Final Design Report - Machine Intelligence Lab screen was easy to integrate into the system using the AVR’s ADC capabilities. The screen size was also a deciding factor. III. Speaker,

Final Design Report

EEL4924-Electrical Engineering Design 2

University of Florida

24 April 2012

“Smart Safe”

Team Members: Ryan Griffin & Brie Colon

Project Abstract:

The Smart Safe is a self-monitoring safe capable of remotely alerting its user of

perceived security threats. The safe plugs directly into wall power and its contents can

be opened by entering a password on an LCD touchscreen user interface. The user

must connect the safe to a wireless network by entering the network’s name and

password, which is stored along with other pertinent data on an SD card. The code is

set by the user and can be changed if necessary when the safe door is open. Further

the user will need to enter an email address in order to obtain alerts, which can also be

changed when the safe door is open. If the user inputs a wrong code, a buzzer will

sound and an error LED will light up. After three consecutive incorrect codes are

entered, the safe will take a picture with a built-in camera and email it to the user. When

the code is recognized and accepted, the buzzer will emit a different tone. The safe

door will then be unlocked and a log of previous times when the safe was last opened

will be emailed to the user. An IR sensor will monitor when the door is opened and a

door LED will reflect where the safe door is closed or open. The lock consists of a

solenoid, which can be operated by a microcontroller.

University of Florida EEL 4924—Spring 2012 24-Apr-12 Electrical & Computer Engineering

Page 2/16 Smart Safe

Table of Contents

Project Features………………………………………………………………………………3

Components.………………………………………………………………………………..…4

Technical Objectives………………………………………………………………………....6

Division of Labor………………………………………………………………………..…...15

Projected Timeline………………….………………………………………………….……15

References…………………………………………………………………………………..16

List of Tables and Figures

1. System Block Diagram………………………………………………………………….7

2. Software Process Flow………………………………………………………………….8

3. Schematics / PCBs…………………………………………………………………….10

4. Bill of Materials…………………………………………………………………………14

5. Delegation of Tasks……………………………………………………………………15

6. Gannt Chart…………………………………………………………………………….15



Project Features

The purpose of this project is to create a safe that is both secure and easy to use. It will

require minimal effort on the user’s part to set up. Additionally, the safe will monitor its

state with several sensors. If any of these sensors detects a possible intrusion, the user

will be alerted through various means. Features include:

Robust menu that systematically changes when various criteria are met

Photos from an embedded camera and logs about when the safe was opened

will be emailed to the user

Backup battery power incase of power failure or safe is moved

Power LED (changes color when using battery power instead), error LED, and

door LED give user quick info about the state of the safe

Fail-secure lock will not open when supply is unavailable

Tones from the embedded speaker will aid the user in entering input and alarm

user if pass code is rejected

SD card will keep track of user information and logs



Technology Selection

I. Microcontroller, 2 ATMEGA1284Ps

This AVR was chosen due to its speed, cost and utility. The safe software

depends on interrupts, so a controller with quick response time is needed.

Further, this model has large amounts of SRAM, which is necessary for

managing several memory-intensive parts (i.e. camera, SD card).

II. Touch Screen, Nintendo DS Touchscreen

The touchscreen is a 4 wire resistive touch screen to aid the user in

selecting options and choosing input displayed on the LCD screen. The

touch screen was easy to integrate into the system using the AVR’s ADC

capabilities. The screen size was also a deciding factor.

III. Speaker, 8 Ohm Speaker

The low impedance speaker allows an increase in the output of the

amplifier because of low resistance to current; the speaker can draw more

power from the amplifier. A high quality sound is preferred and that is why

an 8 ohm speaker was chosen instead of a piezo buzzer.

IV. Audio Circuit, 555 timer

A voltage controlled oscillator circuit is used to emit sound to a speaker.

The input voltage comes from the microcontroller and is 5V. The timer

oscillates at a frequency set by a 20k-ohm resistor and a 0.1 micro-farad

capacitor. The voltage applied to the oscillator circuit can change based

on the input voltage. But for the use of the circuit in this system, the input

voltage is set. Also to create more volume a resistor was omitted between

one of the speaker pins and pin 8 of the 555 timer.

V. IR Sensors, IR Emitter and Detector (SEN-00241)

These sensors are used to detect if the door is open or closed. They work

at 940 nm wavelength, which is used for general IR purposes. ADC on the

microcontroller easily interfaces them with the system.

VI. Accelerometer, Triple Axis Accelerometer (MMA7361)

An accelerometer measures they dynamic acceleration of the safe in order

to detect if the safe is being moved. This serves as an anti-theft measure.

It uses 12 bits of accuracy, making it easy to detect subtle changes in

position.



VII. Solenoid Lock, ROB-11015

A solenoid lock is needed to act as a physical deadbolt with electronic

signals. A 6V model was salvaged from another safe. It is powered by

batteries, rather than the AC adapter.

