Antonio Burrai
[WEEK 18]

Project development

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The weekly assignment focuses on the tracking of my progress during this six months of Fab Academy 2015, passed in developing my final project: “Piske” (fish in Sardinian dialect), un underwater robot inspired on a monkfish.

What tasks have been completed, and what tasks remain? The following tasks have been successfully completed: 3D modelling of the entire shell, design of the main control board (FabKit), design of the input and output devices (a light sensor, servos and LEDs), description of the code which makes possible the kinematic of the fish. The project involves very complex skills and features: waterproofing, underwater weight balancing, hydrodynamics, data recording and recovering and so on. This tasks will be surely the next obstacle to be overcome! An updated version of “piske” will be presented during the Maker Faire 2015 in Rome.
What has worked? what hasn't? The activities plan has worked. I’ve planned more or less all the activities (except for the unexpected) and I reach to complete my minimum prototype. The idea-to-real thing conversion has not (completely) worked because of the lot of time required to find the components and assembly all the different “worlds”: electronics must fit the shell, the shell must be easy printable, etc. Not everything could be predicted just on the screen, several debugs were needed.
What questions need to be resolved? Surely the mentioned complex skills and features (in an advanced level of design). At this stage of design the questions to be resolved are: (1) A proper clash detection of the high number of connection between the electronic parts (2) A way to fix to the shell the electronic parts (3) An even more accurate shell design (4) A proper dimensioning of the propeller shaft
What will happen when? The last week will be focused on fitting all the cable and devices inside the fish. This is the most difficult part, and several shell debug are expected. More generally, when the piske project will be complete, groups of low-cost “sensing” fishes will be free to move in oceans, lakes and ponds, directly recording a huge amount of climatic data.
What have you learned? I’m a structural engineer, used to 3d model, make stress analysis, perform clash detection and last but not least PLAN my project. My biggest effort concerned electronics, even if I’m very attracted by this topic! I’ve studied it during my university classes, but not so deeply as during the final project development. I’ve learned to understand circuits, processor, and design and realize my own boards, program it and make it works. This is in my own opinion the best part of the academy and what I’ve really learned.
Documentation during development The mentioned documentation has been fully detailed on the Final Project page.
Demand- vs supply-side time management I quickly understand not to attempt to design "the perfect fish". It’s an incredible complex problem. I take the time I had and worked backwards to determine time per task: time is never enough! So i focus on: the shell, the electronics and the code. I've talked via mail with Neil Gershenfeld and he have suggested me to read the following documentation about the ROBOTUNA project. He admitted that "How ​fish swim efficiently is a surprisingly interesting problem".
Spiral development My "minimum feature" prototype includes a complete external shell (composed on four parts), all the electronic devices (three parts) and all the cables properly positioned inside the shell, a working code which permits to the fish to swim in a safe area.
The final project slide and video have been uploaded to the archive.