Figure 14 :: Measuring Speed; Figure 15 :: Compensating For The Height Of The Landing Gear - Lightware SF02 Product Manual

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SF02

Laser rangefinder

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Auxiliary serial port (UART)

The auxiliary serial port, or UART, transmits a serial string of ASCII encoded data from the SF02 to the host controller. The baud rate

of transmission is selected by menu item <5> and can be any of the standard baud rates from 4800 to 115200. By default, there is

one stop bit and no parity or handshaking on this serial port.

The ASCII string representing the distance is in floating point format with two decimal places followed by carriage return and line

feed, as follows:

where carriage return and line feed are given by the hexadecimal ASCII characters:

Data is sent out of the auxiliary serial port whenever a "trigger" notification is received. The ASCII character <D> acts as a trigger

when transmitted by the host controller to the SF02. Additionally, there is an active low, hardware trigger that can be controlled by

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a digital port pin on the host controller.

Measuring speed

The measuring speed can be selected by menu item <6> to be either fast or slow. In fast mode the readings update 12 times per

second. In slow mode, a four point rolling average filter is applied to the distance readings giving a smoother output. The slow mode

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is for making more precision measurements.

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Zero point

The point from which distance measurements are taken can be adjusted using menu item <7>. The range of values that can be

entered are from -1.00 meters to +1.00 meters. This zero point adjustment can be used to compensate for the mounting position of

the SF02 in the final system, where distance readings may best be interpreted from a suitable point on the system rather than from

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the front face of the SF02.

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SF02 Laser Rangefinder - Product Manual - Revision 4

Product manual

"22.48\r\n"

\r = 0x0D

\n = 0x0A

Figure 14 :: Measuring speed

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