EFY Magazine projects

[pushycat]

An effort to put up Construction projects published in Electronics For you Magazine will be done here in this thread regularly. If any other member too has any access to any construction articles from the magazine, is most welcome to post it here. All articles will include schematics, full articles with PCB layouts and codes. Thus material whatever available from the magazine will be posted here, and these are not my projects. Any claims about its non working or discussions about the same may be continued on the regular discussion forums. This thread will be exclusively for posting projects only.
Requests for any EFY published projects such as Code or other info may be continued on this thread:
EFY Magazine projects Requests Code or More
http://www.sonsivri.com/forum/index.php?topic=37591.0

EDIT: Ask for code or hijack this topic and your post will be deleted, and a warning given. Help keep topic clean

[pushycat]

Serial Interface using Phyton (EFY April 2017)
Presented here is a project for a simple transistor’s output characteristic curve-tracer program through the serial interface and PIC microcontroller using Python programming language. Output characteristic curve of a transistor is automated using Python software and serial interface. Application software for collecting the measured value and displaying it on the monitor screen is developed using Python. Engineers and academicians have been using high-level languages like Visual C++, Visual Basic and Delphi for connecting their gadgets/embedded systems with the computer for measurement and control purposes for a long time. Recently, many shifted their preference to Python as their computer language for measurement and analysis. The main advantage of using Python is the support of a large open source community. Python is an interpreted programming language like BASIC, which saves
considerable time during program development because compilation and linking are not required. Programs written in Python are typically much short-
er as compared to ones written in C or C++. Python can be used for writing standalone programs and scripting applications. It is free, portable, powerful
and remarkably easy to use.

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[pushycat]

DUAL-LASER SECURITY SYSTEM Using An Old Feature Phone (EFY April 2017)
A  security system having a single laser beam may not be very effective as any moving object or animal can interrupt it, causing a false alarm. Presented here is a security system having two laser beams with calling alert feature, using a basic mobile phone (old model), also known as feature phone. The security system can be used in a restricted area like a farm or as a home security system. When an intruder cuts or interrupts both laser beams at the same time, an alarm sound is generated and an alert call is made to your current mobile phone.

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[pushycat]

Wireless GATE ALARM (EFY April 2017)
This wireless gate alarm uses infrared (IR) and 433MHz RF modules. IR transmitter unit emits 36kHz signal and is fitted on one side of the gate’s frame. IR
receiver unit and RF transmitter module, along with the encoder, are fitted on the opposite side of the gate’s frame. The alarm unit is kept inside the house, and it uses 433MHz RF receiver module and musical alarm circuit.

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[pushycat]

Configurable DC-TO-DC CONVERTER (EFY May 2017)
Most kits with embedded microcontrollers (MCUs) operate off a single power supply (VCC) source like 5V or 3.3V. But for some experiments you need one or more positive voltages higher than VCC and one or more negative voltages lower than ground. Often, the required current is in several millimperes (mAs). In such cases, you may use ICL7660, ICL7660A or similar integrated circuits (ICs) for the power supply. But voltage and current provided by a single ICL7660 is not sufficient, so you may need two or more ICs in parallel or cascaded to meet the requirement. This article describes a universal configurable module that uses three ICL7660 ICs. The module is flexible and allows all basic configurations for ICL7660 and similar ICs.

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[pushycat]

Water pump dry run guard (EFY may 2017)
Here is an effective solution for protection of household submersible water pumps against dry running. Minimum water-level monitoring feature in the circuit is realised using suspended sensor probes to ensure that the water pumps will not run under a dry condition. Besides, switch-on and return-delay features prevent the pumps from unwanted brief operation when handling turbulent underground water.

