Phone detector for class rooms - Amplify specific range frequencies and trigger a led
Budget: £250 – £750 GBP
I need to amplify all frequencies starting from 1.6Ghz to 300Ghz.
using a rotary switch would be good to select how many opamps will pass the signal in order to implement adjustable sensitivity. The circuit is to detect phones during exams.
The available schematics on internet are based on alternating electric field detection , which is not what needed. The LM358 that some of them are based respond only to frequencies till 0.7Mhz, when 4g starts from 2Ghz. If multiple opamps used in series then they respond to every electromagnetic field and have false detection.
using a rotary switch would be good to select how many opamps will pass the signal in order to implement adjustable sensitivity. The circuit is to detect phones during exams.
The available schematics on internet are based on alternating electric field detection , which is not what needed. The LM358 that some of them are based respond only to frequencies till 0.7Mhz, when 4g starts from 2Ghz. If multiple opamps used in series then they respond to every electromagnetic field and have false detection.