Simple Solar Power System. Design Note 18

Solar based power system is now becoming popular to save energy and money. It is easy to install a simple 100 Watts Solar lighting system for outdoor lighting. No need for constructing the circuits and all necessary units are readily available and anybody can install this. It runs on a 12 volt Car battery and no switching is needed. It turns on the outdoor lamps around 6 p.m and turns off at 6.a.m. The car battery can power the system for minimum 3 years so it is very cost effective. Another advantage is that, the outdoor lights will automatically turns on / off even if the inmates are not in home giving some security. Cost of the system is around Rs.5000 including battery.
The system requires the following:

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Solar Power Supply. Design Note 15

IMAGEYou can make this Solar Power supply as your work bench power supply for testing prototypes. It delivers variable voltage from 1.5 volt to 12 volts with a current up to 300 milli amperes. It can also be used to charge batteries during day time. By using the Pot, it is easy to set the output volt from 1.5 to 12 Volts.
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How to remove noise from 433 MHz receiver. Design Note 13


The handy low cost 433 MHz Transmitter and Receiver pair is now widely used in Arduino based circuits. But one of the serious problems with the Receiver is its inherent property of accepting lot of noise from the background. This gives erratic output data which causes error reading. If the output is connected to an audio amplifier, hissing sound appears in the speaker when the receiver is in standby without receiving the signals from the transmitter. So careful designing of the power supply and a Glitch removing circuit will considerably reduce the noise from the data out of Receiver (Rx).

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TL 431 Shunt Regulator. Design Note 11

TL 431 is an Adjustable Precision Zener Shunt regulator that can be used to get a desired output voltage from a power supply. It’s output voltage can be set to any value between 2.5 volts and 36 volts using a voltage divider comprising two resistors. It can be used to design, Battery Monitors, Battery chargers etc. Along with two resistors, TL431 give a regulated precise output voltage. Here we discuss how TL431 is used to make a Battery monitor for Solar powered Inverter and a 5 volt power supply.
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BT 8031 Melody IC. Design Note 10

BT 8031 –XX series is a CMOS LCI chip is a double sound source with a ROM to play prearranged melodies. The ROM has 127 words and can store upto two melodies with double sound sources. The IC is a three pin type like the popular melody IC UM66. It works between 2-5 volts and ideal voltage is between 2.2V to 3.1V and has very low current consumption ideal for use in battery power supply. Its output cannot drive a speaker directly, so a transistor amplifier is needed.
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ATmega328 Microcontroller. Design note 9

ATmeg328-Microcontroller.ATmega 328 is the single chip Microcontroller from Atmel and belongs to the mega AVR series. Atmel corporation is an American based designer and manufacturer of semiconductors founded in 1984. ATmega328 is now widely used in many projects where low cost microcontroller is needed. The most common implementation of ATmega328 is on the Arduino development platform namely Arduino Uno and Arduino Nano boards. A low power alternative of ATmega328 called ATmega328P is also used now which is a pico power version.

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Hall Sensor. Design note 8

Hall sensor is a device that generates output current based on the magnetic field in its proximity. When a current carrying conductor is placed in a magnetic field, a voltage is generated perpendicular to the current and the field. This phenomenon is called as Hall Effect. The Hall sensor has a thin semiconducting material called Hall element. A current is passed through the Hall element in a direction perpendicular to the output connections. In the absence of a magnetic field, current distribution is equal without any potential difference across the output. When a perpendicular magnetic field is applied, a force called Lorentz force disturbs the current distribution and a potential difference develops across the output. The output voltage is called as Hall voltage (VH ). Lorentz force is the force acting on the moving charge carriers in a magnetic field.
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