This week, I helped the team do more tests in order to see if we could replicate the results we found last week regarding our solution of the swinging problem. We also finalized our choice of cameras after some range tests off the bridge, and began designing our final housing.
For the drop tests, we first lowered the total added weight through rocks to exactly 1 pound (it was 600g before, whereas ~450g/1lb is the actual weight of our payload). We also charged the battery fully and ran additional thrust tests using the scale. We found that at 100% power using 16 AWG wure, we were getting almost 700g of thrust, a marked improvement over previous week’s results.
For the actual drops, as usual, I held up the device by the parachutes as Lahari initiated the device. We first ran with 50% power to the motors and noticed a very minute movement. We then decided to change this to 75% and dropped an additional two times, noticing noticeable levels of movement in the direction of the motors. I also took pictures from the bridge looking down to document where the device landed, so we could compare to the no motor drop.
To try alternative cameras, I ordered an 120 degree camera from the ECE parts inventory to see if the smaller FOV would make the circle easier to detect. I tried setting it up with the Pi only to find that the one we had was for the Nvidia Jetson, so the Firmware was not compatible. I then helped Lahari and Vikram modify existing scripts we had in order to support a USB webcam (as the exiting PiCamera module only supported the CSI Pi Camera module). This involved modifying the code to use the generic OpenCV camera access functions, rather than PiCamera specific methods. After this was done, we went out to test this new webcam against the old 160 degree FOV camera.
We came up with a quick testing strategy where I would hold the device over the bridge, say the testing parameters out loud (resolution + camera type + lateral distance from target), and Lahari would record the screen and mic feed using OBS. Using a tape measure, I measured up to 4 meters away from the location of the target, with increments of 1 meter such that we measure the performance of each camera at each resolution at each distance away from the target center. Lahari and I started with the 160 FOV fish eye camera and noticed that it was not even picking up the target on the ground, even after we doubled its diameter to 2 meters (the fish eye effect made everything in the center of the frame super small). We decided to call of the further tests with the fisheye, and moved onto the Webcam. With the Webcam, the target was large and clear in the frame, and we were able to proceed with the entire suite of tests. (640 x 480 vs 1280 x 720, at 1, 2, 3 and 4 meters away from the center of the target).
Lastly, we brainstormed ideas together for a final housing. As we ended up choosing acrylic, Lahari and I worked together to quickly create DXF files for the hexagonal base of the device, as well as the rectangular side walls using Solidworks. Our next phase is to fully construct this housing, and test the device with the full camera to propulsion piepline.