QTI Line sensor
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This page describe how to use Parallax QTI Line Sensor.
We will use this QTI Sensor by the Parallax Inc. as a line following sensor. The sensor is available also in set of four sensors together with mounting material for the complete task, see the QTI Line Follower AppKit for the Boe-Bot.
Please, read the following documentation before You start:
Schematic diagram of the connection type 1 (analogue)
Demonstration program for the analogue readings:
' -----[ Title ]----------------------------------------------------------------
' Line Sensor Test
' {$STAMP BS2}
' {$PBASIC 2.5}
' -----[ I/O Definitions ]------------------------------------------------------
LineSnsrPwr CON 10 ' line sensor power
LineSnsrIn CON 9 ' line sensor input
' -----[ Variables ]------------------------------------------------------------
Sense VAR Word ' sensor raw reading
' -----[ Main Code ]------------------------------------------------------------
Read_Sensor:
HIGH LineSnsrPwr ' activate sensor
HIGH LineSnsrIn ' discharge QTI cap
PAUSE 1 ' wait until stable
RCTIME LineSnsrIn, 1, Sense ' read sensor value
LOW LineSnsrPwr ' deactivate sensor
Display:
DEBUG HOME
DEBUG "Sensor ", CR
DEBUG "-----", CR
DEBUG DEC Sense, CLREOL
PAUSE 100
GOTO Read_Sensor
...and its operation
Schematic diagram of the connection type 2 (digital only)
Demonstration program for the analogue readings:
' Boe-Bot detects tape with QTI module.
'{$STAMP BS2}
'{$PBASIC 2.5}
' -----[ I/O Definitions ]------------------------------------------------------
LineSnsrPwr CON 10 ' line sensor power
LineSnsrIn CON 9 ' line sensor input
' -----[ Variables ]------------------------------------------------------------
Sense VAR Bit ' sensor raw reading
' -----[ Main Code ]------------------------------------------------------------
DO
Read_Sensor:
HIGH LineSnsrPwr ' activate sensor
PAUSE 1 ' wait until stable
Sense = IN9 ' read sensor value
INPUT LineSnsrPwr ' deactivate sensor
Display:
DEBUG HOME
DEBUG "Sensor ", CR
DEBUG "-----", CR
DEBUG BIN1 Sense, CLREOL
PAUSE 100
LOOP
...and its operation
