Here is a very simple project of controlling a small DC-motor (taken from an old personal cassette player) with ATmega8. The ATmega8 is having three PWM channels, out of which two are used here. PWM waveforms are fed to MOSFET (RFD3055) H-bridge. Here, direction is controlled using a two-position toggle switch and speed of the motor is controlled by two push-buttons, one for increasing the speed and other for reducing.
Simple PWM DC motor control using MOSFET H-Bridge with AVR ATmega8 - [Link]
dangerousprototypes.com writes: [via]
Here’s a good tutorial from ExtremeElectronics.co.in explaining the types of stepper motors, their uses, and how to interface them with an AVR microcontroller.
It includes the xstepper code library for use with the AVR Atmega16, and demonstrates how to interface the MCU and the motor using a ULN2003A high-voltage high-current Darlington transistor array.
This tutorial is comprehensive and provides beginners with the theory and sample code to get started with a simple stepper motor project.
Stepper motor tutorial – [Link]
rbw writes – [via]
Pulse Width Modulation (PWM) is a technique widely used in modern switching circuit to control the amount of power given to the electrical device. This method simply switches ON and OFF the power supplied to the electrical device rapidly. The average amount of energy received by the electrical device is corresponding to the ON and OFF period (duty cycle); therefore by varying the ON period i.e. longer or shorter, we could easily control the amount of energy received by the electrical device. The Light Emitting Diode (LED) will respond to this pulse by dimming or brighten its light while the electrical motor will respond to this pulse by turning its rotor slow or fast.
Working with Atmel AVR Microcontroller Basic Pulse Width Modulation (PWM) - [Link]
Using an AVR as an RFID tag, Beth writes… [via]
Last time, I posted an ultra-simple “from scratch” RFID reader, which uses no application-specific components: just a Propeller microcontroller and a few passive components. This time, I tried the opposite: building an RFID tag using no application-specific parts.
Well, my solution is full of dirty tricks, but the results aren’t half bad. I used an Atmel AVR microcontroller (the ATtiny85) and a coil. That’s it. You can optionally add a couple of capacitors to improve performance with some types of coils, but with this method it’s possible to build a working RFID tag just by soldering a small inductor to an AVR chip
Using an AVR as an RFID tag - [Link]
We released the 28 Pin AVR Development Board back in 2008 and since then it has gone through many iterations. This week we release version 1.6 which adds 4 improvements. These improvements were based on customer feedback and we are very grateful for the feedback. Please keep it coming.
28 Pin AVR Development Board – Version 1.6 – [Link]
Jaroslaw Lupinski designed the Senpai (Shield for Extra Nimble Programming of Arduino) shield, to make it easy to program AVR microcontrollers using an Arduino: [via]
If you want to take your device to the next level, you’ll need to program a bare AVR chip to run the code you’ve developed. If you want to build around the ATMega328 chip (the same chip that’s inside the Arduino), you can even program the bare chip with the same code as the Arduino sketch. A great sketch has been written by an Arduino user that lets you turn your Arduino into an AVR programmer. It’s great if you just need to program one chip and be done with it, but sometimes you want to develop code while a chip is socketed on a board, to program surface mount components, or to program lots of chips in a short amount of time. Using the shield I developed, you can use the ZIF socket to quickly swap out chips to be programmed (it supports 3 device families), or use the Atmel standard ICSP protocol to program chips that are already in-circuit with the ICSP header.
Program AVR microcontrollers using your Arduino and the Senpai shield – [Link]
AVR Datalogger Zero is an AVR development board that is designed to experience data loggers. This board is designed by Chris Kern. It is mainly intended to help develop experience with technology useful for building data loggers, specifically sd card storage and ethernet connectivity. The board is designed for low power operation. Most onboard systems are powered by a 3.3v switching regulator.
AVR Datalogger Zero – [Link]
This project use a PC for GUI display and AVR Based data converter board. The circuit is built with the ATmega8. The GUI programming with Visual Basic to receive data from ATMega8 vai RS232. The ATMega8 chip has the onchip 10-bit resolution A/D Converter. Temperature sensor are connected to the 6 channels ADC input. You can connect up to 8 sensors with the ATmega8 TQFP package.
Data Acquisition System using ATmega8 - [Link]
Here’s a keyboard-glove prototype in development by Jeff Rowberg. The Keyglove is a glove-based USB input device that provides full keyboard control, designed for wearable and mobile computing and to assist the disabled. [via]
According to Jeff:
The Keyglove is a portable Arduino/AVR-powered glove that uses touch combinations (for keys) and an accelerometer (for the mouse) to generate keyboard and mouse control codes using only one hand. Once learned, the glove can easily be used without looking, making it perfect for embedded/wearable environments. The glove is thin and light, built to allow other activities (such as writing) without being in the way. The current design also incorporates Bluetooth wireless connectivity, a rechargeable lithium polymer battery, simple vibration feedback, audio feedback, and a tri-color status indicator LED.
Keyglove Arduino/AVR-powered keyboard substitute - [Link]