Alrighty... Got some updates here. Finally got the flat head screws and I recut the upper plate. I do woodworking, not metal working, so I'm using a bandsaw to make long straight cuts. Because I don't have the right jig or more probably the saw itself, the cuts are not very straight. I've tried building a couple jigs but I really need a full metal jig or a metal miter bandsaw. Idk. I've got plenty of stock and this ain't that big a deal, so we'll see.
I'm not going to attach the bottom plate, because I think I like the access to the ports. If I can secure it firmly enough, that is.
It's also tighter than I surmised to fit the battery and the pi. I'm thinking about using a 4000mA cellphone battery which is flatter and hopefully fit better. I found a guy on Instructables who did this with a pi 2 and a 1500mA (I think).
Finally, with long diliberation with my son and a few friends, and of course you... Here's the list:
GPS Hat https://www.adafruit.com/product/2324 (if it will fit) - it seems this would be a basic feature of any landing party. I mean without coordinates, how would we know where to land?
Ultrasonic distance sensor
https://www.adafruit.com/product/172 - This is only good up to almost 20 feet... But oh well, short range sensors it is.
https://www.adafruit.com/product/2652 - I like that these three are in one sensor. The more the better.
So, those are the three that will use the 3 buttons on the panel.
As for the hand held device;
Gas sensor (hand held)
https://www.adafruit.com/product/3199 - this gas sensor can detect several gases, however, as the description states, "This sensor is sensitive to CO ( ~ 1 to 1000 ppm), Ammonia (~ 1 to 500 ppm), Ethanol (~ 10 to 500 ppm), H2 (~ 1 - 1000 ppm), and Methane / Propane / Iso-Butane (~ 1,000++ ppm). However, it can't tell you which gas it has detected.
Would be nice if there were some software update that would allow for differentiation, but something tells me it's hardware.
That's it for now... Keep y'all posted!