Alternate tCam-Mini firmware with composite video out

[Dan Julio]

I recently found this awesome monochrome composite video library for ESP32 on github.  It uses the built in I2S and DAC peripherals to create the analog output on one of the GPIO pins.  I thought it might be kind of cool to see if I could make tCam-Mini output analog video so I mashed up some of the original tCam-Mini code with this library to make firmware called tCamMiniAnalog.   It works pretty well.  I'm running the Lepton 3.5/3.1R in AGC mode to get the best image quality and using linear interpolation to scale it up to 320x240 pixels.  I get the spot meter temp from telemetry and calculate the min/max points and can display all three plus the temp overlayed on top of the image.  Of course since the output is monochrome there can only be two palettes: white-hot and black-hot. And finally the firmware lets you set the emissivity and format of the temperature units (°C or °F).  Although designed to run on tCam-Mini Rev 4 boards it can also run on a home-made tCam-Mini as long as you use a ESP32 WROVER module (for the PSRAM) and a Group Gets Lepton breakout board.  Lepton 3.0, 3.5 and 3.1R are supported.  Documentation, code and instructions can be found at a new repo here.