2. Dissecting a Sandwich Mark Gordon Engineering 315 December 9, 2002

3. What is Sandwich? Line Following Robot From Robot Building for Beginners –David Cook Follows Either a Light Line on a Dark Surface or Dark One on a Light Surface

4. Sensors Cadmium Sulfide Photo-Resistors –Variable Resistances Cause Variations in the Voltage Drop White LED –Reduce Shadow Effects –Allow for ‘Night Runs’

5. Feedback Voltage Comparator Chip –Senses which Set is Closer to the Line –Produces a Ground or Disconnect A Pullup Resistor Converts it to Ground or High –High Causes the (Opposite) Motor to Run

6. Building Circuit –Breadboard LED Circuit Headlight Circuit Other –Sensors, Motors, Side LEDs, and Comparator Chip –PCB

7. Building Body –Ziplock Sandwich Container –Lego Wheels –Gearhead Motors –Coupler

8. Debugging Side LEDs –Show Which Motor Sandwich Thinks Should be Running Check Overall Resistance –Check Individual Resistances –Find Bad PhotoResistor 

9. Parameters LED Brightness –Brighter LEDs Sharper Reactions –Will Turn Sooner Picks Up Lower Variations in Color –Dimmer LEDs Uses Less Power Reactions are not as Abrupt –More Likely Both Motors will be Running

10. Demonstration

11. Credits Electronics Aid –Chuck Holwerda Machine Shop Aid –Dave Ryskamp Time Provider –Professor Ribeiro Book Writer –David Cook Putter-Upper-Wither –Rachel McNamara

12. Questions ?

13. Motor Control Function