Obtaining funding for parts, for me, is the hardest part of any build. I teach at a Title I school where 86% of students qualify for free or reduced lunch. To accomplish this task I usually turn to the following sources: the trash, Donor's Choose, or writing grants.
Donor's Choose is a great place to fund a project. I recommend to keep projects below $500, so they can be funded faster. Sometimes I will break a Donor's Choose into multiple fundraisers over time to make a high priced project more easily fundable. I created a Donor's Choose for 3D Printers, as a future extension for the camera trap project so students can design and print a camera trap case.
Grant writing is how I funded this project. Grants are the act of asking businesses for funding through written letters or applications. Thanks to Best Buy North America, we were able to gain access to Raspberry Pi 3 units. Many companies have trouble finding enough applicants to fully spend the allotted amount of money they attribute towards their grant opportunities. A simple Google search for grants in the area of your project goes a long way.
My main point: please exhaust all your options before spending personal money. All together this project costs about $100 per trap.
Raspberry Pi is the main ingredient for the project. The cost of the board is $35 and can be purchased at many places. I received mine through the Kano Kits that Best Buy donated, but have also purchased the chips through Amazon. You can also buy starter packs that includes the charger, microSD, HDMI cords, and a case for around $50-$60. Before spending on the whole kit, I recommend using a micro-usb phone charger lying around the house, and purchasing a cheap microSD card, at least 8gb in size.
A Picam. I learned the hard way on this one, the cheap comes out expensive. Please do yourself a favor and buy the officially licensed Picam. I purchased mine for $25 a camera on Amazon. I have also seen them at Micro Center for the same price. I initially bought 13 cheaper cameras at half the cost, but out of the 13, only 6 were functional after the first day.
Passive infrared sensors (PIR) are needed if you plan on building a motion activated camera trap. These are cheap, usually costing around $5-$8 for packs of 5. You can find them on Amazon, but Adafruit has a great tutorial of how they work, and how to adjust the sensitive and time delay. This Adafruit article really helped my students understand the how-to more in depth.
Three female to female jumper cables per trap are needed if you plan on building a motion activated camera trap. The ones on Amazon come in packs of 120, so one box covered the 12 traps my students built. These are needed to connect the PIR to the GPIO pins on the Raspberry Pi board. You can find these at almost any electronics store.
A strong power source is key to running the Raspberry Pi for a sufficient amount of time for data gathering. What I have found is 1,000mah = 1 hour of run time. Spell Foundry has a great calculator to help you with calculating run times on a charge, but it is a fun exercise to have students calculate their camera's run times during the testing phase of the project. I fully recommend the ExpertPower 20,000mah battery pack, this thing holds a charge through rain or shine and provides 20 to 24 hours of run time per charge at around $17 per pack.
Large photo and craft keeper from Michaels (unfortunately no link, so I took a picture). Originally $40, I used a 40% Michaels coupon to bring down the cost to $24. These are the water proof-cases for the camera traps, and work fantastic! If not possible to purchase, some kind of plastic case that encloses the Raspberry Pi and keeps the water out.
Other components include a drill, X-Acto knife, hot glue gun, and at least one 8GB microSD card per trap.
This is an investment for a big project. Please feel free to email me if you have any questions, or leave a comment below. Part III, the coding will be posted tomorrow...