Use Your Phone
You can use your phone’s light to see how a camera looks while under a flashlight. You can detect night vision cameras by turning the lights off and using the front facing camera on a phone in order to find infrared LEDs.
Night Vision
Hutchins explained: “The front-facing camera is the only one that tends to work because the back-facing one has an infrared filter. I wouldn’t rely on this method because people usually don’t shower in the dark, so if they’re placing cameras in the bathroom then they’re probably not going to bother with night vision.”