Top Circuits Page 47
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If the piclist is an any indication the 16f877 seems to be the new favorite hobby microcontroller, a position that used to be occupied by the 16f84/16c84. Compared to is older brethren the 16f877 has much more to offer at around twice the price. As for all....
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This document describes the HSETI PCB. This PCB is a small simple application for the Atmel AT89C2051 microprocessor - a 20 pin 8051 variant, with FLASH (reprogrammable) program memory. The board has just two chips on it, the CPU and a driver/buffer...
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In many applications, a single on/off button switches the power supply on or off. Usually, the system switches off regardless of the processing function or workload the microcontroller or DSP circuit is currently handling. The small circuit in Figure 1 is....
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To maintain content in the event of power loss, many designs that include SRAM require a dedicated device that can automatically switch from a standard power supply to battery operation. Microcontrollers seldom find use in power-switching applications.....
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In many µC applications, a signal conditioner modifies an analog input signal from a sensor and passes it to the µC for processing. The last stage of the signal conditioner is always a device that transforms the signal level to a value acceptable for the....
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Finding out where your microcontroller`s firmware spends most of its time can be a tedious task when you use a conventional in-circuit emulator and breakpoint techniques. Other such tasks include discovering why a state machine doesn`t work as you intended....
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For designers of radar or sonar echo-ranging systems, an echo imitator can ease development and adjustment chores by generating a controllable pulse that's similar to an incoming echo signal. A decade ago, you'd probably use several 555 timers and their....
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OSU8 began as a student project in 1994 to create a simple but functional 8-bit microprocessor, starting with a definition of the architecture to implementation in a Xilinx FPGA chip, and full-custom CMOS implementation. Over a period of about six months,....
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After reading the Mobile Robots Book, written by Joseph L. Jones and Anita M. Flynn, and get the Interactive-C file from ftp://cher.media.mit.edu, I found a very nice S19 downloader written by Randy Sargent. I started to download the pcode to my HC-11 board,....
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A microcontroller, by default, can execute only one program at a time. What do you do if, in a given project, you need to perform more than one operation at a time? Add more microcontrollers to the design? In certain cases it`s unnecessary...
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With the proliferation of dual-voltage architectures and multiprocessor boards, even simple applications can require several processor voltage rails. With each processor having its own power-up and -down requirements, power-rail sequencing and control can....
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Figure 1 shows an efficient and cost-effective frequency counter using an Atmel 89C2051 µC (Reference 1). The design can use any µC of the 8051 family. The circuit counts frequency and sends the count to a PC via the serial port. The signal connects to pin....
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In designing µC-based systems, you often face a situation in which the µC has to respond to an external event happening at an uncertain moment in time. One example is receiving an echo from an object in a pulse-range measuring system. In these situations,....
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Some microcontroller applications usually use too many I/O pins to read keys or onboard switches; in many cases, few pins remain available for other uses. Some alternative ways to read keys yield more free pins. First, consider some ways to effect key....
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The major building blocks for a white-LED driver are an oscillator, a charge pump, and a regulated current source. National Semiconductor (www.national.com) produces a device that contains all these building blocks in the highly integrated LM2791/2 IC. You....
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The traditional frequency multiplier requires many elements: a phase comparator to detect the phase error between the input and the output signals, a lowpass filter to convert the phase error to a dc control signal, a VCO to generate the output, and a....
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RS-232 is the most common serial interface in the PC world. Most RS-232 interfaces communicate with the receiver at a fixed transmission rate, such as 9600 baud. But what happens if the transmitter operates with different transmission rates? Different....
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A project required an inexpensive oscillator whose frequency increased step by step from 200 to 400 Hz and then decreased to 200 Hz. The first step was to design a VCO with a staircase driver. However, this approach entailed at least four ICs and many....
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Driving a bare LCD does not necessarily require specialized interface circuitry or peripherals. This Design Idea describes an alternative drive scheme, which you can easily implement using the general-purpose outputs of a microcontroller. Many....
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The use of public-key-encrypted algorithms within licensed applications can prevent hackers from cracking the licensed algorithms. Moreover, you can use them to disable licensed features that a user doesn`t purchase. Licensing schemes eventually arrive at....
