Vacuum Tubes Valves
Musical & effects
Yagi Uda Antennas
Metal Detector Circuits
Liquid Sensing Circuits
Light Sensing Circuits
Voltage Detector Circuits
Air-Gas Detection Circuits
Human Sensing Circuits
RF & Radiation
Optical Sensing Circuits
Free Energy Circuits
AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
Digital to Analog
Analog to Digital
Data Bus Circuits
Voltage to Pulse
Current to Voltage
Frequency to Voltage
RF Converter Circuits
Sine to Square Wave
Voltage to Current
voltage to frequency
Period to Voltage
Video Wall circuits
TV Video Circuits
Motor Control Circuits
8051 / 8052
PCB CAD Software
Car bike Circuits
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
DIY HV Variable Cap
DIY PMA alternator
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Microcontroller`s DAC provides code analysis
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 and where your code goes during real-time operation or during an error condition. Classic...
Microprocessor, linear potentiometer deliver echo pulses
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 associated RC circuits to design an echo imitator. As Figure 1 shows, today's version uses...
OSU8 Microprocessor Project (1994)
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, the project came together and was, more or less, a success. The Xilinx-based hardware...
Microcontroller becomes multifunctional
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.
Microcontroller directs supply sequencing and control
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 become a complex task. The challenge for power-supply designers is to consider each...
Microcontroller makes effective frequency counter
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 3.4 of the µC. The TTL-compatible output of the µC drives the 1488, which converts the...
One microcontroller serves multiple external interrupts
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, you would usually use an external interrupt. Unfortunately, low-end, small, inexpensive µCs...
Key-reading circuit saves I/O pins
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 reading. Table 1 presents a comparison of four methods with references to circuit...
LED driver provides oscillator for microcontroller
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 usually use white-LED drivers in tandem with cellular baseband controllers or...
µC-based circuit performs frequency multiplication
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 divider to set up the multiple ratio. The circuit in Figure 1 uses a different approach to...
µC detects transmission rate of RS-232 interface
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 transmission rates require the receiver to detect the rate and adjust the software to the new...
µC forms FM oscillator
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 discrete components. An alternative method (Figure 1) requires only one 16-pin µC (an...
Embedded processor directly drives LCD
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 embedded-system applications need to interact with a user by displaying simple numeric or alphanumeric...
Encrypted routines impede hackers, protect licenses
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 some critical decision point at which an algorithm decides whether the user is entitled to...
Homebuilt RS232 LCD Interface
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 environment like inside a "MP3 in car" setup. There is plenty of ready RS232-Lcd controllers 4...
Digital potentiometer programs and stabilizes voltage
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 a two-terminal variable resistance, or rheostat, or as a three-terminal resistive...
ATmega-TNC. An ATmega8 based UI TNC
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 modifying the source code to add features or modify existing functions.
An ATmega48 based Nixie Clock
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 solution, ... the micro itself does just about everything.
Interfacing Alphanumeric LCD To Microcontroller
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 provides a simple interface between the controller & an LCD. These LCD's are very simple to...
Interfacing Relay To Microcontroller
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 particular voltage often its 5V or 12V. The function of relay driver circuit is to provide the...
Interfacing seven segment to microcontroller
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 first read Interfacing LED's to Microcontroller.
Auto light Controller and Visitor Counter
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 enters into the room then the counter is incremented by one and the light in the room will...
Bluetooth for Symbian OS Mobiles
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 Nokia smartphones can be used in this project.
PC home light control system
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 devices.
Digital IC Tester for 74 series
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 Microcontroller prompts the user to enter the IC number of the chip to be tested. After...
Digital Temperature Controller
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 the user and if the Room temperature goes beyond the Preset temperature then an alarm is...
High Precision Temperature Indicator
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 Thermometer provides 9bit centigrade temperature measurements and has an alarm function with...
Cash Register circuit
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 ability to manage a wider variety of goods and services more efficiently. And with...
Voting Machine circuit
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 machine include avoidance of invalid votes and reduction of counting time and the consequent...
FingerPrint Security circuit
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 fingerprint recognition technology to allow access to only those whose fingerprints you...
Fighting Robot circuit
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 relatively minimal damage caused by the fire. Our task as electrical engineers was to...
Home Security System with microcontroller
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 of Sensors. In our Project we have magnetic sensors, Wire Loop sensors, Fire sensors. The...
Arduino Projects and Circuits
PIC Microcontroller Circuits
AVR 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...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity