AT89C2051/4051

Figure 1 shows the circuit diagram of proto board. All port connections are available for user interface around the proto area including the power supply pins. MAX232 serial driver is used to provide a 3 wire RS232 interface for connecting to the PC or other rs232 devices. Switch S1 provide a manual reset to u-controller.

The heart of the synthesizer is a set of 2 Analog Devices AD9850 direct digital synthesis (DDS) chips. These provide 2 channels of sinewave output which may differ in frequency and relative phase. The output stage of the synthesizer also includes separate variable attenuators for the 2 channels. These attenuators have a range of 0.0 - 63.9 dB of attenuation, in 0.1 dB steps. The user therefore has control over five parameters: 2 output frequencies, 2 output attenuations, and relative phase between the 2 channels.

Its a digial clock which make use of AT89C4051 to work as a Real time clock. Port 1 of the controller (AT89C4051) is used as the data lines for the LCD (starting from pin 7- pin14 of LCD). As you can see there is not much change in the hardware except the LCD, here i am using a 20 x 4 lines LCD display.

This is an 8-input x-output audio/video switch module to be controlled from a computer, for example from the parallel port. Each audio/video output can be switched to any of the 8 inputs, separately. One module drives one audio/video output and has a 34-pin connector to plug into the system interface.You can use video OPA-s on the 4051 output instead. Note that you can get full integrated video multiplexers from Maxim.

The Project presented here waters your plants regularly when you are out for vocation. The circuit comprises sensor parts built using op-amp IC LM324. Op-amp’s are configured here as a comparator. Two stiff copper wires are inserted in the soil to sense the whether the Soil is wet or dry.

This Project takes over the task of Ringing of the Bell in Colleges. It replaces the Manual Switching of the Bell in the College. It has an Inbuilt Real Time Clock (DS1307) which track over the Real Time. When this time Equals to the Bell Ringing time, then the Relay for the Bell is switched On.

In spite of the improvement of communication link and despite all progress in advanced communication technologies, there are still very few functioning commercial wireless monitoring systems, which are most off-line, and there are still a number of issues to deal with.

The Clock Controller V1.1 was designed to be an exemplary of using 'C' language to control timer0 interrupt, 7-segment LED and keypad scanning. It provides 1-bit sink current driving output, for driving a relay, opto-triac, say. Many projects requiring 7-segment display and keypad interfacing may get the idea from the Clock circuit and software.

This Project Components tester can be used to check the electronic components such us Diode, Transistor, Capacitor, IC555, IC741 and Continuity. The whole circuit was controlled by the Microcontroller AT89C52. The circuit has an LCD display it was used to display the Text messages over it. The system will display the conditions of the device on the LCD display.

This Project can be used with the three phase Induction motors. The circuit will take the full control of the motor and it will protect the motor from several faults such us over voltage and under voltage and the circuit will switch on the motor under safety conditions.