IR Communications for Atmel Mega644/1284 microcontrollers.
Infrared (IR) can be used for line-of-sight communications over low to moderate range. IR is nice because of the lack of interference (except for sun and compact fluroscent lights) and freedom from FCC regulation. The web site http://tthheessiiss.wordpress.com/2009/08/05/dirt-cheap-wireless/ (Jacob Sikker Remin, 2009) shows how to use a IR remote control receiver and IR LED to send ASCII serial data in a simple, but unreliable, fashion with no error control, packetizing, or other overhead. The transmitter drive uses a clever method to modulate and invert the serial output from the USART transmitter. The circuit is shown below.
Infrared Communications for Atmel Mega644/1284 microcontrollers – [Link]
Annie (Wei) Dai writes:
My name is Annie Dai and I am an ECE student senior from Cornell University. My partner and I created a simple, cheap and smart vowel decoder system for our ECE4760 (microcontroller) final project that is capable of recognizing vowels in human speech.
Current voice decoding systems and voice recognition systems on the market are very expensive. What we have created is an alternative for those who only want real time vowel detection or even a cheap word recognition system using a limited word base.
Specifically, the audio input is sampled through a microphone/amplifier circuit and analyzed in real time using the Mega644 MCU. The user can record and analyze his/her speech using both hardware buttons and custom commands through PuTTY. In addition, the final product also supports a simple voice password system where the user can set a sequence of vowels as password to protect a message via PuTTY. The message can be decoded by repeating the same sequence via the microphone.
A Smart Voice Decoder System for Vowels – [Link]