Stethoscopes are intensively used by physicians. Some of them are modern other are old fashioned. But in many cases technology may help to see what human may skip/not notice. This is why computer aided diagnosis (CAD) is important. Having this in mind Cornel ECE4760 students Michael Wu and Garen Der-Khachadourian constructed a digital stethoscope with many useful features that may be helpful when analyzing cardiac signals.

Digital stethoscope is based on AVR Atmega644 microcontroller which captures sound signal using sensor and digitizes at 8kHz. All captured signals are passed to audio output using PWM for real time auscultation. Additionally signal waveform is recorded in to 1MB external flash memory chip so later waveform could be played back. User interactions are seen in 4×20 LCD and controlled with 16 button keypad. Besides that digital stethoscope sends real time (or recorded) waveform data via USART where Matlab program analyzes it and calculates other derivative information like average hear-beat rate. Having visual information such system may help to detect cardiac murmur that can be unnoticed during standard checkups.

Morse code is basically dashes and dots. Each character is encoded using a mix of them. Human can learn Morse code during some practice. If you don’t want to learn it but still need to decode some messages you can build a simple Morse code interpreter which listens to beep signals and translates messages in to readable text.

This system is based on Atmega8 microcontroller which reads sound signals using microphone and operational amplifier. Then microcontroller reads sound signals using ADC and determines weather particular signal were dash or dot. It can translate 32 characters including aA- zZ and 0-9. Messages are displayed on standard 2×16 LCD.

We all know how sweet sleep can be in the morning. Every last minute counts… If there are kids around then things get different. Simply speaking – they dictate when to wake up and get up. Most frequently this is because kids don’t have a sense of time. So Mike decided to add a little control to kids wake process.

He built an attiny25 based clock called OK Wake. It has a NXP PCF8523 RTC running on it. As kids cant tell time there is no a display just dual color LED. Device simply indicates three parts of day – night, twilight and dawn. Each of them is set to particular time for instance if wake time is 6am, then twilight starts at 5:30am with slow red blink. When time reaches wake time LED turns green wit h”breathing” blink. Kids are great at lights – so when LED turns green its OK to start buzzing arround the house

This Basic interpreter originally was developed by Gordon Doughman and run on Motorola 68hc11 microcontrollers. Karl Lunt admired this work and decided to port it to AVR microcontrollers. He found an ASM source code on internet and converted in to C.

He made several AVR specific improvements to it like saving programs to EEPROM, access to avr ports, timers. Basic outputs information to first USART console. Karl claims that C source code is messy and not optimized so he didn’t publish it. Only compiles for mega128 series MCUs and Atmega90CAN128. That’s reasonable because hex takes just under 29kbytes. Hopefully this project gets decent attention and gets polished, because project looks interesting and useful in many ways.

Haris purchased few IV-11 VFD tubes and decided to build nice looking alarm clock. The tubes itself look impressive when lit. Instead of leaving them as is he also added and RGB LED under each tube. This way Haris could fill them with different color upon menu selection. Currently he chosen Green to indicate time, Blue – date and Red to show alarm time.

The clock runs under Atmga8 microcontroller clocked with 32,768kHz crystal. So no additional RTC IC were used. Tubes require 60V to light up. So there is a simple boost converter on board which converts 12 to 60V. AVR MCU drives it with PWM signal. IF power goes off there is a backup battery that keeps it running without glitch.