User manual

Copyright © Dr Robot Inc. 2005
101
VII. DUR5200 Ultrasonic Range Sensor Module
VII.1 Introduction
The DUR5200 Ultrasonic Range Sensor Module can detect the range information from 4 cm to 340
cm. It transmits an ultrasonic "ping" when instructed by your program and returns a signal when it
receives an echo. The distance data is precisely presented by the time interval between the instant
when the measurement is enabled and the instant when the echo signal is received. There is an on-
board oscillator that significantly reduces the burden of the controller to transmit signal with the
required frequency. The DUR5200 is very easy to use and can be simply plug-in to the WiRobot
PMS5005 Sensing and Motion Controller board. The PMS5005 (shipped with WiRobot SDK for PC)
will handle the critical timing functions and distance calculation.
VII.1.1 Features
• On-board oscillator
• 4 cm to 340 cm effective range
• 40 KHz working frequency
• Plug-and-play in the WiRobot system
VII.1.2 Applications
• Mobile robot environment map building
• Obstacle detection, collision avoidance
• Robot range finder
• General-purpose distance detection
VII.2 Operations
VII.2.1 Theory of Operation
The DUR5200 works by means of ultrasonic wave (40 KHz) that is beyond the range of human
hearing. Sound wave propagation speed in the air is 343.5 m/s, when the ambient air temperature is
20°C. By detecting the propagation time of the sonic wave between the sensor and the object (if any)
in the path of the wave, the controller is able to calculate the distance.
VII.2.2 Running as Part of WiRobot System
When using the DUR5200 with the WiRobot system, user can simply connect the module to one of
the ultrasonic sensor module connectors on the PMS5005 controller board and the PMS5005 built-
in sensor device driver will take care of the range data acquisition. Users can simply call a function
offered by the WiRobot SDK software on PC (requires Microsoft platform) or send a data request
packet (platform independent) to obtain the data. Note that DUR5200 can measure from 4 to 255 cm
in WiRobot system since PMS5005 only uses one byte to represent the distance.
The sound wave propagation speed in the air depends on the temperature. If you also got the
temperature sensor module in your WiRobot system, you can measure the distance more precisely by
adding up the temperature compensation. The sound wave propagation speed (v) with temperature
compensation can be calculated by the following formula:
v = 331.5 + 0.6 * T [m/sec]
where T is the air temperature (°C).
VII.2.3 Running as a General Purpose Ultrasonic Range Sensor Module