My poor thermal imaging camera has been neglected while life went on and my time was spent elsewhere.  I even designed a thermal imaging time-lapse camera for a client was based on the ESP32.  As I worked on that project I became more disillusioned with my Pocketbeagle linux camera solution, primarily because of the long boot time for linux.  In addition the PRU pipeline would have to be reworked to support 16-bit radiometric data (it currently only supports 8-bit AGC data) and the 320x240 pixel LCD display seemed constraining.  I wanted to display a reasonable size image along with some controls.  The easiest size image to make is 320x240 because it requires a simple doubling of the Lepton's 160x120 pixel output.  However this leaves no space for controls unless they sit on top of the image.

Long story short, I ended up deciding to remake the camera using an ESP32.  To that end I designed an ESP32 development board called gCore (documented here) that uses a 480x320 pixel display and started work on a new camera design with the Esspressif ESP-IDF and LittlevGL.

The hardware is pretty simple.  A Lepton 3.5 connected to gCore via a swivel mount comprised of two simple 3D printed mounts and a screw, and a Maxim/Dallas DS3232 RTC clock with 236 bytes of SRAM for settings and parameter storage.  The RTC is powered directly from the LiPo batteries using its own ultra-low quiescent current LDO and communicates over I2C.

Firmware is a work-in progress.  At the moment the camera functionality is pretty much done.  It supports both radiometric and AGC modes.  The radiometric mode allows extraction of image temperature anywhere.  AGC can be used for higher image quality.  There's a spot meter and a bunch of palettes.  The Lepton's image can be smoothly interpolated up to 320x240 pixels.  I plan to add the ability to store images or videos on an MicroSD card.  However instead of using an image format, such as png or jpg, I will store json-formatted files with the raw radiometric and telemetry data from the Lepton and other camera meta-data.  This will allow generating images or performing thermal analysis on images later.  I also plan to add a wifi-based command interface for talking to an application for display, control and analysis of images.  I haven't figured out how to do this yet but I'd like the application to be able to further calibrate the camera for more accurate readings (Flir claims at best +/- 5C accuracy with a stock Lepton).

I haven't completely forgotten the Pocketbeagle camera.  I think I'll turn it into a web cam with a basic interface on the LCD and remote viewing through a web interface.  Not a huge amount of code I hope.