Project: Physiotimer

Description:
	This project was built to automate the timing of exercises that I help
	my wife with to keep her back in shape.

	The timer counts about 30 seconds for each leg and must be repeated 5 
	times.

	The unit contains a mercury level-switch and is started by turning the 
	unit upside down.

	The beeper sounds once per second to indicate that the unit is running.
	The beeper sounds for a whole second when it is time to change legs.
	
	3 seconds are allowed to change legs therefore the timer counts 33 
	seconds per leg.
	
Design:
	The schematic is drawn using xcircuit
	http://bach.ece.jhu.edu/~tim/programs/xcircuit/

	The jpg image was created with a screen capture and may not be as 
	up-to-date as the schematic.ps file.
	
	The program was assembled using gpasm
		gpasm ptimer.asm
		
	The PIC16F84 was programmed using picp
		picp /dev/ttyS1 16F84 -wp ptimer.hex
		
	Three AAA batteries are used for the power supply.
	
	A mercury level-switch (similar to those found in many thermostats) is
	used for the power switch.
	
	A 0.1uF capacitor (not shown on the schematic) is used across the IC
	to smooth out fluctuations caused from weak batteries while the beeper
	is sounding.
	
	The unit does go to sleep when the timer is finfished but it still 
	consumes power, it is best to shut the unit off when done by tipping
	upright.
