Electronic Circuits and Tutorials
Electronics Schematics - M

Microprocessor Circuits

Cornell University ECE 4760 Designing with Microcontrollers Final Projects - Students in ECE 4760 at Cornell University were given the responsibility of choosing, designing and building a project using Atmel Mega644 microcontrollers. Projects this year include video object tracking, acoustic GPS navigator, and an automated rock band guitar player, as well as musical instruments and scientific devices. During the last 5 weeks of the semester in ECE 4760, Microcontroller Design, students have to combine sensors, actuators, microcontrollers, and mathematical techniques to build something.

µC implements Pushbutton Light Dimmers: 06/18/98 EDN-Design Ideas

10 Tricks for Interfacing to the PIC16C508:

101 AT Keyboard to ASCII Decoder: The Host to Keyboard Protocol is initiated by taking the KBD data line low. However to prevent the keyboard from sending data at the same Time that you attempt to send the keyboard data, it is common to take the KBD Clock line low for more than 60us. This is more than one bit length. Then the KBD data line is taken low, while the KBD clock line is released.

12C508 Smart Lock: The base sends a data sequence (the password) which is recognized by the key. The key checks the sequence and -if it recognizes it -sends to the base another data sequence, as an answer to the password. At the Time when the base gets a correct answer (which means that the key has been introduced), the relay is put into action, and it can command a number of consumers.

2 Wire LCD Interface using PIC16CF84:

27c801 EPROM Programmer Project:

40+ MHz 5 Digit Frequency Counter With An AVR 2313:

50 MHz Frequency Counter, Voltage Meter & SWR/PWR indicator:

68HC11 Based RDS Decoder:

68HC11 Function Generator:

68HC11 Instruction halts External RC Clock: 04/27/95 EDN-Design Ideas

68HC11 Stepper Motor Control:

68HC11 Stepper Motor Control:

68HC11 Synthesizes Accurate Sine Wave: 09/02/96 EDN-Design Ideas

8051 Development System Circuit Board:

8051 Development System Circuit Board:

8088 Maximum Mode SBC:

About PIC Microcontrollers:

AC Lamp Dimmer for Basic Stamp:

AC Vias Can Improve Decoupling: 04/28/03 Electronic Design - Ideas for Design / Good decoupling is nearly always essential in a world of mixed-signal designs that exhibit increasing speed, performance, and component density. There are cases, though, where proper decoupling is absolutely critical if the circuit is to deliver its..

Acceleration Monitor using ADXL202 and AVR AFSK 1200 Modem Based on PIC16C620:

Analog input circuit serves any microcontroller: 12/20/2001 EDN - Design Ideas / The simple ADC in Figure 1 is perfect for getting analog signals into a purely digital microcontroller. Using just five surface-mount parts, you can assemble it for less than 50 cents (1000), which is approximately half the cost of a single-chip-ADC approach in the same volume. Moreover, this design takes only one pin from the microcontroller to operate. .

Analog to Digital Conversion Notes for PIC Processor:

AT89C2051 / 4051 Driving Dot LED:

AT89C2051 / 4051 Easy Downloader:

AT89C2051 / 4051connecting Dumb Terminal:

AT89C2051 / 4051scanning 7 Segment Display & Keypad:

AT89C2051 / 4051Stepper Motor Interface:

AT89C2051 Digital Thermometer & Clock:

AT89C2051 Line Follower Robot:

AT89C2051 Night Light Saver:

AT89C2051 Real Time Controller:

AT89C2051 Serial Coms to LED Driver:

AT89C51 / 52 / 55 Easy Downloader:

AT90S8515 Experimenter Board:

Atmel 8051 Flash Based Microcontroller Programmer:

Atmel 89C Series Flash Microcontroller Programmer:

Atmel AVR Programmer:

AVR Based Serial Port IR Receiver:

AVR Beacon Super Keyer:

AVR Digital Voltmeter:

AVR Frequency Counter:

AVR microcontroller makes improved motor controller: 10/17/2002  EDN - Design Ideas / The circuit in Figure 1 provides a novel method of reading the pulse train using an Atmel (www.atmel.com) AVR processor, from a typical radio-controlled receiver, and to determine the velocity of a motor. To capture the pulse train from a typical receiver, you need an external interrupt that triggers based on a rising and a falling edge..

