Research
Design, Development and Performance Study of a Microcontroller-Based Home Security System Using Mobile Phone
Security has been an important issue in the smart phone applications. Here, a security system has been developed that uses a sensor to detect a security violation and informs the owner by calling to his mobile. The system consists of a sensor, microcontroller IC, some relays and a mobile phone that operates when the sensor sense some unwanted breaking of doors, lockers etc. As soon as this occurs the system automatically calls the owner through the mobile phone used in the security system. The system has been designed and developed using locally available components and its performance has been studied. A program has been developed using Flow Code software to drive the system.
Temperature Control of a Hot Plate Using Microcontroller-Based PWM Technique
The temperature of a hotplate used for prebaking, post baking, dehydration baking etc. changes with time. But, in baking purpose the temperature should remain constant. This work concerned with the designing a new and cost-effective microcontroller based PWM temperature controller to control the temperature of a hot plate. PWM controller has been selected because it has faster and accurate response than the conventional on-off controller. Here, the microcontroller senses the zero crossing of the line voltage and generates a pulse for every half-cycle. The width of the pulse is adjusted to change the firing angle of a TRIAC. The TRIAC is interfaced with the microcontroller circuit using an opto-coupler. The temperature of the hot plate can be increased or decreased using two push-button switches. The preset temperature will be saved in EPROM of microcontroller and displayed on an LCD display. The temperature of the hot plate is sensed by a thermocouple and fedback to the microcontroller. The microcontroller keeps the temperature constant by changing the firing angle of the TRIAC. The system has been constructed and tested successfully.
