Devantech-ultrasound

Version 3 (Anthony Rowe, 10/26/2008 05:46 pm)

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== Devantech SRF02 Ultrasound Interface ==
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This page describes how to connect the Devantech SRF02 Ultrasound sensor to a FireFly sensor node.  This could be used for ranging, or with multiple FireFly nodes, difference in time of flight ranging can be done using the "fake" mode of the SRF02. 
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For more information about controlling the SRF02, please see the following [http://www.robot-electronics.co.uk/htm/srf02tech.htm technical specification].
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[[Image(ultrasound-schmatic.png)]]
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Wire the SRF02 to the FireFly node as shown above.  The battery is optional, but allows the ultrasound transmitter to produce a stronger signal.
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[[Image(ultrasound-1.jpg,400)]]
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This is a photograph of the ultrasound connector wired up according to the schematic.
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[[Image(stacked-header.jpg,400)]]
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By soldering a header on top of the receptical, it is possible to program and receive debugging data from a node even with the ultrasound module attached.  Only do this for boards that will be used for debugging.  Otherwise just solder directly onto the receptical.
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[[Image(jumper.jpg,400)]]
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Adding a jumper to the Ultrasounds UART TX line is required for programming the FireFly node while the ultrasound board is attached.  Since the programming board uses the same UART lines, if the ulrasound TX is left connected during downloads, the ultrasound board may send signals that corrupt the FireFly firmware.
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[[Image(programmer-connected.jpg,400)]]
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The above photo shows the FireFly board with the ultrasound and the programmer connected.