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Two Years of VEX. Mike Martin King HS, Riverside, CA February 22, 2013. Purpose. To share two years of ideas and findings with POE, CIM, and GTT teachers. To stimulate questions and discussion about VEX in the classroom. Battery Storage and Charging. The New Test Bed. The VEX Gear Box.
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Two Years of VEX Mike Martin King HS, Riverside, CA February 22, 2013
Purpose • To share two years of ideas and findings with POE, CIM, and GTT teachers. • To stimulate questions and discussion about VEX in the classroom.
Cortex Capabilities • The Cortex is extremely versatile. Any sensor that falls within specifications can be connected. • Analog characteristics: • 3 dB bandwidth of 16 kHz. • Analog input range: 0.0 v to 5.0 v. • Tolerant of -0.5v to +5.5v. • Only configurable as analog inputs. • Digital characteristics: • 3 dB bandwidth of 150 kHz. • Needs 0.0 to 0.6 volts for a low and 2.5 to 5.0 volts for a high. • Tolerant of -0.5v to +5.5v. • Can drive a 1 mA load to 1.6v or lower for a low and 1.4 volts or higher for a high.
Basic Analog Sensors • Connect basic analog sensors to the Signal and +5V lines on the Cortex • Configure them as a light sensor or potentiometer in ROBOTC
Basic Analog Sensors • The Potentiometer, Light Sensor, and Line Follower sensor types all perform simple A-to-D conversions on sensors, so any of them can be used with simple 3rd party analog sensors • Any sensors you configure will appear in the Sensor debug window, and can be accessed using the SensorValue[] command
Basic Analog Sensors • The Touch and Digital In are basic sensor types and can be used with the basic digital sensors • Any sensors you configure will appear in the Sensor debug window, and can be accessed using the SensorValue[] command • If wired incorrectly, the sensor may have inverted logic values (pressed = 0)
Basic Digital Sensors • Connect basic digital sensors to the Signal, +5V, and ground lines on the Cortex • Configure them as a touch sensor or digital input in ROBOTC
Basic Digital Sensors • Connect basic digital sensors to the Signal, +5V, and ground lines on the Cortex • Configure them as a touch sensor or digital input in ROBOTC Red - +5V Ground Signal
Advanced Sensors • Advanced sensors (ultrasonic, gyroscopes, ect) require that you perform calculations on the raw sensor data to get useful information (centimeters, degrees-per-second, ect) • These calculations are often referred to as “Sensor Drivers” • Value-returning functions can be very useful in these instances
Other Findings and Ideas • Don’t do POE Activities 3.1.1 through 3.1.6 (or the CIM equivalent) • Too much Copy and Paste • Doesn’t give programming practice • Activities written for older version of RobotC • Instead, give the students ‘scenarios’ that they can use as programming practice • Prepare your own • Use the one I developed (on flash drive or email me with a request) • There is a document on the flash drive which details the EXACT order to set up a Cortex to communicate with a computer.