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Activities/Turtle Art/Using Turtle Art Sensors (view source)
Revision as of 17:18, 25 November 2010
, 17:18, 25 November 2010→Acceleration on an inclined plane
==Acceleration on an inclined plane==
==Acceleration on an inclined plane==
The XO laptop can be used to do experiments on motion. The XO1.5 is faster and better suited for this. Inexpensive sensor switches can be made of aluminium foil. The switches are 5cm wide to provide an on time which is long enough to measure.
The XO laptop can be used to do experiments on motion. The XO1.5 is faster and better suited for this. Inexpensive sensor switches can be made of aluminium foil. The switches are 5cm wide to provide an on time which is long enough to measure.
[[File:Acceleration setup.jpg]]
[[File:Acceleration setup.jpg]]
Shown below is a triggerable oscilloscope with calibrated timebase. The logging rate can be increased (Turtle Blocks104) by patching one of the Turtle Art files, <i>talogo.py</i> in directory <i>home/olpc/Activities/TurtleArt.activity/TurtleArt</i> changing <i>self.max_samples</i> from 1500 to 150, This reduces the repeat loop from 15mS to 4mS but there is around 50mS jitter. Datalogging can be done without patching the file, using wide switches and shallow ramps keeps the events within the capability of the XO laptop.
Shown below is a triggerable oscilloscope with calibrated timebase. The logging rate can be increased (Turtle Blocks104) by patching one of the Turtle Art files, <i>talogo.py</i> in directory <i>home/olpc/Activities/TurtleArt.activity/TurtleArt</i> changing <i>self.max_samples</i> from 1500 to 150, This reduces the repeat loop from 15mS to 4mS but there is around 50mS jitter. Datalogging can be done without patching the file, using wide switches and shallow ramps keeps the events within the capability of the XO laptop.
[[File:Triggerableoscilloscope.jpg]]
[[File:Triggerableoscilloscope.jpg]]
Switches were placed at 20cm, 60cm, 100cm, 140cm, and 180cm along a ramp of length 180cm and height 23cm.
Switches were placed at 20cm, 60cm, 100cm, 140cm, and 180cm along a ramp of length 180cm and height 23cm.
The oscilloscope data is shown below, each square is approximately 200mS
The oscilloscope data is shown below, each square is approximately 200mS
[[File:Accel oscilloscope.jpg]]
[[File:Accel oscilloscope.jpg]]
The match between theory and experiment is shown below
The match between theory and experiment is shown below
[[File:Acceleration.jpg]]
[[File:Acceleration.jpg]]