In today’s greenhouses, many parameter measurements are required to monitor and control for the good quality and productivity of plants. But to get the desired results there are some very important factors which come into play like Temperature, Humidity, Light and Water, which are necessary for a better plant growth. Keeping these parameters in mind I have built an Automatic Green House Controlling and Monitoring System over GSM module using Arduino. This system is very efficient for growing good quality plants. The other important part of this project is that it is fully automatic. Arduino automatically turns on and turn offs the appliances.
It has become necessary to verify the identity of a person or visitor before opening the door as he may be a burglar . This switchless bell circuit will help you to [[wysiwyg_imageupload::]]identify who is standing at the door as it that activates through the puff of your breath or with a clap. Only those who know the place of secret bell would puff out before the hole of the switch box and now door can be opened without any fear. Interestingly, this circuit does not use a microcontroller but only a BC547 transistor, a microphone, buzzer, switch, LED, a few resistances and capacitances.This Transistor based secret bell circuit is based on the property of the transistor to amplify weak signals. In this, the condenser mic fitted inside a hole of a switch box will trigger the bell on detecting the change in air pressure as you clap or puff your breath.
The microphone converts the mechanical vibrations into electrical signals but the amplitude of these signals is not enough to drive a speaker. In this project, these [[wysiwyg_imageupload::]]signals are amplified before connecting to the speaker.Facts about the type of transistor used in the circuit: 1. This circuit is based around transistor BC 547, an NPN transistor. 2. Providing a maximum gain of 800, this transistor is widely used in amplification and switching circuits.3. The transistor shows highly stable working at quiescent point (Q-point) once properly biased using a DC source.Read more to find out how the circuit is constructed and how it works.
The commonly used IR transmitter has a limited range. This circuit based project can be used to increase its range. This is achieved by amplifying the signal [[wysiwyg_imageupload::]]which is fed to the IR Led for transmission.Major function in assisting IR LED to increase its range is carried out by two devices: BC 547and a NE555 Timer.BC 547 is a NPN transistor which is generally used in common emitter configuration for switching and amplification purposes. In the circuit, the transistor works in its usual configuration and is using a voltage divider procedure for biasing.NE555 is a popular 555 timer used for several applications as it generates pulses of accurate width. It can be operated in monostable and astable modes.
Here is an Unusual LED indicator for the Battery. It turns on fully when the battery voltage is above 13 volts and starts to blink faintly when the voltage drops below 12 volts .Finally the LED turns off when the voltage drops below 10 volts. Its design is unusual because the LED driver transistor is…