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There is enough of poorly constructed RS232 alike TTL level interfaces (+5volt) , this one generates it`s own +/- 10..11volts as RS232 specs. require , and is able to use very long cables like RS232 can , and protects computer as well , nice in funny....
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A discussion recently on the mp3projects discussion board, about using DRAM memory with small 8-bit processors without DRAM controllers, got me to take up an old idea. I thought it should be possible to hook up a DRAM to a small processor (in this case an....
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The potentiometer portion of a mixed-signal, digitally programmable potentiometer adds variability to an analog circuit, and its digital controls provide programmability. You can use a digital potentiometer in two ways in an analog circuit. You can use it as....
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This is the hardware and source code for an Atmel ATmega8 / MX-614 based UI only TNC. The intent was to provide inexpensive basic TNC functionality for APRS related packet activities. We also have the flexibility to modify the operations of the TNC by....
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This was my second Nixie clock project. I wanted something a little smaller / cheaper / simpler then my rather large B-7971 clock. I will post the design for that one of these days. I was trying to simplify everything. And basically wound up with a one chip....
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A basic circuit of the 89C2051 shown here can be made easily using point-to-point soldering with a universal PCB. Use an ordinary 20-pin socket, do not use a circle-pin socket. D1 is a small dot LED. U2 can be either 7805 or 78L05. U3 is optional for....
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This single sided proto board provides an economical solution for developing and testing the projects around Atmel 20 pin series u-controllers (89Cx051 & AVR)..
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This is my long history the device that controls my home`s night light, air-conditioner,etc. The device is a Miniature Real-time Controller. The circuit uses only three chips, a 89C2051, DS275(or MAX232), and 74LS07 open collector driver. The scheduler for....
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The link shows how to inteface Alphanumeric LCD to 8051 Microcontroller. Liquid Crystal Display also called as LCD is very helpful in providing user interface as well as for debugging purpose. The most common type of LCD controller is HITACHI 44780 which....
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Relays are devices which allow low power circuits to switch a relatively high Current/Voltage ON/OFF. For a relay to operate a suitable pull-in & holding current should be passed through its coil. Generally relay coils are designed to operate from a....
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The Tutorial shows how to interface 7-segment display to a microcontroller. Also explains how do display more than one 7-segment on same data lines using scanning method. 7 Seg displays are are basically 7 LED's. It will be much easier to understand if you....
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This Project Automatic Room Light Controller with Visitor Counter using Microcontroller is a reliable circuit that takes over the task of controlling the room lights as well us counting number of persons/ visitors in the room very accurately. When somebody....
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Use your Symbian OS mobiles to control devices through Bluetooth.
The serial to Bluetooth converter from sparkfun.com is used in this project.
The Microcontroller At89C2051 is used to receive the data from the mobile through bluetooth.
Most of the....
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This project describes a new economical solution of home light control systems. The presented home light control system can be used for different sophisticated home applications. The control system consists of a PC, and control circuitry and the electrical....
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The chip tester verifies the functionality and timing of a variety of 7400 series integrated circuits. Students taking Digital Logic Design Lab, Use these chips often in their laboratory.
The IC to be tested should be placed on the ZIF socket and the....
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This Project is used to indicate the temperature and it is also used as controller. The system will get the temperature from the IC and it will display the temperature over the seven segment display and this temperature was compared with the value stored by....
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This project is an High precision digital thermometer which indicates the temperature on the seven segment display. It has an resolution of 0.06deg.
The 1 wire temperature sensor IC from Maxim semiconductors is used as the sensor. The DS18S20 Digital....
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The Electronic Cash Register (ECR) keeps track of sales transactions quickly and effectively. An abundance of PLUs (Price Look Ups) and department keys accommodate a variety of merchandise items. This means a faster, more accurate check out process and the....
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Now-a-days Electronic voting machines are being used effectively. The confidence of the voter in its flawless working is gradually building up and these machines are thus becoming quite popular throughout the country.
Features of the electronic voting....
