PIC Microcontroller

This design controls up to 8 devices using a PIC microcontroller (PIC16F84A) connected to the phone line. The unique feature here is that unlike other telephone line based remote control, this device does not need the call to be answered at the remote end so the call will not be charged. This device depends on number of rings given on the telephone line to activate/deactivate devices. A) While constructing the main circuit, make sure you use 18pin sockets (base) for the PIC16F84A. Do not solder the IC directly to the board since you may have to remove it for programming. Before you use the PIC on the main circuit, you have to first program it. To program the PIC16F84A microcontroller: There are lots of programmers on the Internet available to program PIC microncontrollers. Given below are links to some free PIC programmer hardware/software:..

This is the lowest cost dialing alarm on the market and shows what can be done with an 8-pin microcontroller. The complete circuit is shown below. You cannot see all the features of this project by looking at the circuit - most of them are contained in the program. So, read on and see what we have included. Dial Alarm-1 has a single input (although a number of sensors can be placed in parallel on the same input line). The circuit requires a trigger pulse to turn on a BC 557 transistor. This delivers power to the microcontroller. The micro starts to execute the program and outputs a high on GP2 to keep the "turn-on" circuit active. It also turns on the LED in the opto-coupler and this causes the line to be "picked up" via a high-gain Darlington transistor. The micro then dials two phone numbers and executes a series of events to alert the called party of an intrusion...