A microcontroller based smart area monitor

A micro-controller based smart area monitor has been developed using a GM counter for area monitoring of gamma radiation levels around radioactive source storage and instrument calibration rooms. The area monitor can be programmed to store the radiation levels in a built-in memory module every half or one hour along with the real time. The memory module has a capacity for storage of 1000 readings and hence hourly data for one month can be stored. The monitor has also a RS232C interface for connection to a PC and the stored data can be readily down loaded in to the PC for dose profile analysis, investigation of any over exposure cases and checking radioactive source usage and movement. The monitor has also an alarm function wherein a buzzer is activated when the exposure exceeds an user settable level. The time of occurrence of the alarm condition and the alarm level are also stored in the memory. The monitor covers a range 1mR/h to 100mR/hr. The other features of the monitor are built-in self diagnosis for failure of G.M Counter, EHT, or memory and low power mains operation with rechargeable battery backup for uninterrupted functioning. The design details are discussed. (author)