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Personal Safes are revolutionary locking storage cases that open with just the touch of your finger. These products are designed as secure storage for medications, jewelry, weapons, documents, and other valuable or potentially harmful items.These utilize....
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The need for a device that can detect and extinguish a fire on its own is long past due. Many house fires originate when someone is either sleeping or not home. With the invention of such a device, people and property can be saved at a much higher rate with....
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Security is a prime concern in our day-today life. Everyone wants to be as much secure as possible. An access control for doors forms a vital link in a security chain. The Microcontroller based Home Security System can be adopted at Home it has various type....
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Infrared interruption counter is a reliable circuit that takes over the task of counting number of interruptions very accurately. When somebody enters into the room, then the Counter is Incremented by one. The total number of Persons inside the Room is....
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This Project REMOTE CONTROLLED SWITCH BOARD is used to switch on/off the Home Appliances by using a standard Remote control. The system is used to switch on/off upto six electrical devices. All the above processes are controlled by the 8 bit Microcontroller....
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Now-a-days every institution needs automation. As a part of college automation, we have decided to do a project Voice Interactive System for College Automation. Our project allows the user to know the students attendance and marks quickly through the....
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This Project Line Following Autonomous Robot is based on 8 bit Microcontroller AT89C2051. This Robot follows the black line which is drawn over the white surface or it follows the white line which is drawn over the black surface. The infrared sensors are....
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This project is used as an electronic private exchange. It has two telephones, which have the intercom facility, and they can be connected to the telephone line. All the functions are controlled by the 8-bit microcontroller AT89C2051 which has an Program....
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Four way Traffic light controller which Has Red, Yellow and Green LEDS. It uses the AT89C2051...
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Power Saving Using Time Operated Electrical Appliance Controlling System is a reliable circuit that takes over the task of switch on/off the electrical devices with respect to time. This project replaces the Manual Switching. It has an Inbuilt Real Time....
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The System is fully controlled by the microcontroller AT89S52. It is a popular 8 bit microcontroller. The circuit consists of four switches, in which two buttons are used to increment and decrement the temperature value and the next button is to edit the....
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This Project is used to control our household electrical devices from any where through the cell phone. The circuit consists of a DTMF tone detector and a powerful 8 bit Microcontroller AT89S52. The microcontroller controls all the system. In this project we....
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This Project is used to control a single phase Motor from any where in the world through the telephone. The circuit consists of a DTMF tone detector and a powerful 8 bit Microcontroller AT89S52. The Microcontroller senses the DTMF signal through the DTMF....
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This project is used to communicate or transmit a text message from one place to another place through wireless. The text message is encrypted by using the Microcontroller and the encrypted message was transmitted through wireless. At the receiver end the....
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The Project Long Range Remote Control can be used to remotely control a number of Electrical or Electronic Gadgets connected to it. Unlike Infra Red remote control, this Project employs FM transmission and Reception, and hence it can be used for....
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RF based Automatic meter reading, or AMR, is the technology of automatically collecting data from energy meter and transferring that data to a central database for billing and/or analyzing. This means that billing can be based on actual consumption rather....
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The convenience of selecting TV channels using your remote and then pointing the same remote to your Computer so that you can control the whole system using the single remote control. The Following functions can be done with PC Remote control...
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The advent of new high-speed technologies and the growing computer capacity provided realistic opportunity for new cost effective technologies and realization of new methods of innovations. This technical improvement together with the need for high....
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Data acquisition is the process by which events in the real world are sampled and translated into machine-readable signals. Data acquisition typically involves sensors, transmitters and other instruments to collect signals, waveforms etc. to be processed and....
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Security is a prime concern in our day-today life. Everyone wants to be as much secure as possible. An access control for doors forms a vital link in a security chain. The microcontroller based Door locker is an access control system that allows only....
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This Project Multi-Pattern Running light is used to generate several designs of Running Lights. We use ten LEDs for display. The designs can be selected by using two switches UP and DOWN. The 8 bit Microcontroller is used to control all the operations. It....
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The board has been initially developed to learn with CAN, so a CAN transceiver is available (IC4). The CAN transceiver comes from Maxim, but some other manufacturers provide some compatible CAN transceivers which can be used. An RS232 transceiver is also....