VIII. Status LEDs, Various

Three LEDs were included in the design: error, power, and door. These

Red indicates an error. Orange shows that the door of the safe is opened

(as perceived by the IR sensors). The last LED can be turned to either

green (wall power) or yellow (battery power).

IX. Camera, LinkSprite JPEG Camera

The camera is used in the alarm process to take a picture of the culprit.

The camera is capable of capturing clear color pictures that may help

identify a suspect. The camera uses TTL serial interface (UART). The

camera also includes on-board JPEG compression.

X. SD Card, SanDisk SDSDB-004G-B35

This card was chosen due to its price. It is a high capacity SD card that

can hold 4GB, more than enough for saving logs, pictures, and user

settings. The controller uses SPI to read and write data.

XI. SD Card Adapter Board, SD/MMC Card Adapter

To easily interface the SD card with the PCB board, an SD breakout board

is used. This makes it possible for the user to remove the SD card from

the safe.

XII. Wi-Fi Module, WiFly RN-XV

A Wi-Fi module was incorporated to email logs and pictures to the user in

the event of an emergency. This module includes a wire antenna and only

requires input from a controller. The module uses TTL serial (UART)

communication, making it easy to use.

XIII. Batteries, AA batteries

Four AA batteries supplying 6V are used for backup and to drive the

solenoid and the LCD. For optimal safe working conditions, the batteries

should be changed every 3 weeks.



Technical Objectives

1. The system depends on interrupts from the IR sensors, and the backup batteries via

ADC (see Fig. 1). The controllers are programmed in such a way that they can

resolve interrupt calls quickly or temporarily disable global interrupts to prevent

interrupts in the middle of other subroutines. Interrupts are temporarily halted when

reading or writing to the SD card to prevent data corruption.

2. A particular menu is available to the user based on the state of the safe. When the

safe is powered up, it will detect if any previous settings are saved in memory. If

settings are found, it enters the normal routine (see Fig. 2). If no settings are found,

the user must complete a first time setup of the safe. The user will be able to enter

their password, an email address, and choose a wireless network. After the initial

setup of the safe, the safe will enter the aforementioned process flow. When the

door is closed, the only option open for the user will be to input the code. If correct,

then door of the safe will open. Once open, options to change the code or email

address will be made available.

Safe menus:

o First time setup: Wi-Fi network, password, email, new key code,

confirm key code

o Normal operation: Enter key code

o Door open: Change email, change key code

3. Most components are integrated onto two PCB boards that sit behind the door of the

safe.

4. To avoid interference, the IR sensors are shielded from outside disruptions. At the

same time, the Wi-Fi module maintains a strong connection to the Wi-Fi network. In

order to accomplish these contrary criteria, a wooden safe was used to house all

electronic components.



Block Diagram

Figure 1: System Block Diagram



Software Flowchart

Figure 2: Software Process Flow (Pt. I)



Figure 3: Software Process Flowchart (Pt. II)



Schematics / PCBs

Figure 4: Board 1 Schematic



Figure 5: Board 1 PCB



Figure 6: Board 2 Schematic



Figure 7: Board 2 PCB



Bill of Materials

Table 1: Bill of Materials



Delegation of Tasks

Table 1 shows how tasks were divided on this project.

Ryan Griffin Brie Colon

Preliminary Research 50% 50%

Camera, Memory, Wi-Fi

design

100% 0%

Solenoid, IR sensor, LEDs,

Speaker, Accelerometer

design

0% 100%

LCD, touch screen, power

management design

50% 50%

Board design 50% 50%

Test and Debug 50% 50%

Physical Assembly 50% 50%

Table 2: Division of Labor by approximate percentage

Gantt Chart

Figure 8 displays a timeline for the project.

Figure 8: Project Timeline



References

[1] R. Desai, R. Ramesh. “Designing an Electronic Safe.“ <http://www.eetimes.com/design/embedded/4205822/Designing-an-electronic-safe>.

[2] DharmaniTech. “SD/SDHC Card Interfacing with ATmega8 /32 (FAT32 implementation).“ <http://www.dharmanitech.com/2009/01/sd-card-interfacing-with-atmega8-fat32.html>. [3] K. Maxwell. “Writing drivers for common touch-screen interface hardware.” <http://eetimes.com/design/embedded/4006455/Writing-drivers-for-common-touch-screen- interface-hardware>. [4] “How to use MMC/SDC.” <http://elm-chan.org/docs/mmc/mmc_e.html>. [5] “Interfacing Touch Screen with microcontroller.” <http://mehtadhaval.blogspot.com/2011/04/touch-screen-interfacing-with.html>.

Documents

Final Design Report - Machine Intelligence Lab screen was easy to integrate into the system using the AVR’s ADC capabilities. The screen size was also a deciding factor. III. Speaker,