Get current temperature of IR-Camera

[Machriam]

• The Flir Lepton 3.5 measures temperature in two places:
  • at the shutter for calibration
  • in the camera itself for overheat detection
• The following code in python retrieves temperature data:

  
  from ctypes import *
  libuvc = cdll.LoadLibrary("/srv/leptonPrograms/libuvc.so")

AGC_UNIT_ID = 3 OEM_UNIT_ID = 4 RAD_UNIT_ID = 5 SYS_UNIT_ID = 6 VID_UNIT_ID = 7

def call_extension_unit(devh, unit, control, data, size): return libuvc.uvc_get_ctrl(devh, unit, control, data, size, 0x81)

See https://github.com/groupgets/purethermal1-firmware/wiki/Lepton-CCI-through-UVC-extension-units

def command_id_to_control(commandId): return ((commandId & 0x00ff) >> 2) + 1

def get_temperature(devh): buffer = create_string_buffer(2) call_extension_unit(devh, SYS_UNIT_ID, command_id_to_control(0x10), buffer, len(buffer)) return int.from_bytes(buffer.raw,byteorder="little")

- The control Ids can be found in [Lepton Interface Specification](https://github.com/Machriam/PlantMonitor/blob/76-current-temperature-of-ir/Confluence/Documents/LeptonSoftwareInterface.pdf)

[github-actions[bot]]

Changes of Pull Request #77

Commit messages for #76

• 09454f07c58e6ee38b816842511ccbf5c7e604e6 Description of how to convert the commands of the interface documentation into actually usable commands in python: https://github.com/groupgets/purethermal1-firmware/wiki/Lepton-CCI-through-UVC-extension-units Added multiple sample scripts for various tests. It seems like, when the camera is not properly seated, it may send images, but not proper ffc with closing the shutter.
• c5ec1c0ffe44a522771a38fd04a96119c1fe5742 store the temperature along the ir data about every 10 seconds
• face5da20d1a4bb2a64d53d4d68afab9965e4542 temperature data is stored in the filename aswell. This seems to be the easiest solution for storing the data.
• 2f48411e67c48487ef6bc06cc17874a7b96af68b Always stream a struct to the client as its easier to handle
• 9bf7997ede9b1e62a83fff7c92361055cc78f018 last temperature in celsius can now be retrieved when streaming ir pictures