turns to yellow), to this week's full white lights!
It took 14 parallel power lines to achieve this wonderful white light. This was a mess to say the least! So to make this a bit more organized I soldered the power lines to a perfboard, leaving only the signal lines (and one ground) to be connected directly to the Arduino Uno and getting rid of the mess of alligator clips.
Since the lights were up and running I could start testing out the paper on different areas of the lights (such as the bumps on the tree extremities) to make sure it was bright enough and to try out some paint and wax combinations. I still deciding between black and white paint/wax or adding in color, especially when planning to use the full RGB spectrum of lights.
And of course after some test runs I finally started papering the lantern! Here is the progression from today! Hopefully next time I will be able to get a time lapse of the papering process.
Though some plants are doing better then others we can now watch this in action (almost)! Here is a time lapse of the last month of one level of the garden with images taken every hour. The flashing occurs as the lights on a timer go on/off throughout the day/night.
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!
Lantern making finally started! The Creative++ jam was a great opportunity to get some long hours of work done on this large scale lantern - and it took a whole team of us to make as much progress as we did over just two days! Following instructions from a master lantern maker (my sister) I built a wooden frame to support the wire structure first due to the large size (~9ft tall). Once the wooden frame was constructed, the outline of the tree was shaped using 12 gauge wire and tacked, using circles of the wire, to the wooden frame. Then the details began; these were added using 14 gauge wire that is more flexible for intricate details like the face. All the wire is attached using string and glue. Once the base of the lantern was formed we were ready to add the lights inside!
Work on the lights began before the creative tech jam. Ben and Kayla DesPortes (visiting PhD student from Georgia Tech) worked to find a way for the individually programmable LED strip to communicate with BlockyTalky. Then we connected that to the data from the garden with a basic program that controlled how far the green lights went based on moisture levels and the brightness controlled by light levels. After figuring out the communication, it was then time to cut apart all the LEDs on the strip and solder them back together so they could be spread apart inside the lantern. However, this was quite a daunting task that required many helping hands! By the end of Creative++ we were able to attach the whole string of newly soldered lights to the lantern (video to come!).
A lot has changed over the last few months with the garden.
After building a large wooden structure to hold three levels of hydroponics, we started a single layer to test out water flow in our ebb-and-flow system. We started with coleus, basil, thyme, lavender, and marigolds (picture 1).
After a few weeks the plants were huge (picture 2)!
This last week we had to remove the coleus from the hydroponic system and transplant them to new pots as they were taking over all the space of the other plants (picture 3). The basil had also grown a ton and we harvested about 3-4 cups. We made some wonderful caprese with the basil - yum!
We then planted some more plants which have since sprouted (picture 4).
These are tomatoes, lettuce, and mint (which just sprouted today).
We also set up a second level of the hydroponic garden (picture 5) which has seedlings from our second round of plantings that include more basil, thyme, and lavender.
Finally, we have also added a few more sensors to the garden; now we are measuring temperature, humidity, light, water presence, and soil moisture using a BlockyTalky named Willow (picture 6).