1. Sensors for use in this class. Sensors 2 Robotics: Bridgewater state college.

2. Sensors for this class ● Now that we've covered sensors commonly used – Lets look at the sensors available for this class. ● We are using two robot controllers in this class – Handyboard – Lego RCX – Lego simpler but less powerful ● Will use handyboard for first lab, Lego for second. Projects as they come. – Discuss sensors separately Handyboard today.

3. Handyboard

4. Photodiode (light sensor) ● Omni-directional light sensor – Low values for lots of light – High values for little light. – Make directional by wrapping in aluminum foil. – Add two or three and can get direction information about light sources. – Analog ports 2-6

5. IR reflectance sensor ● IR reflectance – “top hat” – Active sensor emits IR radiation and detects it in same direction. – “active range” (min range) of 2 cm; max range depends – Point at nothing? Return high value; point at light colored close obj, return low value. – Generally edge detection – Black/white line following. – Analog ports 2-6

6. IR Range Sensor (E.T head) ● IR Range sensor – Active sensor emits IR radiation and reads the reflectance back. – Effective range is 6-30 inches ● Objects farther away give lower return values. Closer to 6 inches gives higher return values. ● Closer than six inches and the return values decrease again ● Analog ports 16-20

7. Touch/contact Sensors ● Digital Sensors – Help simulate a sense of touch. – 1 when pushed, 0 when not. – Button: push button in. – Lever switch: push on lever ● Very slight force required – Post switch, push in or sideways. – Together primitive sense of touch – actuator/effector limit switch. – digital ports 7-15

8. Break-beam encoder ● Digital encoder sensor – Sends 1 when IR signal between two poles is broken, else 0. – Generally used as digital encoder ● Use gear or wheel with hole in it to encode how many times the hole passes through the beams area. – With software support can develop a speed/distance encoding. – Encoder 0: digital port 7, encoder 1 digital port 8.

9. Handyboard sensors ● Selection of inexpensive analog and digital sensors – No soldering required – Color, light and proximity detection – Touch at a variety of distances from the robot ● Lever very gentle, post fairly gentle. – Encoder capable of recording how many times a particular act was done. – Basic sensing with lots of potential.

10. Lego RCX Brick

11. Lego Light Sensor ● Lego light sensor – Enhanced light sensor ● LED emits small amount of light, then sensor detects light. – Duel use ● Point down: color detection ● Point out: proximity detection. – Return values 0-100 ● Some toolsets 1-100

12. Lego Touch Sensor ● Lego touch bump sensor – Basic on/off digital sensor – Small bump area – Use Lego pieces to provide a larger bumper for sensor.

13. Lego Temperature Sensor ● Temperature sensor – Thermometer – Measures temperature in F or C – Range from -20 to +70 C ● -3 to +157 F – Depending on language used, can get temperature in degrees, tenths, or raw values (0 to 1023).

14. Lego Rotation/Angle Sensor ● Rotation sensor – Gives rotation position and counts rotations. – Has resolution of 22.5 degrees (16 positions) – Can record rotation either forward or backward.