Parallax 555-28027 User manual

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Copyright © Parallax Inc. Page 1 of 6
Parallax PIR Sensor KickStart (#555-28027)
What It Can Do
•Detects motion of humans or animals from as far away as 30 feet
•Silent operation for alarms, motion activated nightlights, holiday props
•Automatically resets after period of inactivity
Passive infrared (PIR) sensors detect motion by comparing the amount of infrared radiation that
reaches a pair of detectors. When the two detectors “see” different values, the sensor indicates it
as movement of an object, such as a person or an animal. PIR sensors are often used in driveway
security systems, which turn on a light (but only at night) when someone approaches the house.
The Parallax PIR Motion Sensor has a simple on/off output: when on, the sensor is detecting
movement. When movement stops the output turns off (after a short delay). The output of the
sensor can be directly connected to a microcontroller, and operates much like a switch. You can
use the on/off condition to directly read the current status of the PIR sensor.
A selectable jumper on the sensor lets you set working distance:
•L (for Long) position, the effective sensor distance is up to 30 feet. This increases the sensitivity
of the sensor, which may also cause more false triggers.
•S (for Short) position, the sensor distance is up to 15 feet.

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For proper operation the sensor should be allowed to warm up for 20 to 60 seconds after first
applying power. This lets the infrared detectors stabilize. The sensor output is not reliable until
the sensor has warmed up.
This KickStart is for Rev B of the PIR Motion Sensor. Earlier versions of the sensor operate in a
slightly different manner. Check the Parallax website for information on using earlier versions of
the sensor.
Parts List
•PIR Motion Sensor
•BASIC Stamp HomeWork Board, Propeller Board of Education, Propeller QuickStart, or Arduino
Uno microcontroller
•22 gauge solid conductor hookup wire

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Basic Wiring
•Power requirements: 3 to 6 VDC: 12 mA @ 3 V, 23 mA @ 5 V
•Single bit output: high (triggered) or low (no trigger)
•Dimensions: 1.41 x 1.0 x 0.8 in (35.8 x 25.4 x 20.3 mm)
Program KickStarts
Each of the example programs display the current state of the PIR module in a terminal/debug
window. A settling or “warm up” period is included at the start of each program. Once the sensor
is ready, trigger it by waving your hand in front of the plastic dome.
Note: A red LED inside the dome will glow when the module is triggered. Simultaneously, the
status of the module should change in the terminal/debug window. The sensor will remain
triggered as long as there is continuous movement in front of it. Once motion stops, the sensor
resets itself after approximately 10 seconds.
BASIC Stamp HomeWork Board

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' {$STAMP BS2}
' {$PBASIC 2.5}
DEBUG "Warming up..."
PAUSE 20000 ' PIR warm-up time
DEBUG CLS
DO
DEBUG HOME, "IN0 = ", BIN1 IN0 ' Display state of PIR sensor
PAUSE 100 ' Small Delay
LOOP ' Repeat Forever
Note: When this program is run, the BASIC Stamp Debug Terminal will automatically open.
Propeller BOE and Propeller QuickStart
Propeller BOE Wiring Diagram
Propeller QuickStart Wiring Diagram
OBJ
pst : "Parallax Serial Terminal" ' Use Serial Terminal object
CON
_clkmode = xtal1 + pll16x ' Set clock mode
_xinfreq = 5_000_000
VAR
byte state ' Variable for storing PIR output
PUB PIR
dira[0]~ ' Set pin 0 to input

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pst.start(115200) ' Start Terminal at 115200 baud
pst.str (string("Warming up..."))
waitcnt(clkfreq * 20 + cnt) ' PIR "warm-up" time
pst.clear ' Clear the screen
repeat
state := ina[0] ' Save state of PIR Sensor
pst.home ' Move cursor to upper left
pst.str(string("IN0 = "))
pst.bin(state, 1) ' Display results
waitcnt(clkfreq/200 + cnt) ' Small delay
Note: This program uses the Parallax Serial Terminal object library, which is included with the
Propeller Tool software download.
Note: To view the results of the demonstration, after uploading is complete run the Parallax
Serial Terminal from the Run menu, or press F12. Momentarily depress the Reset button on the
Propeller QuickStart board to restart the program.
Arduino Uno
void setup() {
Serial.begin(9600);
Serial.println("Warming up...");
delay(20000);
}
void loop() {
Serial.print("IN2 = ");
Serial.println(digitalRead(2), DEC);
delay(200);
}
Note: To view the results of the demonstration, after uploading is complete click the Serial
Monitor icon in the Arduino IDE. This displays the Serial Monitor window. Momentarily
depress the Reset button on the Arduino board to restart the sketch.

Copyright © Parallax Inc. Page 6 of 6
For More Information
•View the PIR Motion Sensor (#555-28027) product page for full documentation.
•The PIR Mini Sensor (#28033) offers similar functionality as the PIR Sensor (Rev B), built in a
smaller module.
•The Wide Angle PIR Sensor (#28032) provides a larger 180˚ field of view
•The X-Band Motion Detector (#32213) uses microwave radio signals to detect motion. This
sensor even detects motion through windows and most walls, and is less susceptible to false
triggers than passive infrared modules.