AVR Signal Generator:

Basic Stamp Computer Eases Prototyping hassles: 04/09/98 EDN-Design Ideas

Basic Stamp Interface Circuits:

Basic Stamp Lightning Activity Monitor:

BASIC Stamp Thermoelectric Cooler:

Build a PIC Controlled DDS VFO, 0 to 6 MHz:

C 52 EVB Robot Controller:

Circuit Controls Two LEDs With One Microcontroller Port Pin : 04/01/02 Electronic Design - Ideas for Design /Microcontroller port pins can typically be driven either high or low, or else be put into an "input" or high-impedance state. This circuit uses the three states to drive two separate LEDs with one port pin. This can be very useful when there are no...  

Circuit provides watchdog for microcontrollers: 12/26/2002  EDN - Design Ideas / The watchdog circuit in Figure 1 uses a single NAND Schmitt-trigger IC. The circuit is more cost-effective than dedicated, commercially available watchdog ICs. The circuit generates an active-high reset signal upon power-up and remains in a low state as long as the control input receives pulses. Whenever the pulsing at the control input stops, whether the circuit is in a high or a low state, th....

Closed Caption Decoder: This is a closed-caption decoder with serial output, based on a PIC16C71, an Élantec EL4581C sync separator, and an LM393 dual comparator (for data slicing with automatic threshold).

Combination Lock (PIC16F84):

Connecting LED to PIC Micro I/O Pins:

Connecting PIC12C508 8 to 93AA46 Serial Eprom:

Controller Provides Multiple Alarm Driver Formats: 01/15/98 EDN-Design Ideas

Digital signal controls sine generator: 05/15/03  EDN-Design Ideas / The circuit of Figure 1 produces an accurate, variable-frequency sine wave for use as a general-purpose reference signal. It includes an eighth-order elliptic, switched-capacitor lowpass filter, IC3, which uses a 100-kHz square-wave clock signal that microcontroller IC2 generates. (Any other convenient square-wave source is also acceptable...

DS1820 Arbiter V2.00 Schematic:

DS1820 Temperature Sensor Readout Unit:

Dual PIC16C84 Prototype Board:

Electronic Door Codelock With PIC16F84:

Electronic Door Codelock:

Embedded System to Send E Mails (small TCP/IP Stack):

EZ80 Single Board Computer Schematic (Z80):

Freign Vocabulary Recollector:

FSK Modem With PIC16C84:

Galvanic Decoupling of I2C Bus:

Measure Fast Video-Signal Amplitude

Generate Video Signals:

Giant Money Counter (PIC16F876):

GPS LCD Display Project:

GPS Repeater:

Graphic LCD Interface:

High Efficiency Halogen Bike Light Dimmer: This circuit uses a PIC16F84 microcontroller with some software to control20-Watt12V DC halogen lamp

IC16F876 Datalogger:

Infra/radio Remote Control Transmitter/receiver With PIC:

Interfacing DRAM to AT90S8515:

Interfacing Piezo Elements to a Microcontroller:

Interfacing S 7800to PIC16F877:

Interfacing thePIC16C508:

JDM Programmer:

KD7LMO Micro Beacon (PIC18F252):

Key reading circuit saves I/O pins: 03/06/03  EDN-Design Ideas / 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 configurations (figures 1, 2, 3, and 4)

Kodak DC 20 Camera Interface (PIC12C509):

Kodak DC 20 Camera Interface (PIC16F84):

LCD Serial Terminal:

LCD to PIC16C54 Schematic:

Low Cost Digital Thermometer Uses SingleChip Microcontroller : 02/18/02 Electronic Design - Ideas for Design / In many applications, the ability to read and display temperature is either desirable or an absolute requirement. Some of these applications include temperature probes, thermostats, CPU monitors, and process-control equipment. The ...  

Low Voltage Reset operates Below 2.7V: 03/26/98 EDN-Design Ideas

Mains Clock Controller using AT89C2051:

Make a DAC with a microcontroller's PWM timer: 09/05/2002  EDN - Design Ideas / Many embedded-microcontroller applications require generation of analog signals. An integrated or stand-alone DAC fills the role. However, you can often use PWM signals for generating the required analog signals. You can use PWM signals to create both dc and ac analog signals. This Design Idea shows how to use a PWM timer to simultaneously create a sinusoid, a ramp, and a dc voltage..

Make noise with a PIC : 08/07/03  EDN-Design Ideas / Building a stable noise generator for audio-frequency purposes requires only a few components. The circuit in Figure 1 relies on linear-feedback shift registers and some simple software. An eight-pin Microchip (www.microchip.com) PIC12C508 controller (IC2) with a short program generates pseudorandom noise at its output pin, GP0....

