Automated Mail Delivery System

1. Automated Mail Delivery System Rochester Institute of Technology Senior Design Project Fall, 2007 Michael Garrity, Peter Nahas, Cory Haflett Mail Carrier Design This 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 Initial Sensor Locations This 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. Cory Haflett Peter Nahas Michael Garrity User Controls The 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. User Interface This 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. 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. Battery Packs The 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. Project Budget Included 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. Sample Track Pieces Aluminum 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 Proximity Sensors This 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’) • 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 Final Design This 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. Button Schematic The 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 Track Sensors This 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.