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The microcontroller used is 0822 zilog encore! 8k series (soic,28pin) as shown on the figure. Is a programmable microcontroller, the functions used are the GPIO and the UART of the chip. GPIO is used on led indicators, and the UART is used for giving and....
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The function generator features two BNC outputs : one for the high speed [1 to 8 MHz] square signal (BNC1) and another for the DDS signal (BNC2). Offset and amplitude can be regulated by two potentiometers : offset in range of +5V to -5V (POT1) and amplitude....
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The DS protocol was designed to provide firmware-based bidirectional host-to-slave inter processor communications for situations in which no hardware solution is available and the host and/or the slave in incapable of tending the interface in real time. The....
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This device provides three channels of 8 bit pulse-width modulation. Output pulse duty cycle ranges from 0 to 255/256 in 255 steps. DACs may be loaded by the DS interface. DAC values may also be copied into the on-chip EERPOM and then automatically be loaded....
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The servo driver is just simply two 4017 decade counters and lots of 0.1" headers. Only populate the A side headers; the B servo bank is optional and will require a few more header pieces. If you received 20 headers, you'll be short two of them. If you....
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Using the software during flight simulation models of planes: REAL-FLIGHT, we first chose a housing of any transmitter empty direct connection potentiometers innings. However this is not good because, first races of the potentiometers are only 90 degrees,....
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We are going to build a START-STOP drive (as commonly found in professional tools), that is a circuit with one switch to run the output (an LED in this case) and one switch to stop it. Nutchip feature two kind of inputs: general purpose and fixed inputs.....
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This circuit is a church bell controller. Basic component is an ATmega32 microcontroller. At the circuit 2 24LC32 eeprom memories is being used, the 1st for internal standard melodies and the 2nd one is for user's compositions. This feature will be provided....
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The demonstration circuit operates in the HM2007's manual mode. This mode uses a simple keypad and digital display to communicate with and program the HM2007 chip. When the circuit is turned on, the HM2007 checks the static RAM. If everything checks out the....
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The microprocessor uses a linear regulator power circuit constructed as shown below, use two MAX666 simply. CPU and A / D converter power supply using A2, RAM and real-time clock power supply with A1. MAX666 output voltage Vo by the VSET (6 feet)..
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High-precision voltage regulator, isolation transformer with the correct wiring and low-pass filter, to further improve the electrical noise immunity source portion. The wiring in Figure 20-48 and 20-49 as shown in FIG. Figure, chokes (Li, Lz) choose an inner..
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The circuit of Figure 1 includes a PIN photodiode that detects individual photons of gamma radiation. The reverse bias on the photodiode sometimes creates a depletion region. When such a photon strikes this depletion region, a small amount of charge....
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Modern high-performance transmitters require accurate monitoring of RF power, because most cellular standards depend on strict power- transmission levels to maintain an effective network. Regulation of transmitted-signal strength also lets you build lower....
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Sending Morse on a rig without a sidetone is not impossible, but is not particularly pleasant either. This battery-powered monitor has been designed to provide an audible indication of keying for those whose rigs lack a CW sidetone. Its sensor wire is....
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RF is just way too cool not to use in your designs. But if you`re a newbie like me it is difficult to successfully build solid RF transmitters and receivers. When I started out I didn`t realize that the larger breadboard I was working off of was causing a....
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No description available...
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This simple circuit is sure to have the police beating a path to your door - however, it has the added advantage of alerting you to their presence even before their footsteps fall on the doormat. The circuit transmits on Medium Wave (this is the small....
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This circuit was designed to detect when a call is incoming in a cellular phone (even when the calling tone of the device is switched-off) by means of a flashing LED.
The device must be placed a few centimeters from the cellular phone, so its sensor coil L1....
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This simple circuit produces a loud trilling noise, if no valid transmitter signal is received. This frequency must correspond with the resonant frequency of the piezo element, otherwise the sound level will be very low...
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This project involves making several modification to an early 1960s era Victoreen CDV700 or CDV600-6B geiger counter. These counters are available on E-Bay for around $50 to $100. The modifications use modern electronic parts to improve the counter`s....
