Use Cam Motion Detection in Homekit

I tried to use the Cam 2C as a motion detector to activate other accessories in my Homekit setup. However it seems that the motion sensor in the Cam 2C is not functioning if all 4 options in the security mode are disabled, i.e. not recording, no notification and no cam or home base alarm. Pretty sure detection was not working under these settings as nothing happen when I danced in front of the cam under the Motion Test Mode in the app.
I need to setup this way as I only need the motion detection to activate, a light for example, when I am at home and obviously do not need a recording, notification or alarm to remind myself being there. So all off in the Home security mode.
I know it would be more appropriate to use a sensor rather than the cam, but I do need all the other functions when I am away (so all 4 options are on in the Away security mode).
Is there a way to achieve this with the Cam 2C rather than having a separate motion sensor for the lights?