I'd like to take some time to reflect on what I encountered with this project. I will start with the Trinket Pro side of things then move on to Android.

Hardware (Trinket Pro and components)

Trinket Pro

1. Awesome little controller. I will gladly use 2 pins for a USB bootloader. I look forward to using this in further projects
2. I wish the bootloader didn't wait as long to start the FW or if the bootloader would only start on hardware reset

1. Awesome resolution
2. Can require a bunch of RAM (depending on the Library)
   1. functions can be stripped to gain back ram
3. Would opt for a bigger (same resolution) next time 1.3 inch or so

1. Very nice not to have to do in code.
2. Bulky hardware
3. Timing sensitive (but can be fixed)

1. Awesome to have all of this built in.
2. A bit expensive to buy all of the breakout boards
3. Plan on making an all in one at a later date

1. I Love this little module. A bit overkill. yes. but easy to work with
2. Replaceable for a 4 pin UART based module (3.3v)

1. I always underestimate how long hardware takes me. It took a good few days to get everything in the Altoids tin and working.

Software - Android

Android is a lot more time consuming than I remember. I always run it to odd issues. My saving grace for this project when it comes to android is that I was able to reuse the BluetoothSerialService (slightly modified). I remember this taking days to get right. There are still a ton of things I want to learn about android application development and the resources are out there. Hopefully I will have more time in the future to look into this more.

Future Improvements

I want to make the device more state-ful with various additional menus and a bunch of additional functionality. This has been a fun learning exercise. I was able to cram quite a bit into the Trinket Pro firmware and still have a lot of ram (despite the OLED Libs) and code store space left.

I would also like to make a PCB for inside of the altoids tin to make it look better. I may do this as a Rev 2. It sounds like a fun design project. I would integrated the Trinket Pro ref design and the lipo management and a handful of other components on the same board. Would free up space in the tin.. Say to carry headphones or something.