I had the opportunity last week to interview Murray Harms from Queensland Australia, and talk to him about his home made Iron Man Suit. He built it with his son for Halloween and as you can see below, it looks pretty amazing.
Dimming an incandescent bulb is easy. Simply adjust the current down using a potentiometer and you are done. Dimming an LED is another story entirely. When you reduce current through an LED there are unintended consequences like color shifts and dropouts. A better way is to use Pulse Width Modulation (PWM).
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.
EEPROM (Electrically Erasable Programmable Read Only Memory) Is non-volatile memory, meaning it persists after power is removed. The ATmega168 microcontroller has 512 bytes of EEPROM which can be used to store system parameters and small amounts of data. This tutorial shows you how to read and write EEPROM.
Recently a friend asked me, "What do I buy if I'm just starting out with embedded systems and want to learn?". I told him a breadboard solution would be best and started rattling off all the bits that he would need. Then I got thinking, what if we made this a kit? So here it is...
This tutorial will teach you how to use external and pin change interrupts on an AVR microcontroller. I will be using an ATmega168. The general principles apply to other AVR microcontrollers, but the specific vary greatly.
What is an Interrupt?
Imagine your are sitting at your computer, reading this post. The phone rings and you answer it. After you hang up the phone (it was a telemarketer trying to sell you a timeshare), you get back to the awesomeness of the post, picking up where you left off.
Microcontroller interrupts are just like that.
- The microcontroller is executing it's main routine
- An event occurs, which raises an interrupt
- The Interrupt Service Routine (ISR) is run
- On termination of the ISR, the microcontroller returns to it's main routine, at the point where it left off
The ATMEGA168 Development Kit now comes with 10 extra components for the power supply block. Specifically that includes:
- 1 x Resistor - Metal Film 1/4W - 1K
- 1 x LED General Purpose 5mm Yellow
- 1 x DC Jack 2.1 x 5.5mm
- 1 x 1N4004 General purpose 1A Rectifier Diode
- 1 x L7805 +5V Linear Voltage Regulator
- 1 x PPTC Resettable Fuse - 72V, 500ma (RXEF050)
- 1 x Capacitor - Electrolytic 25V 47 uF
- 1 x Capacitor - Electrolytic 25V 100 uF
- 2 x Capacitor - Resin Dipped Ceramic 50V 100nF
When the ATMEGA8 Development Kit becomes available again, it will also have these extra components.
Version 1.5 of the 28 Pin AVR Development Board is now available. As before we have incorporated a number of changes that people had asked for.
The most notable change is a figure-8 shaped hole for mounting the voltage regulator. This configuration allows for both Input/Ground/Output (IGO) and Ground/Output/Input (GOI) style voltage regulators. Other changes to the power supply include the addition of a diode to protect against reverse polarity and a resettable fuse.