Senior Design Project Fall, 2007Michael Garrity, Peter Nahas,

Cory Haflett

Objective:The Autonomous Mail Deliver System (AMDS) was designed for use in a standard office environment. The AMDS would consist of a reflective track placed on the floor of the office. Perpendicular to the track will be indicators to designate the location of all of the offices. The system can handle 12 deliveries plus one office designated as the main office. The main office will be used at the starting and ending point for the robot. The system will start in a docile state where, at the main office the mail person will load the mail into the appropriate locations and press the button for each office that needs to have mail delivered to it. Once all the mail has been placed into the carrier and the offices have been selected, the mail person will set the robot on the reflective track and presses the Go/Resume button. The robot will then follow the track and stop when it comes to an office that has mail to be delivered. Upon reaching each target office the robot will stop and sound a buzzer to inform the office occupant that there is mail to be pick up. After a time out period the robot will proceed to the next office. This pattern will continue until the robot returns to the main office. If at any point an obstacle gets in the way of the robot, the car will slow down and sound the buzzer as a warning. If the object gets within 10” of the robot, it will come to a complete stop and wait until the obstacle has been moved and the resume button has been pressed.

Initial Sensor LocationsThis is a diagram of the initial sensor layout proposed for our project. The final layout is similar only with two (2) proximity

sensors placed on the front of the robot.

Sample Track PiecesAluminum Ducting Tape was used to

create reflective track pieces. The demo track consists of four 90º turn pieces (each

with a 3’ turning radius) and eight 4’ straight pieces. A Track can be made with

any combination of these pieces

Operating Conditions•Indoor Environment•Flat & Level Surface•Single Tiered Office•Maximum of 12 Offices•3’ Minimum Turning Radius•10” Frontal Obstacle Clearance•9.6V Rechargeable Lithium-ion Battery•6.0V Rechargeable Lithium-ion Battery•Preset Reflective Track

User InterfaceThis is the User Interface for the AMDS. This UI is

used to select which offices will have mailed delivered to them by pressing the button for the

corresponding office. There is one LED/Button pair for each office, as well as an error LED and a

go/Resume Button. The office buttons are also used to acknowledge mail delivery by the recipient.

Button SchematicThe schematic of two buttons. This circuit is

repeated 6 time to handle all the office buttons. Half of this circuit is used for the

go/Resume button

Michael Garrity Peter NahasCory Haflett

Proximity SensorsThis is a picture of the placement of the two proximity sensors on the

front of the robot. These are Sharp GP2D12 Inferred Proximity sensors that will detect objects as close as 4 cm and as far as 80 cm away

(Approximately 2” to 2.5’)

Track SensorsThis is the placement of the five Track sensors. The sensor in the middle of the robot,

as well as the pair to the rear of the front wheels (to the right of the wheels in this picture) will normally be over the track. The very front pair of sensors will be slightly off

the track on either side. As the status of the sensors changes from this ideal states, then the robot will steer it self either left or right in an effort to return all of the sensors to

their ideal states, and thus following the track.

Mail Carrier DesignThis is the design of the mail

carrier. There is a hanging file folder for each of the 12 offices in

the delivery route. The Three surrounding pictures show the mail carrier from a couple of

different angles

Item Retail Price Our Price

Sharp GP2D12 Inferred Proximity Sensors (2) $29.00 $29.00

OPB732 Optical Sensors (8) $32.81 $32.81

Nikko Remote Controlled Car (1) $49.99 $49.99

LED (13) $2.60 $2.60

Push Buttons (13) $2.86 $2.86

HCS12 Development Board $100.00 free

Battery Holder $1.89 $1.89

Mail Carrier $13.99 $13.99

Hanging File Folders $5.00 free

H-Bridge (2) $16.00 $16.00

Piezo Buzzers (2) $3.00 $3.00

Misc. $30.00 $15.00

Total $287.14 $167.14

Project BudgetIncluded in this budget

are all of the major components of this

project. The left column shows the retail price for

the various items that were used in our project, for the quantity that we purchased. The right

column shows the prices that we had to pay. In most cases, we had to

pay retail, however some things were supplied by

the RIT Computer Engineering department, or by us students. Misc.

includes various logic chips, wire solder

connectors and other odds and end parts that

were needed to assembly out robot.

Final DesignThis is the final design of the mail carrier from various angles. The carrier on top was cut to try and reduce the weight of the robot.

Battery PacksThe power supply for the AMDS Robot is two battery packs concealed in the bed of the truck. There is one battery pack that controls the motors and steering of the robot. That is a standard 9.6 Volt Lithium ion rechargeable RC Car battery. The second battery pack is six rechargeable AA batteries. That battery pack controls all of the logic and sensors that control the robot.

User ControlsThe top picture shows the power button used for the system as well as one of the piezo buzzers. The bottom picture show the other side of the robot. That side of the robot has the other piezo buzzer as well as a reset button.