Arduino IDE Spresense manual exposure timing

[hintzc]

I see from the update lists that v1.1.1 et seq. supports manual exposure timing, but I cannot find any examples or coding other than the .setAutoExposure(false); command in the API.

Can someone point me to an example or project that is controlling manual exposure timing? and use the shutter priority exposure control to get down to 1/8s (Long AE mode)?

thank you.

[TE-KarlKomierowski]

Hi @hintzc said

I looked into this and it sees you're right about the arduino library missing the absolute exposure time set function.

I have not found a project using manual exposure time but I looked into the Nuttx driver handling for the isx012 camera chip. Extracting information from the driver I added a function to the Camera driver:

Campera.cpp:

CamErr CameraClass::setAbsoluteExposure(uint32_t exposure_time_ms)
{
  return set_ext_ctrls(V4L2_CTRL_CLASS_CAMERA,
                       V4L2_CID_EXPOSURE_ABSOLUTE,
                       exposure_time_ms);
}

Camera.h

CamErr setAbsoluteExposure(uint32_t exposure_time_ms);

In the camera sketch you find under File->Examples->Camera

      Serial.println("call takePicture()");

      /*Following three lines are new*/
      Serial.println("Setting autoexp and absolut exp"); 
      Serial.println(theCamera.setAutoExposure(false));
      Serial.println(theCamera.setAbsoluteExposure(1));
     
 CamImage img = theCamera.takePicture();

Setting the exposure time to 1 gave me very dark images so and increasing it gave very light images so I it seems that this fix would do it for you.

Br
Karl Komierowski