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LW20 / SF20 LiDAR sensor
Product manual
When viewed from above, the lower PWM setting turns the servo shaft to the extreme left position and the higher PWM setting turns
it to the extreme right. The midpoint position corresponds to the PWM value that is halfway between the two end settings.
Figure 20 :: Setting the servo's limits of motion using the PWM values
For each degree of motion by the servo, the PWM pulse width needs to change by a specific number of us. This "PWM scale" can
usually be found on the data sheet of the servo. Alternatively, you can measure how many degrees the servo moves for a 1000 us
change in PWM pulse width and calculate the PWM scale from this result. The default scale value is 10.00 us per degree as shown in
the picture below:
Figure 21 :: Setting the servo's PWM scale
Once the settings have been entered, the servo can be manually positioned using the slider near the bottom of the graphic page.
This slider works in 5 degree increments. The central or middle position can be checked by pressing the "Go to midpoint" button.
The midpoint should be lined up with the forward direction of whatever the servo is mounted on. In the graphic, the physical range
of angular motion of the servo is shown as a grey segment.
Note that settings will only be saved to the LW20 once the "Save" button in the bottom left corner of the screen has been pushed.
Once the electrical characteristics of the servo have been entered using the method above, the servo can be used to aim the LW20 in
a specific direction or autonomously scan the LW20 to produce LiDAR maps and provide collision warning alarms.
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LW20 / SF20 LiDAR - Product manual - Revision 7
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© LightWare Optoelectronics (Pty) Ltd, 2018
www.lightware.co.za
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