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[pushycat]

Make your own remote controlled robot (EFY May 2017)
To control a robot, the signal is usually sent through a wireless system using radio frequency (RF) and infrared (IR). To send an IR signal, you need a transmitter and a receiver with an encoding and decoding system. The simple circuit presented here can control the movement of a robot using an IR remote that is used for a TV or DVD player, or an equivalent IR remote.The basic working principle of this project is that the signal sent by the IR remote on pressing Play/Record button on the remote is saved in EEPROM of the microcontroller (MCU) in record mode. It plays back the same code (signal) when you press the same button in play mode. The program for the MCU can save 4-bit code (0 to F hex code) in record mode and output the same 4bit code when the button is pressed in play mode. Using the combination of these four bits, two motors installed on either side of the robot (third one being the caster wheel) can be controlled through a motor driver IC. Thus, different codes are used to control different movements of the robot.

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[pushycat]

PC based Oscilloscope using Arduino (EFY June 2017)
Oscilloscopes are an essential tool for electronics hobbyists and professionals to verify that their designs would work as expected. PC-based oscilloscopes score over standalone oscilloscopes due to their compact size, low cost and ability to do offline analysis. Here we describe how you can make your own oscilloscope at a very low cost using your PC and an Arduino board as the hardware for signal acquisition. You can use this oscilloscope to capture frequency signals up to 5kHz. The Arduino board, the heart of the oscilloscope, reads the values from its inbuilt analogue to-digital converter (ADC) and
pushes these to the PC via USB port. We have provided here an Arduino sketch, which you can compile and load directly to the Arduino. You also need to install an executable file or application in your Windows PC. This application works as the front-end to plot input signals as waveforms on your computer screen.

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[pushycat]

AUTO REVERSIBLE DC MOTOR With Speed And Rotation Control (EFY June 2017)
DC motors are widely used in different machines, mechanisms and motion controls in manufacturing and processing industries. In these machines, it is often required to control speed, direction and the number of rotations of the motor. Some applications require only speed control, some only rotation control and some only direction control. Many applications require control of two or all three parameters.

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[pushycat]

ULTRA-LOW-POWER SENSOR HUB Using nRF24L01 Modules (EFY June 2017)
Presented here is an ATmega328P microcontroller-based ultra low-power sensor hub using nRF24L01+ radio frequency (RF) transceiver modules having transmitter and receiver units. The transmitter sends humidity and temperature values of a place to the receiver kept at a remote location for display on an OLED module. The nRF24L01+ module used in the receiver unit is a 2.4GHz transceiver suitable for ultra-low-power wireless applications. It is designed for operation in ISM band (industrial, scientific and medical radio band) of 2.400-2.4835GHz. The nRF24L01+PA and LNA module used in the transmitter unit is similar to nRF24L01+ but has built-in power amplifier (PA) and low-noise amplifier (LNA) circuits, which help transmit the signal to a longer distance and achieve more stable performance for industry standard applications. The search for a low-power system started when some EFY readers questioned a DIY of mine, saying that ATmega328P processor would not sustain 3.3/5 volts. But it worked well because of the extreme low power capability of the ATmega processor. More detail is provided under extreme low power sub-head of this article.

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[pushycat]

VOTING MACHINE Using AVR Microcontroller (EFY July 2017)
Polling by electronic voting machines (EVMs) has become a norm during elections. Unlike paper ballot systems, EVMs are safe and reliable as these rule
out the possibility of invalid voting. These are more economical and efficient too. Their compact size saves transportation costs. Here we describe the design of an electronic voting machine based on ATmega16A microcontroller. To cast a vote, users need to press the key against the name of the candidate of their choice. The vote is automatically saved in the microcontroller, and simultaneously the LCD shows the message “Thank You.”  The circuit of the
electronic voting machine is built around ATmega16A microcontroller (IC2), IC 7805 (IC1), a 16×2 LCD (LCD1) and other associated components.