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Old TV tubes are used as cold cathode x-ray emitters in a simple apparatus developed by Bob Templeman of Chicago, Illinois. With selected beam power tubes of the type used in the high voltage section of TV receivers, the intensity is adequate to make x-rays....
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Ions are defined as electrically charged atoms. Positively charged ions have a deficiency of electrons, and negatively charged ions have a surplus of electrons. An ion can also be classified as an atom or molecule with an electrostatic charge. Another....
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This project has not been called a GOLD! detector as this name has been left for the more complex detectors that actually discriminate been gold and other metals. There is an enormous difference between detecting gold and ordinary metals (called base....
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A single chip metal detecor with a range of a few inches. This is useful for decting nails or screws in walls and floors, or for locating buried mains cable...
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The circuit described here is that of a metal detector. The opera- tion of the circuit is based on superheterodyning principle which is commonly used in superhet receivers. The circuit utilises two RF oscillators. The frequencies of both oscillators are....
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This project is offered totally Free for those who are interested in it.
I have tried to make this article as complete as possible, but I will Not
assume any lilability for any "Errors or Omissions" in this article.
If Needed, I will attempt to help you....
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A Very Simple "Beat Frequency Oscillator" type of Metal Detector.
These are about the Simplest of all Metal Detector types,
But still quite useful for many Detecting applications.
And although this one is particularly simple, I find it works very well...
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The circuit described here is that of a metal detector. The opera- tion of the circuit is based on
superheterodyning principle which is commonly used in superhet receivers. The circuit utilises
two RF oscillators. The frequencies of both oscillators are....
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Metal detectors are usually very complicated and it may be consist of very costly components and metal detector DIY circuits are rare. However this metal detector hobby circuit can be constructed by only a few components such as BC548 and an ordinary AM....
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Here's a metal detector circuit that frequencies of the two oscillators are then mixed in similar fashion to BFO, to produce an audible heterodyne. On the surface of it, this design would seem to represent little more than a twinned BFO metal detector...
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This circuit needs a a Faraday shield, which is connected to 0V.To make this one wrap a tin foil around the coil.and connect to 0v.Then you can use this circuit for find metal.Tune your mw radio until whistle sound comes...
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Various embodiments of the BB metal detector have been published, and it has been widely described in the press as a new genre. Instead of using a search and a reference oscillator as with BFO, or Tx and Rx coils as with IB, it uses two transmitters or....
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The circuit incorporates two oscillators, both operating at about 40kHz. The first, IC1a, is a standard CMOS oscillator with its frequency adjustable via VR1. The frequency of the second, IC1b, is highly dependent on the inductance of coil L1, so that its....
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This metal detector circuit needs to be powered using a 9 volts power supply ( DC) or a 9 volts battery .
The C1 capacitor is a variable capacitor with a value of 365 pF , C2 is a 100pF silver mica capacitor , C3 is a 0.05 uF disc capacitor and the C4 is....
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The Meter and other small circuit differences, gives better performance.
On the Schematic, I show Two Possible Coils.
1) The Ferrite Rod, creates an Accurate Pin Point.
But it also has a Very Narrow Detection Field.
2) The Dual Wound "Tesla Coil"....
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The metal detector circuit is shown here that the limits represent the sake of simplicity for a metal detector, but the design works remarkably well. It only uses 40,106 Hex Schmitt inverter IC, a capacitor and a search coil and of course batteries. An....
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These metal detector circuit diagram is based on the TDA0161 monolithic integrated circuit , designed for metallic body detection by detecting the variations in high frequency Eddy current losses. For detecting metals , TDA0161 require an external LC tuned....
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A very simple metal detector electronic project can be designed using a simple 555 timer integrated circuit . As you can see in the schematic circuit , this electronic project requires few external electronic parts .
This circuit detects metal and also....
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A Coil Coupled Operation Metal Detector made from readily obtainable components and using an ordinary medium receiver as a detector. The metal detector shown here may well represent a new genre. At any rate, after some exposure, it is regarded as such by....