Microchip PIC ICD (in Circuit Debugger):

Microchip PIC ICSP implementation:

Microcontroller Becomes Multifunctional: 10/25/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Microcontroller directs supply sequencing and control: 05/29/03  EDN-Design Ideas / 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 processor's timing and voltage requirements.

Microcontroller discerns addresses in RS 485 systems: 11/08/2001 EDN - Design Ideas / One of the many benefits of using the RS-485 data-interface system, unlike the RS-232 system, is its ability to implement multidrop networks. Such networks usually carry 9-bit data words, in which the ninth (parity) bit identifies each word as address or data. When using small microcontrollers without a hardware UART, such as IC1 in Figure 1, designers must decide whether to add an exte... .

Microcontroller emulates numerically controlled oscillator: 02/21/2002  EDN - Design Ideas /   Microcontrollers commonly add intelligence or digital functions to products, but they can also provide a variety of analog signals. An 18-pin PIC 16C54 microcontroller, combined with an inexpensive, 8-bit DAC and a simple lowpass filter, can generate sine waves from dc to approximately 50 kHz with a tuning resolution of 24 bits.

Microcontroller Interface for 5KWatt Microwave oven:

Microcontroller Makes Effective Frequency Counter: 11/23/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Microcontroller Multi Channel Light Dimmer:

Microcontroller Multi Channel Light Dimmer: The project is a microprocessor-controlled multiple channel lighting dimmer, that could be used in theatrical and other applications. The device will accept input from a wide range of interfaces: RS232 input, DMX512 (theatrical lighting standard) or RS485, or a Musical Instrument Digital Interface (MIDI). The device will control a number of lamps by using some form of AC power control. The firmware in the microcontroller will handle all functions, from decoding the protocol on either of the input interfaces through to Timing the firing of power triacs for the output.

Microcontroller provides SRAM battery backup: 06/26/03  EDN-Design Ideas / 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. Because microcontrollers typically operate from the primary power supply, they stop execution if that supply drops, thereby making it impossible....

Microcontroller selects minimum/maximum value: 09/20/2001 EDN - Design Ideas / Microcontroller-based systems for measurement, sensor-data processing, or control, sometimes require you to determine a maximum or minimum data value. For example, in an object-detection system, such as a radar or sonar system, the microcontrolle.

Microcontroller Sensor and Actuator Interfaces:

Microcontroller Watches, Controls AC Power: 06/22/95 EDN-Design Ideas circuit allows an isolated microcontroller to both sense and control ac power to an externally plugged-in device

Microprocessor RS 232 Reset:

Microprocessor RS232 Reset:

MiniLOGGER V1.0:

Mk2 PC Based EPROM Programmer:

MMC to PIC16F876 Circuit Diagram:

Multi Chip Programmer:

Multimedia Electronic Crib: microcontroller based light controller which generates sequence of day-night with light fading, optional serial control interface, based on 87C51

Network Time Protocol AVR Clock:

Night Light Saver (PIC12C508):

Nixie Clock (PIC16F876):

No Parts PIC Micro Programmer:

One Microcontroller Serves Multiple External Interrupts: 02/01/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Optical Sensor using PIC12C508:

PIC 18 Programmer (PIC18F458, PIC18F452, PIC18C252, PIC16C745, PIC18F6620, PIC18F6720):

PIC 5x7 Display:

PIC Based Keyboard Emulator:

PIC Based Motor Controller:

PIC Based Packet Radio Encoder:

PIC Based Robot:

PIC Based Web Server:

PIC Controlled DDS VFO, 0 to 6 MHz:

PIC Controlled DDS VFO, 0 to 6 MHz:

PIC Demo Board:


PIC LCD and Keypad Driver:

PIC Logic Probe With Pulser:

PIC Micro LED Projects:

PIC Micro Multiple Servo Motor Interface:

PIC Micro Programmer:

PIC Microcontroller Servo Motor Interface:

PIC Programmer 2:

PIC Programmer for Serial Port:

PIC Programmer: to download programs into PIC microprocessors.

