respect80:
It's true.
Those hidden cameras have lights which can /may not easily be detected with bare eyes but can easily be detected by your Smartphone camera. Almost the same way we test run a device's remote before we buy.

AmosAkins:


They are know as infrared rays
It is used by the proximity sensor...
This is the reason you phone screen goes of while you make a call...
It has other applications tho in other devices

Thebwoy:


What If you're are being recorded with a phone camera ?

Sixta:

How would you feel when you enter a room where you are supposedly supposed to be safe and then you realise that your privacy is being infringed on? I am sure you won’t feel safe and secured.

One of the reasons why I made the personal search to identify if someone is playing smart on me by hiding cameras in a room is because I have been a victim before. Once beaten, twice shy!!

In this world where we have smart recording devices and pinhole sized drones, there is a need to be vigilant and to always check if your privacy is being trampled upon. Below are ways to avoid being recorded or photographed secretly:


1. The first thing to do when you enter a room and you are being suspicious, is to turn off the lights in the room.

2. If there are curtains in the room, close them.

3. Open your phone camera and do not turn the flash light on. Turn around the room with your cellphone. When a red dot is found on your screen, that means that a hidden web camera is installed.

4 . If no red dots, then the room is okay. Take note some people have the habit of sleeping stark naked
As simple as this is, it can save you from a social media blackmail or a business contract betrayal.

source: https://www.hitng.info/tech/how-to-detect-hidden-cameras-with-your-smartphone/