SensorDocumentation

Description

  • The Scout sensor package fuses short to long range sonar with short range IR sensors and LED reflectance sensors to provide feedback about the robots' environment. Commercially available off-the-shelf components were used where possible. The sensors were chosen based on range, accuracy, and repeatability characteristics.
  • A popular rangefinder among low-cost robots is the Sharp Infrared sensor family. These are decent entry-level devices but suffer from interference issues (between sensors) and noise issues (dirty power) all of which make the readings from these sensors very unstable and thus unreliable. Colony has made extensive use of these sensors in the past but has now upgraded to more stable sonar sensors from Maxbotix.
  • Scout still employs a set of IR rangefinders, but these output a digital signal (high/low) instead of an analog voltage. There is some hysteresis around the 10cm trigger threshold but these sensors are otherwise very stable.

SENSORS

Type Item Qty Power I/O Notes Page
Rotation Quadrature Encoders 4 5V 1 INT, 1 GPIO EncoderDocumentation
Acceleration ADXL345 3-Axis Accelerometer 1 3.3V SPI or I2C IMUDocumentation
Rotation/Tilt LISY300AL 1-Axis Gyroscope 1 3.3V 1 ADC IMUDocumentation
Distance Maxbotix LV-EZ4 2 5V 1 PWM, 1 TX RangeFinderDocumentation
Distance/Prox Sharp GP2Y0D810Z 3 5V 1 INT SonarDocumentation
Force Momentary Contact Switch 1 3.3V/5V 1 GPIO Stepper Homing
Force Momentary Contact Switch 1 5V 1 GPIO Front Bumper Switch
Infrared TSOP4838 4 5V 1 GPIO BOM Receiver BOMDocumentation
N/A Electret Microphone 1 3.3V/5V Optional...

References

GP2Y0D810Z0F.pdf - Sharp Digital IR Sensor (365 KB) Dan Shope, 07/30/2009 09:05 am

LV-MaxSonar-EZ1-Datasheet.pdf - Maxbotix Sonar Sensor (405 KB) Dan Shope, 07/30/2009 09:05 am

Building_a_Sonar_System.pdf - Application guide to the Maxbotix Sonar EZ series (10.5 MB) Dan Shope, 07/30/2009 11:52 am