Vacuum Tubes Valves
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AC to DC & DC to DC
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Data Bus Circuits
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Current to Voltage
Frequency to Voltage
RF Converter Circuits
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voltage to frequency
Period to Voltage
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8051 / 8052
PCB CAD Software
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H Bridge Circuit
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4 Band Resistor
5 Band resistor
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AVR Microcontroller Circuits
AVR Microcontroller Circuits
RFID Based Security System with AT89S52
This project aimed to develop a wireless system to detect and allow only the authorized persons. The system was based on Radio Frequency Identification (RFID) technology and consists of a passive RFID tag. The passive micro transponder tag collects power from the 125 KHz magnetic field generated by the base station, gathers information about the...
Remote Controlled Digital Clock with AT89C2051
This Project is made up with AT89C2051 and the RTC DS1307. It has a large Seven segment display. The standard remote control is used to change the Time.
Remote Control Through Internetwith AT89S52
This project entitled Remote Control Through Internet allows us to monitor, control and automate our home from remote locations. In existing system home automation and security are separate systems working independently. Also in existing system if any one of the sensors goes abnormal the user is not immediately informed about the status, since...
PC Based Robot with AT89C2051
The advent of new high-speed technology and the growing computer capacity provided realistic opportunity for new robot controls and realization of new methods of control theory. This technical improvement together with the need for high performance robots created faster, more accurate and more intelligent robots using new robots control devices,...
Digital code Lock with AT89C2051
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 digital lock for Doors is an access control system that allows only authorized persons to access a restricted area. The system is fully controlled by the...
AVR Microcontroller Digital Clock with ATtiny2313
Usually we see Digital clock on LCD or 7 segmen. But, this AVR Digital Clock which is designed by Ficara Emilio displayed on Oscilloscope. The project use ATtiny 2313 as the main controller. What an interesting microcontroller project. Source code and schematic available for download..
Wireless Coupled Scanning Voltmeter (ATMega8)
A 10 bit scanning voltmeter with a Minimum Mass Wireless Coupler, based on the ATMega8.Range to the Minimum Mass Base Unit is 10 to 15 cm. If the voltmeter is battery operated, it can be floated from ground. This project is very simple physically, intended to demonstrate how easily the Minimum Mass RF Link can be added to a project. The circuit...
Wireless Coupler Terminal Interface
The purpose of the terminal interface is to allow my computer to communicate with Minimum Mass Wireless Coupler equipped devices using a terminal emulator program. Consequently, the Base Unit is basically an RS-232 interface and Minimum Mass Wireless Coupler. The Base Unit is the larger enclosure in Photo 1. The RS-232 interface to the...
Here's a way to get a short range bidirectional RF (Radio Frequency) channel on a microcontroller, using the controller's tristatable I/O pins and on-chip comparator with a few passive components. The range with the firmware and simple I came up with for Atmel AVR controllers allows for low error rate communications over 10 to 15 cm using a 5.5...
Maxim's MAX038 function generator chip is capable of producing nearly constant amplitude sine, square, and triangle waves with a low output impedance, from a very low frequency to more than 20 MHz. Basically, a function generator on a chip. Here is a function/sweep generator that uses the MAX038 chip. The design described on these pages are not...
Wide Basic for ATtiny2313
This firmware is intended to run on an Atmel ATtiny2313 operating from a 4, 8, 10, 16, or 20 MHz clock or an AT90S2313 operating from a 4 MHz clock. As far as I have been able to determine, the ATtiny2313 and AT90S2313 versions are interchangeable, and the only difference is that they were assembled using different include files. When connected...
Digital Telemetry with ATMega8
The ATmega8 microcontroller-based Low-Cost Telemetry Device (LTD) is an efficient telemetry keyer. The LTD measures the voltage levels of up to four analog channels via its on-chip 10-bit ADC, converts the measurements to numbers, and then sends the data in Morse code to an external transmitter and to an attached RS-232 terminal. It can be set...
RF Field Strength meter
As I used this probe last nigh to determine if a 384 MHz oscillator was really working or not, I remembered email I received a while ago, asking how to make a field strength indicator without the microcontroller. Thus this page. If you want the auto zero version, which is this circuit with an auto-zero integrated circuit, use the circuit shown...
Ponyprog for AVR
On board the AVRs that can be programmed are those in the schematic. For other members of AVR family or the rest programmable ICs that Ponyprog can program, there is the J1 connector (CON10) which allows expanding the programmer's hardware. See Ponyprog's site for other's ICs Ponyprog circuits. The JUMP1 jumper is there to connect the crystal's...
EEprom programmer for ATMEL 89 Series
The EEprom programmer software supports the following devices 28C16 28C256 28C17 29C256 28C64. Diode D1 and resistor R1 provide the VDD isolation when programming the 24 pin devices. The jumper J3 must be shorted for 24 pin devices, and open circuit for 28 pin device programming. Following EEPROMs are pin compatible with their EPROMs version,
PCB Exposure Box with Countdown timer (ATMEGA8)
Four blacklight lamps, 15W each, emit radiation at the region of UVA, with a peak around 350nm where the thin surface above the copper of the photosensitive board, is... sensitive. The lamps are taken by two and are connected in series thus shaping two similar modules. Each module has its own ballast and can be connected to 220V AC via a relay....
