The principle of particle detection technology based on commodity digital cameras is similar to that of optical microscopes, and the imaging performance is related to the light-absorbing properties of the detected objects. For those substances that do not absorb visible light or UV light, the detected object first needs to be processed to be given light-absorbing properties, such as being introduced light absorbing or fluorescent groups in molecular structures, or being combined with light absorbing or fluorescent substances, and then the objects can be detected by detection system based on commodity digital cameras. Below we showcase successful applications of commodity smartphone cameras to the detection and characterisation of microscopic chemical and biological objects.