The automatic water pump controller is used to control the water pump motor. The motor gets automatically switched on when water in the overhead tank (OHT) falls below the lower limit. Similarly, it gets switched off when the tank is filled up. Built around only one NAND gate IC (CD4011), the circuit is simple, compact and economical. It works off a 12V DC power supply and consumes very little power. The circuit can be divided into two parts: controller circuit and indicator circuit. The controller circuit is one which is used for the purpose of controlling the water pump action. When the water level reaches a maximum level the motor turns off and when the water level goes below the minimum level the motor turns on automatically. This circuit consists of a NAND gate IC (4011), three transistors (BC547), two relays with specification 12V, 200ohm 1C/O, four resistors (1K), two diodes (1N4001). The indicator circuit is one which is used to indicate the level of water inside the tank. Depending upon the number of LEDs that glow we can determine the level of water inside the tank. This circuit consists of five LEDs, five NPN transistors (BC547), ten resistors (1K). So, from the glowing of LEDs, one can determine the water level in the tank. This device is very much useful to curb the overflow of water in overhead tanks which in turn favours conservation of water. With further advancements, it can be used to check the level of water in dams. ..................................
Automatic Temperature Control Fan
The automatic temperature control system is a very essential feature of a factory or an industry. In most of the case the temperature plays a vital role in the process of manufacturing or the process carried in that factory or industry.
The most common and simplest way of controlling temperature is by using a fan which is automatically connected to a network such as it is switched on when the temperature of the surroundings increases.
The change in temperature of the surroundings can be sensed with the help of thermistor or a sensistor. These electronic components sense the temperature of the surroundings. When there is a change in the temperatue tempetature then these electronic components start to conduct the electric current. This is the main principle of the automatic control devices. These devices can be extended to an extent that we can set the temperature when the fan should rotate. ................................
A/C Update: The Logic Behind Automatic Temperature Controls
By Larry Carley email
February 01, 2006
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Many new cars and trucks now have automatic temperature control (ATC) systems that not only regulate cooling but also heating for year-round passenger comfort. Most of these systems have their own computer that may be built into the control panel head, located elsewhere or integrated into the body control module. One thing’s for sure: the more sophisticated the system is, the more complex are its control electronics and operating logic — which increases the odds of something going wrong. Simple manual temperature controls are being replaced with digital push button settings and computer logic. Today’s new car buyers want separate controls for the driver and front seat passenger, and triple-zone rear A/C in minivans and SUVS with a separate control head in the rear to keep the kiddies or mother-in-law comfortable. ATC systems require a complex array of internal and external sensors including ambient air temperature sensors, interior temperature sensors, outlet duct and evaporator temperature sensors, pressure sensors, humidity sensors, blend door position sensors and sunload sensors. On the 2004 Acura TL there’s even a global positioning sensor (GPS) that allows the control module to determine the vehicle’s orientation to the sun...