Design and construction of cellular phone calling detector

Cellular phone detector is an electronic device that when placed some few centimeters away from a mobile phone pulse-blink by a way of lighting a light emitting diode (LED) whenever a call is made to the phone. The ability of the detector to successfully indicate a light on the LED is highly dependent on the distance between the phone and the detector. Accordingly, there is need to improve the distance of separation. The aim of this research project is to design and construct a device that when placed a few centimeters away from a phone lights up a light emitting diode (LED). The signal detected is enabled by a coil used as an antenna which receives signal and then amplified by a transistor which drives the monostable input pin of the IC 555 timer. Thus, a light emitting diode lights up indicating a call made to a phone. This research discovers that as the number of turns of the coil increases and the calling detector is placed far from the phone, the weaker the signal becomes. Future studies will focus on increasing the distance of the separation to any length that is convenient for use.