1. Component research Nick Klein

2. Ultrasonic Parallax sensor – A single I/O pin is used to trigger an ultrasonic burst (well above human hearing) and then "listen" for the echo return pulse. The sensor measures the time required for the echo return, and returns this value to the microcontroller as a variable-width pulse via the same I/O pin. – http://www.parallax.com/product/28015

3. ATtiny85 Low-power Atmel 8-bit AVR RISC-based microcontroller 6 general purpose I/O lines, 32 general purpose working registers, One 8-bit timer/counter with compare modes, One 8-bit high speed timer/counter, USI, internal and external Interrupts, 10-bit A/D converter, programmable watchdog timer with internal oscillator, Three software selectable power saving modes, and debugWIRE for on-chip debugging. Operates between 1.8-5.5 volts. http://www.atmel.com/devices/attiny85.aspx

4. Tactile Buttons Single Pull single throw. Readily available at Radio Shack Surface mountable http://www.adafruit.com/products/367#Distri butors

5. LED Bar graph (Red) Forward voltage of 2.2v Not a SMD (Might be a problem) Will need a multiplexer to use Due to GPIO pin limitations. https://www.sparkfun.com/products/9935 Do not recommend this product

6. Battery MCU can operate at 1.8v Ultrasonic sensor needs 5v 10 Segment LED Bar Graph – Blue needs 3.6v 10 Segment LED Bar Graph – Red needs 2.2v We need a battery that can provide at least 5v. Rechargeable is a “Nice to have” Power source can be USB??