89Sxx Development Board
The hardware block is shown in Figure 1. The MCU is 89Sxx microcontroller. And the complete hardware schematic is shown in Figure 2. Port1 is used as data-bus for LCD (4-bit interface, PCB lay-out for 16x2 character with backlight), on-board tact switch and connection for In System Programming (ISP) Port0 and Port2 as general purpose IO, are...
Programable Board with 32K RAM
While there is a list of features that I would like to add (32k EEPROM support, line numbers to 65,535, more stack space, strings, arrays, 16 bit variables and arithmatic, possibly named variables and REM statements for starters), I have not been able to dedicate much time to this project. You are invited to make enhancements, and I sure would...
This firmware is intended to run on Atmel ATmega163 (499 bytes for program memory) or AT90S8515 (298 Bytes for program memory). Communications with the terminal is via RS-232 at 9600 baud. Use 8 data bits, 1 stop bit, and no parity. The RXD pin and TXD pin should be connected to an inverting RS-232 interface. The Maxim MAX-232 and the discreet...
AVR Microcontrolled PLL FM Transmitter
An LMX1601 Phase locked loop, a discreet FET VCO, and an AVR micro controller combine to make a stable, easy to use monophonic FM transmitter that includes a an audio activated switch that turns the transmitter on only when its being used. The common characteristic of all of the previous low power FM transmitters I've built over the decades, is...
Serial Programmer for AVR microprocessors
Atmel described a simple programmer based on the AT90S1200 (NOT the AT90S1200A) controller in their application note, AVR910 (a modification to use the AT90S2313 is also given below).The circuit is so small and simple, I was able to put two of them together without using a printed circuit board, taking only about an hour to assemble each one....
Data Transfer interface
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 only specialized hardware required is two bidirectional I/O ports on each chip...
RF data link and remote control
This section describes an experimental low power, low bandwidth data signaling system that was initially made to operate at 55 MHz (television channel 2 in the U.S.). Before operating a radio transmitter, find out what kind of transmitter operation, if any, is permitted in your locality. Radio transmitter operation is a serious legal matter....
This basically the frequency meter section of the frequency meter/pulse generator based on the AT90S2313 described elsewhere on this site, combined with the 100 MHz RF interface described in the page about the RS-232 to 100 MHz RF desktop channel adapter. Built and align this is the same manner as the 100 MHz RF desktop channel adapter. The...
AVR Inductance / Capacitance meter
This instrument requires two precision components: A precision capacitor and a precision inductor. You only need to start with one precision component, either the reference capacitor or the reference inductor, and using this meter, you can select or adjust the other precision component. Calculates and displays L and C from oscillation frequency...
AVR Inductance / Capacitance meter II
If this picture (above) looks a lot like the Pretty Good LC Meter also on this web site, that's because its the same meter, but with some significant improvements. At this point, its a good idea to read the Pretty Good LC Meter page because the rest of this page is based upon the Pretty Good LC Meter, and the Pretty Good LC Meter page explains...
Digital Sine Wave Oscillator
If found myself in need of a 1 KHz signal source for an experiments. My function/sweep generator was needed as a pulse generator for the same experiment, so I went though my junk box, looking for circuits from long ago that might fill the need, but found nothing useful. I had a board with an AT90S8515 and an 8 bit resistor ladder network on it,...
AVR Frequency Meter
This is design for a frequency meter based on AVR microcontrollers. Maximum input frequency is specified to be 30 MHz in the multi-chip configuration, and in single-chip configuration, there are both 5 MHz and 10 Mhz versions operating with 10 and 20 MHz crystals, respectively. All versions have 9 1/2 digit resolution. I have used multi-chip...
Frequency Meter and Pulse Generator with AT902313
Power input is to a 7805 5 volt regulator. A pair of LEDs is connected between the 5 volt supply and ground, with current limiting resistors in series and one pin on the AT90S2313 shunts the current through one LED or the other. When one LED is on, the device is "ready", that is not generating pulses on the output and not measuring input...
serial interface with 2X16 LCD display
The 040904C version of the code has a larger UART receive buffer and supports two pushbuttons that send either and ASCII "R" ($52) or an ASCII carriage Something to keep in mind when using AVR controllers that support 16 bit addressing(specifically, the ATTINY2313/AT90S2313 only has an 8 bit stack pointer, while some others have 16 bit stack...
G1216B1N000 dot graphics display
A serial interface and bias supply for the Seiko-Epson G1216N000 using an AT90S2313 because there just aren't enough applications examples for this display on the web. The display is a pretty old transflective gray mode TN LCD design with ok, but not great contrast. Its contrast is better than the screen shot above. The display's saving grace is...
Wireless Coupled Frequency Meter
A 0 to 2 MHz ferquency meter with a Minimum Mass Wireless Coupler, based on the ATMega8.Range to the Minimum Mass Base Unit is 10 to 15 cm. Since the frequency meter is battery operated, it can be floated from ground, making life in and around the test bench a lot simpler. No need to connect it to the computer or LCD display - just turn in on...
Arduino Projects and Circuits
PIC Microcontroller Circuits
Microcontroller Programmer Circuits
68HC11 Microcontroller Circuits
8051 / 8052 Microcontroller Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial