sl technological sevices

  ABSTRACT         This project work describes the construction and designing of 12volt car battery charger with USB port for charging mobile phones. The charging process is focus more on 12volt lead car batteries commonly used in vehicles. This design was done by using I.C LM7812 and LM7806 with transformer of 230 volt and series of other electrical component highlighted in the work to achieve our goal. The charger was able to charge lead car batteries within the maximum of 70mAh faster and with a feasible port charging usb enable cell phones, The design also has LED indicators which determine the battery level when fully charged or a completed down battery. Unlike any other battery charger, this project is about the combination of battery charger circuit with usb charging circuit. The charging process is halt manually by turning of the circuit to displayed full 3LED light as fully charged battery. The theory, design, circuit analy...

This diagram is a series of circuits Mobile Cellphone Battery Charger. Stops charging when battery is full charged, Portable unit Charging of the mobile phone, cellphone battery is a big problem while traveling as power supply source is not generally accessible. If you keep your cellphone switched on continuously, its battery will go flat within five to six hours, making the cellphone useless. A fully charged battery becomes necessary especially when your distance from the nearest relay station increases. Here’s a simple charger that replenishes the cellphone battery within two to three hours.   Basically, the charger is a current-limited voltage source. Generally, cellphone battery packs require 3.6-6V DC and 180-200mA current for charging. These usually contain three NiCd cells, each having 1.2V rating. Current of 100mA is sufficient for charging the cellphone battery at a slow rate. A 12V battery containing eight pen cells gives sufficient current (1.8A) to ch...

Did you ever think that how the street lights automatically turn ON in the night and turn OFF automatically at morning? Is there any person who comes to ON/OFF these lights? The following circuit that described below which perform this job automatically. This circuit employed the output from an uncomplicated light/dark activated circuit and oblige a relay in its output which can be further attached to switch ON/OFF a street light and electrical application in a household also. Many of the people have a phobia of darkness, so to assist them in such situation, we have explained a simple circuit. It will automatically turn on street light in the way of LEDs or bulb coupled with relay, it is well enough to see the object nearby. This circuit is very much easy to work and also the battery power consumed by the circuit is very low because of the very few components used in the circuit. The whole circuit is based on IC LM741 which is basically an operational amplifier which c...

A light sensor is a passive sensor that is used to indicate the intensity of the light by examining the radiant energy that exists in a certain range of frequencies. In the spectrum of electromagnetic waves, the ranges of frequencies that are used to detect using a sensor are between infrared to visible and up to ultraviolet. Light sensors convert the light energy in the form of photons to electrical energy in the form of electrons. Hence, they are also called as Photo Sensors or Photo Detectors or Photo Electric Devices. Light sensors or Photo Sensors can be classed into three types based on the physical quantity that is affected. The main classes are Photo resistors, photo voltaic and photo emitters. Photo emitters generate electricity when exposed to light. Photo resistors change their electrical properties when illuminated. Based on the above classes, the following classification of devices can be made. Photo Emissive Cells:  These types of photo devices re...

Most of the schools and offices have intercoms to communicate with people inside a building or a particular campus. These are just like landline phones but, you do not need an operator, the voice received from one end will be directly transferred to the receiver on the other end.  In this circuit we are going to build a very Simple Intercom Circuit using which you can communicate two ways locally within your house or school. This project brings in the childhood memory of using matchboxes with thread to build a simple telephone. So now let’s take it to the next level by building an electronic circuit (amplifier) to transmit voice from one end to another end. Materials Required: LM386 Audio Amplifier Speaker (2Nos) Microphone (2Nos) Resistors (10k, 4.7k, 10k) Capacitor (0.1uf, 0.1uf, 10uf, 10uf) SPDT switch Breadboard Circuit Diagram and Explanation: The complete circuit diagram of this Intercom Project is given below. As you can see the circuit i...

A visitors counter is a counter which simply count the number of visitors . A visitor is counted only 1 time per day. Often we see visitor counters at stadium, mall, offices, class rooms etc. How they count the people and turn ON or OFF the light when nobody is inside? Today we are here with automatic room light controller project with bidirectional visitor counter by using Arduino Uno. It is very interesting project for hobbist. Components Arduino UNO Relay (5v) Resisters IR Sensor module 16x2 LCD display Bread Board Connecting Wires Led BC547 Transistor The project of “ Digital visitor counter ” is based on the interfacing of some components such as sensors, motors etc. with arduino microcontroller. This counter can count people in both directions. This circuit can be used to count the number of persons entering a hall/mall/home/office in the entrance gate and it can count the number of persons leaving the hall by decrementin...

In this project, we will see the Automatic Room Lights using Arduino and PIR Sensor, where the lights in the room will automatically turn ON and OFF by detecting the presence of a human. Such Automatic Room Lights can be implemented in your garages, staircases, bathrooms, etc. where we do not need continuous light but only when we are present. Also, with the help of an automatic room light control system, you need not worry about electricity as the lights get automatically off when there is no person. So, in this DIY project, we have implemented Automatic Room Lights using Arduino and PIR Sensor. Over view Automatic Room Lights System using Arduino is a very useful project as you need not worry about turning on and off the switches every time you want to turn on the lights. The main components of the Automatic Room Lights project are Arduino, PIR Sensor and the Relay Module. Out of the three components, the PIR Sensor is the one in focus as it is the main dev...