CSC 161 Grinnell College Spring, 2012
 
Imperative Problem Solving and Data Structures
 
 

Sensors for the Scribbler 2 Robot

A Scribbler 2 robot has numerous sensors for detecting the world, and the MyroC library provides function calls to obtain data from the sensors.

The following figures indicate which functions reference which sensors.

Scribbler forward

Scribbler 2 with
                                                  scribbler-forward
Sensor Set Vector Function Text Functions Number Functions Values Returned Comments
Light Sensors
(really darkness sensors)
int vals[3]
rGetLightAll(vals);
rGetLightTxt("left");
rGetLightTxt("middle");
rGetLightTxt("right");
rGetLightNum(0);
rGetLightNum(1);
rGetLightNum(2);
bright light returns values near 0;
dark areas return large integers (about 65,000)
bright, direct light needed for small-value results
 
IR Scribbler Sensors int vals[2]
rGetIRAll(vals);
rGetIRTxt("left");
rGetIRTxt("right");
rGetIRNum(0);
rGetIRNum(1);
output 0 indicates no obstacle;
output 1 indicates obstacle
light must reflect from emitter to receiver, so obstacle must be a 4-6 inches away

Fluke forward

Scribbler 2 with fluke-forward
Sensor Set Vector Function Text Functions Number Functions Values Returned Comments
Obstacle Sensors int vals[3]
rGetObstacleAll(vals);
rGetObstacleTxt("left");
rGetObstacleTxt("middle");
rGetObstacleTxt("right");
rGetObstacleNum(0);
rGetObstacleNum(1);
rGetObstacleNum(2);
0 indicates no obstacle (no light reflected from emitters)
large integers (about 6,000) indicates obstacle
value returned depends upon battery strength and output; level of emitters (set by rSetIRPower(level), where level in range 0, 255)