AT89S52 Development Board

If you are looking for a simple AT89S52 experimental board, you don't have to go far. You can build one by yourself. This board has two channel 12-bit ADC, a 4-digit seven segment LED , a LCD connector, four tact switches, and the ISP loader to load the firmware.

Source: http://chaokhun.kmitl.ac.th/~kswichit/89S52/89s52board.jpg

DIY: A 3-Digit Digital Voltmeter (Atmega8)

Here's a simple digital voltmeter based on Atmega8 microcontroller. It uses the in-built A/D converter to measure the input analog voltage and displays it on a 3-digit seven segment LED display.

Source: http://tuxgraphics.org/electronics/200706/mini-digital-voltmeter.shtml

DIY: 40MHz Frequency Counter

This project describes how to make a small, cheap and simple frequency meter using Atmega16. It cane measure frequencies up to 40 Mhz with errors below 1%!

Source:http://www.ikalogic.com/freq_meter_2.php

 

The display used is four common anode type 7-segment display. Since an ATMEGA16 microcontroller can source up to 40mA of current per I/O pin, no need of transistors for the 4 enable signals.

ArduIMU Quadcopter: An Automatic Flying Machine

This tiny drone is packed with sonar and IR sensors and is ready for completely automatic flights. For outdoor flights, it can also hold positions based on GPS.