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[pushycat]

Arduino-Based SMARTPHONE CONTROLLED ROBOT CAR (EFY August 2017)
Nowadays smartphones can be used to control a host of electrical and electronic devices including motors, music systems and lights. Here we present
an Arduino based robot car, which can be controlled using an Android smartphone having Arduino RC application installed in it. This bot receives commands from your smartphone with the help of a Bluetooth. The ATmega328 chip on the Arduino Uno board comes with a bootloader, which allows you to burn the program to the chip without an external  hardware programmer. After the chip is programmed, it can be removed from the board. The board can be powered from USB connection or external power supply such as batteries or AC/DC adaptors. After connecting the power supply to Vin pin, you get regulated 5V and 3.3V DC on the respective pins of the Arduino board. 5V is used to power the HC-05 Bluetooth module. Serial pins 0 (RX) and (TX) of Arduino are used to communicate with HC-05 module. Pins 4 through 7 are connected to H-bridge motor driver L293D IC. Out of these four pins, pins 5 and 6 provide 8-bit PWM output using analog Write( ) function defined in the asc_car.ino Arduino sketch. Pins 2 and 3 of Arduino (not used in this project) can be used for additional functions like controlling lights, horn, etc.

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[pushycat]

Fan Speed Regulator Using PIC16F73 (EFY Aug 2017)
Voltage dips in mains supply make fans run very slow, leaving you sweaty through hot summers, especially if you don’t own an air-conditioner (AC). Voltage may also dip because of an AC drawing a large current, causing the fan to slow down. The so-called fan regulators fitted on the switchboard for speed control merely reduce the fan speed, not increase it. Earlier, regulators used to have resistors that got connected in series with the fan to drop the voltage and hence the speed. These had a rotating switch with steps 1 to 5 to set the speed below normal, and were fitted on the panel board along with the fan switch, light switch and other power outlet sockets.

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[pushycat]

BATTERY CHARGER And DISCHARGER  Using USB Power Supply (EFY Sept 2017)
Gadgets like electronic toys and musical players commonly use 1.2V rechargeable batteries in capacities ranging from 200mAh to 2800mAh,
which need to be charged and maintained regularly. Here we present a simple and low-cost device that can charge or discharge up to four
1.2V rechargeable batteries simultaneously with maximum current of around 100mA per battery. As the device uses USB power, it doesn’t
require any external power supply. Circuit and working Circuit of the battery charger and discharger with USB power supply is shown
in Fig. 1. It is built around four 30-ohm, 1-watt resistors (R1 through R4), four 1N4007 diodes (D1 through D4), nine LEDs (LED1 through
 LED9), a TL431 shunt regulator (IC1), an LM324 quadruple op-amp (IC2), four 2.5V, 200mA small bulbs and a few other components.

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High-Fidelity FM TRANSMITTER (EFY Sept 2017)
FM broadcasting is radio broadcasting using frequency modulation technology. In order to attain high-fidelity broadcast of music and speech, all audio frequencies up to 15kHz must be transmitted. The low-power transmitter presented here achieves that using simple and readily available components. Its output frequency is locked to 96MHz using the phase-locked loop (PLL) approach. The circuit is built around dual D-type positive-edge-triggered flip-flop 74AC74 (IC1), ripple carry binary counter CD4060 (IC3 and IC5), low-power audio amplifier LM386 (IC6), phase-locked loop CD4046 (IC4), 5V voltage regulator 7805 (IC2) and a few other components.

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Automatic DRIP IRRIGATION SYSTEM (EFY Oct 2017)
Conventional irrigation method wastes a lot of water, leading to a high cost of electricity to run the pumpset for irrigation. Automation can help save water,
electricity as well as human efforts. This can be achieved with the help of a single soil-moisture sensor and an AVR microcontroller. Here we present such an automated plant watering system that senses the moisture level of the soil and automatically switches the pump on when the power is ‘on.’

