You can use an external battery, the constant voltage of the external power supply is 5V~12V, and the maximum current supports 2A. You cannot use an external power supply that exceeds the voltage, which will cause the product to burn out. 

Check the "PIR Sensitivity" parameter setting. Set the sensor level to "High" for warm ambient conditions and "Low" for cold weather use. Try setting your camera in an area where there are no heat sources in the camera's field of view. Try to set the camera on a stable and immovable object, ie: a big tree. If the person/animal is moving fast, it may move out of the camera's field of view before taking the picture. Move the camera further back or redirect the camera. 

Make sure the SD card is not full. If the card is full, the camera will stop taking pictures; make sure the battery is fully charged; make sure the camera mode switch is slid to the "ON" position; please format the SD card with the camera before use or when the camera stops taking pictures. 

Please check if the protective film of the PIR Fresnel lens has been removed. 

The product does not have a WiFi hotspot, it is an ordinary camera