27404 Parallax Inc, 27404 Datasheet - Page 117

• Manufacturer Part Number: 27404
• Description: COMPETITION RING FOR SUMOBOT
• Manufacturer: Parallax Inc

Specifications of 27404

• Accessory Type: Hobby and Education
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: SumoBot®
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Incorporating the Pulse-Decay Trick into Another Program
Here is how to incorporate the test code from QtiPulseTrickLeft.bs2 into
TestFrontQtiLineSensors.bs2 from Activity #2. The first step is to declare a dummy
name for P6.
Also declare a couple of extra bit variables to store the states of
qtiSigRight
command that passes the threshold amount of time:
Next, move the entire contents of the QTI calibration code block from the initialization
routine into a single subroutine and name it
After the
of the
essentially the same as the code block from the previous Your Turn.
Read_Line_Sensors
DummyPin
qtiStateLeft
qtiStateRight
Calibrate_Qtis:
Calibrate_Qtis
HIGH qtiPwrLeft
HIGH qtiSigLeft
PAUSE 1
RCTIME qtiSigLeft, 1, qtiLeft
LOW qtiPwrLeft
HIGH qtiPwrRight
HIGH qtiSigRight
PAUSE 1
RCTIME qtiSigRight, 1, qtiRight
qtiThreshold = (qtiLeft + qtiRight) / 2
qtiThreshold = qtiThreshold / 4
IF threshold > 220 THEN
ELSE
ENDIF
RETURN
threshold = threshold - 220
threshold = 0
(P8). Remember, they need a snapshot immediately after the
PIN
VAR
VAR
subroutine is called, the program can use a modified version
subroutine that uses the pulse-decay trick. Here it is, and it's
6
Bit
Bit
Calibrate_Qtis
' Turn left QTI on
' Discharge capacitor
' Measure charge time
' Turn left QTI off
' Turn right QTI on
' Discharge capacitor
' Measure charge time
' Calculate average
' Take 1/4 average
' For code overhead
:
qtiSigLeft
PULSOUT
(P9) and
PIN