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[microkid]

BIPOLAR POWER SUPPLY With Adjustable Regulators (EFY Oct 2017)
LM317T and LM337T ICs are well-known, low-cost adjustable voltage regulators capable of delivering up to 1.5A current output with power dissipation of up to 20W. LM317T produces a positive output voltage, while LM337T produces a negative output voltage. It is useful to have a bipolar power supply with LM317T and LM337T producing symmetrical output power. However, adjusting both output voltages simultaneously is an issue. The usual solution is to build a tracking voltage regulator with operational amplifier, which tracks the positive or negative output of the power supply. But here power supplies and other parameters of the operational amplifier can be limiting factors for the required power output. Another solution is to use a stereo potentiometer (potmeter) to adjust both the output power supplies simultaneously. Good quality stereo potentiometers have small differences (of about ±5%) between the two outputs. If this difference is too large, you may use additional potentiometers to adjust the output voltages to exactly the same value. Here we present the circuit of a bipolar power supply with LM317T and LM337T adjustable regulators. The circuit provides the facility to adjust output voltages more precisely with individual potentiometers. Also, output voltages can be adjusted from near-ground levels, not from the typical ±1.25V.

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[pushycat]

Single Wire 4x4 Matrix Keypad Using AVR (EFY Oct 2017)
This tutorial demonstrates a different way of interfacing a 4x4 matrix keypad with ATmega32 AVR microcontroller. Keypad is one of the most important input devices used in electronics projects. It is one of the easiest ways to give commands or instructions to an electronic system. But when designing a traditional matrix keypad, you require more number of input/output (I/O) pins. For example, if you are developing a 4x4 keypad of 16 keys, you require eight digital I/O lines of the microcontroller device. This project uses only a single analogue pin to achieve the same goal, so the remaining pins are available for other purposes.  The system consists of a 4x4 keypad that inputs data to the microcontroller through a single wire, ATmega32 microcontroller for processing the received signal, power supply section and a 16x2 LCD for displaying the keys.

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[pushycat]

TRIPLE POWER SUPPLY From USB (EFY Oct 2017)
Nowadays, most portable electronic gadgets are powered by USB adaptors. These adaptors have 5V, 1A to 5V, 2.1A output, which is enough to power low-power circuits of different voltages while testing a prototype. This is done either by using charge pumps or suitable converters. Presented here is the circuit to derive three voltages (3.3V, 5V and 12V) from a USB adaptor. the circuit is built around low-dropout voltage regulator LP2985-3.3 (IC1), monolithic DC-DC converter MC34063A (IC2) a Schottky diode 1N5819 (D1), 22µH inductor (L1) and a few other components.

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[pushycat]

Getting Started With NodeMCU DEVELOPMENT BOARD For IoT (EFY Nov 2017)
Since Internet of Things (IoT) projects are now quite popular, I recently bought a NodeMCU board to try IoT application development. The NodeMCU is an open source development board based on ESP8266EX microcontroller with integrated Wi-Fi transceiver. Uploading programs to NodeMCU from any computer via microUSB port is very easy as it supports several programing languages. This makes NodeMCU a smart choice to play with the IoT. Here I explain how to get started with NodeMCU board using some common tools including Arduino, PuTTY, Lualoder and ESPlorer. NodeMCU board comes in two popular versions: NodeMCU v0.9 with ESP12, and NodeMCU v1.0 with ESP12E (refer Fig. 1). NodeMCU v1.0 is the current version, which is not only breadboard-ready but also has some extra GPIOs

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[pushycat]

INTERFACING MULTIPLE LCDs  With Arduino (EFY Nov 2017)
Here we describe interfacing of three 16x2 LCDs with common data lines to an Arduino Uno board. Four data lines of all the three LCDs are connected to digital pins of the Arduino Uno board but data displayed on each LCD is different. Circuit and working The circuit diagram for interfacing of three LCDs with Arduino is shown in Fig. 1. It is built around popular Arduino Uno board (BOARD1), three 16x2 LCDs (LCD1 through LCD3), three 10-kiloohm resets (VR1 through VR3) and a few other components. The Arduino board is the brain of the circuit, which displays data on the three LCDs simultaneously or individually depending on the requirement.

