1. Project Dachong Bo Liu Department of Physics Dr. A. Antonio Arroyo
Dr. Eric M. Schwartz
Mike Pridgen
Thomas Vermeer
University of Florida
Department of Electrical
and Computer Engineering
EEL 5666
Intelligent Machines Design Laboratory

2. Dachong overview Dachong means big bug. It is a six legged robot.
It has six servos for movement. Each pair of legs has a vertical servo for up-n-down movement and a horizontal servo for forward-n-backward movement.
It uses an Atmega128 chip on PV Board for controlling.
It has a 2x16 LCD display and 4 LEDs for status feedback.
It has 3 IR sensors for obstacle avoidance, 3 CdS cells for light intensity detection and a 3-axis accelerometer for acceleration detection.

3. Mechanical structures of Dachong
Main shaft
Battery pack
Electronics mount
IR mount
Rear legs assembly
Middle legs assembly
Front legs assembly

4. Mechanical structures of Dachong
Vertical Servo
Vertical gear
Leg mount
Horizontal gear
Horizontal servo
Vertical servo mount
Vertical shaft
Main shaft
Pivot support
Horizontal servo mount

5. Sensors on Dachong
Bump sensor
Accelerometer IR
CdS cells

6. Special sensor: accelerometer
Model MMA7260Q from Freescale Semiconductor
. Selectable Sensitivity (1.5g/2g/4g/6g)
. Low Current Consumption: 500 μA
. Sleep Mode: 3 μA
. Low Voltage Operation: 2.2 V V
. High Sensitivity (800 g)
Operation principle
. Two surface micromachined capacitive sensing
cells (g-cell).
. g-cell: a set of beams attached to a movable
central mass that move between fixed beams.
. Acceleration cause central mass and beams to
move, changing the capacitance of 2 back-2-back capacitors.
. Measurement of the capacitance difference indicates the acceleration.

7. Behaviors of Dachong System start Record dark CdS value
Click bump switch
Record dark CdS value
Click bump switch
Record bright CdS value
Click bump switch
Obstacle avoidance walk
IR sense obstacles
Click bump switch
CdS sense bright light
Obstacle avoidance turn
Level
Move to brightest spot
Accelerometer

8. Thank you!