This document describes the design and implementation of an autonomous robot named Optimus Subprime. Key features include ultrasonic sensors and infrared technology for collision avoidance navigation and data sampling. The robot uses an H-bridge circuit to control bi-directional DC motors for driving and steering. Sensors measure temperature, humidity, and light intensity for data collection, though radio frequency technology was not used for transmission. The design was simulated, prototyped, and tested, with results showing autonomous driving and decision-making but some difficulties avoiding collisions due to sensor limitations.

1. Dominick Squillace & Kevin Grignoli
ELT 243
5/13/2013
Prof. Biscardi
AUTONOMOUS ROBOT
AUTO_BOT

2. CODE NAME: OPTIMUS SUBPRIME

3. DESIGN
• SCCC Interscholastic Rover
• Autonomous RC vehicle with embedded systems for collision
avoidance navigation and data sampling with the anticipation of
data transmission.
• To be achieved by the use of ultrasonic sonar ping sensors
and infrared technology.
• Engineer circuits for driving bi-directional DC motors.
• Incorporate sensors and RF technology for data collection
and transmission.

4. ULTRASONIC SONAR PING SENSOR
Theory: The ping sensor measures distance using sonar.
An ultrasonic pulse is emitted from the unit and distance to
target is determined by measuring the time required for the
echo to return.
Real Life: The accuracy of the ping sensor is
severely limited by real world scenarios. Small
objects and shallow angles will not produce an
echo as the sound waves will not bounce back.

5. INFRARED TECHNOLOGY
Frequency formula Duty cycle formula
Concept: Generate a 38kHz pulse train through an
infrared LED and is reflected off of objects and detected
by a 38kHz infrared receiver.
(Like shooting a remote control at a wall)

6. H-BRIDGE
Theory: The implementation of four switches to control a DC motor in two directions.
When two opposite switches are closed, the motor will operate in one direction and
in another for the other two switches.

7. SENSORS
DHT11-3 pin Digital
Temperature and Humidity
Sensor
• Measures temperature
from 0~60’C
• Accuracy of +/- 2’C
• Measures humidity from
20-90% RH with +/- 5%
accuracy
BH1750FVI Light Intensity
Sensor
• Measures in lx (Lux meter)
• Wide range and high
resolution
• “Small” measurement
variation of ONLY +/- 20%
• Little light source
dependency

8. RF TECHNOLOGY ))))))))))))))
NRF2041B 2.4GHz
• Up to 1Mbps working speed
• 125 Channels
• High anti-jamming GFSK
• Intended to send collected data to a remote
location. Was not used. 

9. SIMULATION – MULTISIM!
Original design created in Multisim. Utilized an excessive amount of transistors and
arduino pins. Very inefficient use of power.

10. SIMULATION – MULTISIM!
Refined H-Bridge design- More efficient use of power and space.
SteeringDriving

11. SIMULATION – MULTISIM!
• Built in MultiSim
accordingly.
• Circuitry verified
with oscilloscope.
• 26 micro second
period equates to
38kHz frequency.

12. SIMULATION – MULTISIM!

13. IMPLEMENTATION
If you ain’t first, you’re last ;)

14. IMPLEMENTATION
Original H-Bridge Design
First bread-boarded, tested, and
working version.
Utilized too much real estate, and
high power inefficiency
Refined H-Bridge Design
Embedded final version that was put into the car.
Smaller, more compact, and power efficient.

15. ROAD TO THE TOP!

16. IMPLEMENTATION
Improved H-Bridge Circuit Design (steering
pictured)
Refined H-bridge circuit design, more compact and
power efficient. New design was powerful enough
for the steering h-bridge to drive the main motor.

17. TURN ‘N’ BURN

18. IR “TECH”
Pre-manufactured
IR sensor
• Limited Range
Reversed engineered
homemade version
• More power
• Greater range

19. IR “TECH”
• Incorporated re-engineered design
with more IR LEDs and IR
receivers.
• Consumes more power but is
easily handled by a single 555
timer.
• Implemented as a reverse
detection sensor.

20. PROTOTYPE
One ping sensor proved to be
ineffective in creating a comprehensive
field of view.
In order to sense adjacent objects, two
additional ping sensors were
incorporated at 45 degree angles to the
original.
This addition allowed for a greater field
of vision for the vehicle , and a better
chance of object detection.
“THE BUBBLE”

21. IF(CODE RED : CODE);
• By far most difficult part of the
project.
• Required endless amount of
parameters for directive
processing.
• Subtle changes in code made
huge impacts in testing
environment (hallway/corners)
• Simplicity was key.
• Less variables allowed for
simpler processing and decision
making.
 Only represents 1/3 of just
the driving parameters

22. PROTOTYPE
• Hit the brakes!!!! ……………….JK, We don’t have any
• Through testing, it was evident that simply cutting power to the motor was not
enough to stop Optimus Subprime in his tracks.
• Its massive weight combined with the low coefficient of friction of rubber on
freshly cleaned school hallway floors proved to be a hurdle that was not easily
jumped.
Using the relay to short out
the drive motor leads, created
an effective braking system
that could easily stop within a
reasonable distance as to not
collide with objects
…….…most of the time.
Effective braking requires a
completely shut down H-bridge to
prevent the battery from shorting
out.

23. PROTOTYPE

24. PROTOTYPE

25. PROTOTYPE
Layered... like onions

26. PROTOTYPE

27. RESULTS
 Autonomous robot car
• Drives by itself
• Makes decisions
• Maneuvers
 Data collection
• Samples light and temperature
• X Does not transmit data
 X Avoids collisions but has difficulties in some scenarios.
• Limitations created by sensors available and time/$$$ budget
• More and/or better sensors needed.

28. RESULTS
…….Oh Snap

29. IN CONCLUSION ………..

30. REFERENCES
• www.Parralax.com
• www.buildcircuit.com
• www.kerrywong.com