I initially had several different ideas I was thinking about making. The decision finally came down to thinking about something I might actually use and that I would be EXCITED about making. So, I settled on an animal habitat. My daughter and I have been animal lovers for years, going to exotic animal shows and owning a variety of what most people would consider "weird" animals. However, as a science teacher, I know that environment and conservation issues affect ALL animals, not just the cuddly ones. I did look around the FabAcademy archives and didn't find anything really related to my project except some hydroponics type projects. However, I don't consider myself to be "starting from scratch" as there are many many different types of animal habitats out there. I am basically custom building one for a specific species of reptile (leopard gecko or similar) and adding environmental response electronic parts. I am planning on using an ambient light sensor that turns on some LEDs, but I think this will serve as a proof of concept for turning on an infrared heat lamp when it gets dark, or using a temperature sensor and turning on a heating pad, etc, in response to temperature changes.
During Week 17, I created a Google Sheets document outlining my materials. Not all of these were purchased, some were already in our FabLab inventory, so I am breaking these down into what I actually purchased vs what I used from the lab. Additonally, some items were purchased and shared among the multiple FabAcademy teammates who were working in our lab.
I used plywood, molding and casting materials, a single sided copper board for milling my PCB, surface mount soldering parts like resistors, capacitors, LEDs, an ATMega328a chip, header pins, and crystal, PLA for 3D printing, and vinyl sticker material.
A rought estimate for the cost of this will be around $250, which is pretty steep, but comparable to a plain tank that you would find at a pet shop or reptile show. The bulk of the cost comes from the acrylic. If that cost could be reduced in some way (maybe a thinner acrylic?) then the total cost could come down significantly.
There have definitely been issues as I've gone through this process. I had to redo the wooden base design. Additionally, when redesigning/modifying my Satshakit board, I ran a design rules check and I had an airwire error in Eagle that took me a few minutes and some google searching to clear up. Also, I realized pretty quickly that the acrylic I chose was too thick. I should have gone with 1/8" instead of 1/4", which was way too thick and especially too heavy! Also, it cost more, so switching to 1/8" acrylic will bring the cost down quite a bit.