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[pushycat]

Password-Protected BLUETOOTH REMOTE CONTROL  (EFY Dec 2017)
This password-protected wireless remote control operating at 2.4GHz frequency can be used to control robots, home appliances, machines, etc. Here we have used the secure remote to control a war robot that has three motors, one of which is used to lift objects or weapons such as a cutter (or sword). The article describes configuration of the remote control system and doesn’t cover construction and working of the robot in detail due to paucity of space. The project consists of two pairs of Arduino and Bluetooth HC-05 modules, one of which is used in the transmitter unit and the other in the receiver unit. The Bluetooth module on the transmitter side is configured as master, while the module on the receiver side is configured as slave.

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[pushycat]

Arduino Based Two-wheel self-balancing Segway (EFY Jan 2018)
Segbot,  Segway  and  inverted pendulum—two-wheel  self balancing robots are known by many names. Here we build a two wheel self-balancing robot (Segway) using an MPU-6050 chip. The inertia measuring  MPU-6050  chip  has  six motion sensors—three gyros and three accelerometers—all  integrated  into one breakout board. Here, we only need angular position or gyro of the wheel’s axis. Gyro readings  drift  over  time,  requiring re-calibration  quite  often.  Therefore, to get correct angular position, gyro readings are corrected with the help of a neighboring accelerator. Once the angular position is achieved, traction motors push the cart towards the direction  of  falling.  The  greater  the angle of shift, the greater the speed with which the traction motor pushes the cart. As the angle of shift with vertical position reduces to zero, the speed reduces.  Thus,  the  top  of  the  cart moves like a pendulum, maintaining the balance.

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[pushycat]

Multi function Rechargeable Clock (EFY Jan 2018)
Presented here is a digital clock that also functions as a rechargeable light  lantern  and  a  mobile charger.  The  clock  has  all the basic functions like date time display, alarm and room temperature  display.  It  is powered by a lead-acid battery, which can be recharged through solar power or mains power supply. So the clock never runs out of power. The  clock  is  provided with  a  female  USB  socket, which can be used to charge most of your mobile phones and  gadgets.  Its  dedicated battery  charging  and  load cut-off  circuitry  takes  care of the battery through exact charging  topology  and  prevents  it  from  getting  over charged or under charged.

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[pushycat]

DIY Smart Switch box (EFY Feb 2018)
Most of us leave our battery operated devices like mobile phones,  laptops,  tablets, power  banks  and  modems  plugged into a charger overnight even though these devices, especially smartphones with quick-charge option, take about two hours or less to fully charge. After the device is fully charged, the charger remains idle for more than five hours (say, from 1am to 6am). Since we usually don’t access the Internet at night, modems too are just idling during this time, consuming some power. Here  we  describe  a  power  saver circuit for mobile chargers and modems. It is a simple op-amp-based multipurpose  circuit that provides individual delays for your devices. After a specific amount of  time,  it  automatically turns the devices off.  This  saves power wastage  during  idle time  while  increasing the  operating  life-time of devices.

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[pushycat]

Wireless VU METER (EFY Feb 2018)
V U meter is a standard device that indicates signal level in audio  equipment.  Unlike other  devices,  this  meter doesn’t  require  physical connection between  the audio source and the circuit. The speaker of any audio device produces  magnetic  fields  according to the music. These magnetic fields are sensed by inductor L1 (10µH) and amplified by the pre-amplifier circuit built  around  T1.  The  output  of  the pre-amp circuit is fed to analogue to digital converter (ADC) pin 40 of the AVR microcontroller (IC1). The output voltage of the pre-amp circuit is below 2Vpp and the ADC reference voltage is 2.5V. The microcontroller processes the input signal to drive the bargraph LED (BAR1)  connected  to  Port  C  of  IC1. The louder the music signal, the more the number of LEDs that glow in the bargraph.

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