PIC Programmers for Parallel Port:

PIC Project #1   RS232 to I2C Interface:

PIC Tetris Game:

PIC Tock Video Clock:

PIC X1 Schematic (PIC16F877):

PIC12C508 Night Light Saver:

PIC12C508 Phase Controller for 2kW heater:

PIC12C509 Gym Timer:

PIC12C509 Logic gate Replacement for Nitrogen Filler:

PIC16C505 IR / Wireless Remote Control:

PIC16C63 MIDI Controlled Light Dimmer:

PIC16C84 VT 52 Emulator for Linux:

PIC16C84 VT 52 Emulator for Linux:

PIC16F84 Based Morse Code Reader:

PIC16F84 Countdown timer:

PIC16F84 CW Decoder:

PIC16F84 Debugging Terminal:

PIC16F84 LED Chaser:

PIC16F84 Line Following Robot:

PIC16F84 Line Following Robot:

PIC16F84 Miniature Real Time Controller:

PIC16F84 Programmer #2:

PIC16F84 Programmer:

PIC16F84 Pulse Monitor With Date/time Output (ZIP):

PIC16F84 Serial I / O Expander With PicBasic:

Christmas Lights:

PIC16F84 Stepper Motor Controller:

PIC16F84 tone Generator (6 Bit):

PIC16F84 tone Generator With Source Code:

PIC16F84 tone Generator:

PIC16F84 TrIAC / IGBT Brightness Phase Controller:

PIC16F84 Ultrasonic Range Finder Project:

PIC16F84 Web Server:

PIC16F873 Digital Clock:

PIC16F873 Remote Display:

PIC16F873 ultrasonic Range Meter:

PIC16F877 Programmer and Development System:

PIC16F877 to IDE Interface:

PIC18 Schematic:

PIC18F252 Bootloader Schematics:

PICADC a Free, PIC Based "intelligent" a / D Converter:

PicCon   Hidden Radio Transmitter Controller:

PICDIM Application Note: This is a lamp dimmer design based on PIC12C508 microcontroller.

PicoWeb V5.1 (AT90S8515) tiny Web Server:

Picxie 2 8x8 Animated LED Signboard:


POCSAG Encoder/decoder:

Programmable Clock Oscillator: PIC-Tock video clock using a PIC16C61

Programmer for the 68HC705C8 MicroController:

Programmer PIC16F84,12C50x and EEPROM 24Cxx:

Propellor Clock (PIC16F84):

RDS Encoder   Digital Part:

BTc Sound Encoder 3.0 Software

Remote Control Encoder/decoder With PIC16C620 & PIC12C508:

Remote Control for Raymarine ST4000 Autopilot:

Rotating Sprocket Wheel Generator (PIC16F84):

RS 485 RPT Schematic:

RS485 Like Multi Drop Bus With half Duplex Serial Protocol:

RS485 Version of the SAB80C535 Microcontrollerboard:

ScanMate Audio Activated Recorded:

Scenix (and PIC) Programmer:

Ser Key 10 Key Serial Keypad Encoder:

Serial Comms to LED Driver:

Serial Port Break Reset Circuit:

Serial to Parallel Converter using the AT89C2051:

Speaking Clock using PIC & ISD Device: SpeClo was designed and built to be used by the blind. Its purpose is to provide a relatively easy way for ascertaining the Time of day by whistling, and can be configured to speak English or German!

Speaking Doorbell: SpeDoB was designed and built to gain experience with the PIC microcontroller. This doorbell uses a speech recorder integrated circuit (ISD series) to play back3 pre-recorded "theres someone knocking on the door" messages. Its a very easy and simple project to build, ideal for beginners!

Speech Recognition using HM2007:

ST6 Microcontroller & TrIACs on Mains: includes dimmer circuit example

Improved Universal Motor Driver

Talking PIC   Based on SP0256:

Talking YODProject (PIC16C84):

Temperature Controlled Based on AT89CX051:

Temperature Monitor/controller: AVR 2313 / DS1621:

Temperature Sensitive Oscillator: Temperature controlled based on AT89CX051

Ten Tricks for Interfacing to thePIC16C508:

Thermistors and a Microcontroller Simplify Anemometer Design : 10/14/02 Electronic Design - Ideas for Design / Typically, air flow is measured with a hot-wire anemometer. Here's an alternative version of that concept using two thin-film platinum resistance temperature detectors. A high-performance mixed-signal microcontroller can make the measurement and drive...  

Thermoelectric Controller (scriptable Thermometer):

Tony Nixons Pocket Programmer (PIC):

Two Wire LCD Interface using PIC16CF84:

Use Four External Interrupts Through One 8051 Input : 05/13/02 Electronic Design - Ideas for Design / The 8051-compatible microcontrollers are equipped with up to two inputs that may be used as general-purpose interrupts. A simple way to increase the number of interrupt inputs is shown in the figure. The...  

I2C / SPI LCD Interface

Voice Recording and Message Retrieval System:

Way Small Web Server:


Wisp628 ISP Microchip PIC Programmer:

World's Smallest PIC Programmer:

WWWpic2   a Web Server in a PIC:

Zilog Z80 thermostat Embedded Web Server:

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