Public Member Functions
def	__init__
def	cancel
def	read
Public Attributes
	pi
Private Member Functions
def	_cbf
Private Attributes
	_cb
	_echo
	_echo_mode
	_high
	_inited
	_ping
	_time
	_trig
	_trig_mode
	_triggered

Detailed Description

This class encapsulates a type of acoustic ranger.  In particular
the type of ranger with separate trigger and echo pins.

A pulse on the trigger initiates the sonar ping and shortly
afterwards a sonar pulse is transmitted and the echo pin
goes high.  The echo pins stays high until a sonar echo is
received (or the response times-out).  The time between
the high and low edges indicates the sonar round trip time.

Definition at line 7 of file sonar_trigger_echo.py.

Constructor & Destructor Documentation

def sonar_trigger_echo.ranger.__init__	(	self,
		pi,
		trigger,
		echo
	)

The class is instantiated with the Pi to use and the
gpios connected to the trigger and echo pins.

Definition at line 19 of file sonar_trigger_echo.py.

Member Function Documentation

def sonar_trigger_echo.ranger._cbf	(	self,
		gpio,
		level,
		tick
	)	`[private]`

Definition at line 45 of file sonar_trigger_echo.py.

def sonar_trigger_echo.ranger.cancel ( self )

Cancels the ranger and returns the gpios to their
original mode.

Definition at line 79 of file sonar_trigger_echo.py.

def sonar_trigger_echo.ranger.read ( self )

Triggers a reading.  The returned reading is the number
of microseconds for the sonar round-trip.

round trip cms = round trip time / 1000000.0 * 34030

Definition at line 60 of file sonar_trigger_echo.py.