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tCam-Mini: An ESP32-driven Wireless Thermal Camera

Reporting from Shanghai, China
Jul 29, 2021

tCam-Mini is a small, wireless thermal camera powered by ESP32 and designed by maker Dan Julio.

tCam-Mini is a small ESP32-driven wireless thermal camera designed by Dan Julio. tCam-Mini makes getting and using radiometric data from a Flir Lepton 3.5 sensor incredibly easy. Radiometric data include the temperature of every pixel captured by the Lepton sensor, allowing all kinds of interesting thermographic analyses. Of course, that data can also be turned into the “false-color” depictions that everyone associates with thermal imaging.

tCam-Mini dev board: front & rear

tCam-Mini comes with a useful desktop application, running on Linux, Mac OS X and Windows, making the camera easy-to-use right out of the box. Custom applications running on any platform can easily communicate with tCam-Mini via a socket interface. Commands and data are transferred as easy-to-parse json strings.

Hardware Overview

  • Espressif’s ESP32-WROVER-E Module (ESP32-D0WD0V3, 8 MB PSRAM, 8 MB Flash) with built-in antenna
  • Flir Lepton 3.5 (160x120 pixel radiometric LWIR camera with shutter)
  • CP2102N-A02 USB to UART bridge with ESP32 boot loader control
  • Multi-voltage power supply (3.3V, 3.0V, 2.8V, 1.2V)
  • Dual color (Red/Green) status LED
  • Factory Wi-Fi Reset button

Capabilities

  • The tCam-Mini camera highlights the full capabilities of the Lepton sensor.
  • The camera can operate in either Radiometric/TLinear (each pixel contains temperature data) or AGC mode.
  • Simple json-based command set with the communication of a TCP/IP Socket, which simplifies interfacing with the camera from a custom application.
  • AP or STA (client) Wi-Fi modes (static or DHCP-served IPV4 address).
  • Single-image or streaming-data modes.
  • Control over sensor emissivity, gain and spot-meter location.

The companion desktop application makes it easy to use the camera and analyze data from it.

  • Displays images or streams with multiple palettes.
  • Saves and loads images or streams in files preserving the radiometric data for use later or by other applications. Two file formats: image and video (described in the Github repository).
  • Exports images as jpg, png or tiff files.
  • Copies current image to the computer’s clipboard.
  • Histogram display and analysis of pixel populations.
  • Spot-meter and up to four additional markers showing temperature at various points in an image.
  • Graphing function to plot spot-meter and marker data over time.
  • Graph baseline mode to allow comparing temperatures to a reference point in the scene (for example to compare a temperature to a blackbody constant).
  • Exports graph data in a text file for analysis by other programs.
  • Prints graph (or creates a PDF on computers that can saved as PDF).

Open-Source

The hardware and firmware design files are available in Dan Julio’s Github repository. The firmware is designed to be compiled using ESP-IDF tools, and new code can be loaded via the built-in USB Serial port.  Precompiled binary files are also provided for easy upgrades. Development is ongoing with new features and additional software support planned for a Python library and web server.

To get all the details about tCam-Mini, you can check out the Dan Julio’s campaign webpage.

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