My original long-term goal was to create a capable thermal imaging camera using the Beaglebone Black and a 7" LCD cape as the platform matching some of the features of high end commercial products. However it soon became obvious that I'd need a simpler platform to learn how to use the Lepton module when I started reading the documentation and playing with the various demo codebases. It is a very capable device with a moderately complex interface, both firmware and hardware. Although the device has good default settings I found enabling some features wasn't well documented and the video SPI interface (VoSPI) challenging to implement due to its real-time constraints.
There are a lot of other great projects online to help get going with the FLIR sensors. Pure Engineering is to be commended for making these devices available to makers and provides a wealth of code examples, many designed to work with the previous Lepton models. Max Ritter's DIY Thermocam is probably the most mature and well known. He has done a great job and I pored over his code. Damien Walsh's Leptonic is also really well done and works with the Lepton 3.5 as well. Both Max and Damien were very gracious when I sent them various questions.
I decided to follow Max's lead and build a test platform using a Teensy 3.5 that I had (selected for the multiple SPI interfaces and copious RAM). Unfortunately after soldering the Teensy to a Sparkfun breakout board I stressed the processor BGA package and made the board unreliable. So I replaced it with a Teensy 3.2 hoping it would have enough resources to successfully interface to the Lepton. It does, barely, and the next project log describes the test platform hardware.