TTL/CMOS, RS232 LOGIC CONVERTER

This s a simple TTL/CMOS . RS232 logic converter. That is it convert TTL/CMOS to RS232 as RS232 to TTL/CMOS logic. It is used t synchronous PIC microcontroller with USART. TTL is -5 t +5V and RS232 is -30 t +30. MAX232 is a dual/receiver. It include capacitive voltage generator to make RS232 logic level from a 5V supply.Each receiver in the MAX232 convert RS232 input into TTL/CMOS(5V). As each driver in the MAX232 convert TTL/CMS input into RS232 logic level. The four capacitors used for this conversion.

ATMOSPHERIC MEASUREMENTS USING WIRELESS ROBOT

The AMWR was designed for application in inaccessible places, or in inhospitable situations for humans. A full scale version of AMWR could be used for many real world applications such as military reconnaissance, extreme condition (environment) vehicles, or in artificial intelligence robotics. Another application could be in schools, colleges, and universities interested in experimentation and development of robots. AMWR, the remotely controlled robot, has several key components.

 This robot consists of a PIC 16F877A microcontroller interfaced with the motor controls of a DC gear motor. This microcontroller is responsible for decoding the correct control signals when given a control byte, and sending these control signals to the motor controls. In addition, to these two sensors are also connected to the microcontroller. These sensors are placed to measure temperature and humidity. Remote communication to the AMWR is accomplished using zigbee. The remote control module using zigbee is connected to a pc using a serial cable (RS-232) at baud rate 9600.In order to provide feedback from the robot; an android mobile phone camera is attached to the robot. A 2.4 GHz wireless link provided, along with the camera used to communicate with the controlling PC. PLC software running on the controlling computer is responsible for converting instruction given by a user into a byte code, and sending it to the zigbee module via db9 serial port of the PC.

The major objectives of the robot are embedded control of a robot, atmospheric condition measurements, zigbee based communication, live video feedback, and PC-based direction. Zigbee can penetrate walls and be used in places where a wired network is either not suitable or cannot be established. The advances in the wireless technology have made it possible to establish a network just by placing the communicating nodes at the required places and switching on the transmitters in them. It is possible to have great transfer rates even at long ranges. With such usefulness and many more features, a wireless network is the surely needed in places where it is not possible to establish a network using wires. Also, in case of cave-ins, or an explosion the wire may get damaged making the entire network useless.

RAIN DETECTOR USING ASTABLE MULTIVIBRATOR

Here we going to make a rain detector using astable multivibrator and simlpe conitinuouity tester.
These circuits are we already learned in my previous post. We all know water is a precious thing in earth. Also  it is less in earth so we want to protect and reduce the use of water.
Use of this circuit we can save the rain water whenever the raining occur.

SIMPLE CONTINUITY TESTER

In this we are going to make and study about simple continuity circuit. In electronic field multimeter is the very usefull instrument. Continuity testing is used in electronic circuits for the continuity check. It is the part of multimeter function. Here we sepperating the continuity function of multimeter. It consist of a simple LED , resistor and 9V power supply. The two legs are place where the continuity to be measured. If the circuit is closed the LED will glow. Otherwise it continue without glow. It is very simple to use .





 Components for wiring this circuit

 R - 350K
 LED
 9V battery

SIMPLE AUTOMATIC STREET LIGHT CIRCUIT

It is the circuit for automatic street light. The main part is a photodiode. And light activated relay. It is nothing but a circuit which operate a relay according to the light input. This circuit set up such a way that the LIGHT will glow until the ligth is incident on the photo diode.
In the absence of light, current into the transistor through the base is sufficient enough to turn the transistor on. This makes the 5V relay operate and the LIGHT gets 230V ac  and it glows. When the light falls on photo diode , its resistance decreases and the current through it increases. This cause the current through the transistor to decrease and the transistor turns off. Then the current through the relay stops and it gets deactivated . In turn , LIGHT turn by the absence of 230V ac.
Componets for wiring this circuit
SL100
R1 = 10K
photo diode
5V relay
lamb
230V ac

LIGHT ACTIVATED RELAY

A light activated relay is nothing but a circuit which operate a relay according to the light input. This circuit set up such a way that the LED will glow until the ligth is incident on the photo diode.
Photo diode is special semiconductor diode operated in reverse biased condition. In no light condition it offer very high resistance. Only current existing in it is the reverse satuaration current due to the minority carriers. When the light falls on it reverse through it will increase.
In the absence of light, current into the transistor through the base is sufficient enough to turn the transistor on. This makes the relay operate and LED circuit gets completed and it glows. When the light falls on photo diode , its resistance decreases and the current through it increases. This cause the current through the transistor to decrease and the transistor turns off. Then the current through the relay stops and it gets deactivated . In turn , LED circuit opens and it glowing.
Components for wiring this circuit
SL100
R1 = 10K
R2 = 100Ω
Relay 5V
photo diode
LED
Vcc = 10V