Find My Kid page

Overview

Our project aims to reconnect parents back to their missing children. If a child wanders off in a crowded place, in can be scary for both the parent and the child. Our project will allow parents to reunite with their kids quickly and efficiently. The child will carry an Arduino + bluetooth module device, which will communicate through bluetooth to the parent’s cellphone. When the child and parent are separated by a pre-set distance, both the child’s device and the parent’s phone will respond. The child’s device, which will be carried in a small, portable, and kid-friendly box, will emit a loud noise. Meanwhile, the parent will get a notification on his or her cellphone.

Members

• Alexa Rakusin
• Anaïs Quach
• Manohar Pradhan
• TA: Sam Hoff
• Instructor: Professor Mell

Weekly Log

Link to weekly log

Objectives

Our main goal for our project is to successfully establish communication between two devices: one being carried by the parent and one being carried by the child. Our project is successful if the devices can indicate to the users that they are separated beyond a specified range. At the end of this semester, we will demonstrate our project by separating the home device and the receiver by the necessary range to make the devices respond accordingly.

Challenges

Technical Skills: The biggest challenge we will face is our overall lack of coding knowledge. We will need to learn the code to set up signal communication between the Arduino, bluetooth module, and the phone. Devising the project and list of goals will also pose some difficulties, because we currently lack the experience and background knowledge to grasp what the project will entail.

Size: Another concern is the ergonomic integrity of the device; we want the receiver to be wearable, durable, and safe for a child. Ultimately, the receiver is meant to be worn by a child in a situation in which the child might be active and running around. Realistically, our device should be small and sturdy so that it could not be easily broken by the user. Ideally, we would like our device to be small enough to wear as a bracelet or accessory; however, if the size cannot be reduced we may put the device in a wearable fanny pack-like accessory.

Distance: The HC-06 Bluetooth Module that we are looking to purchase only has a short range of ~10 meters (around 30 feet), which limits the scope of our project.

Cost: Another challenge to consider is the cost of the final product. Realistically, consumers would not be willing to pay a large sum for a product that they would only use for occasional situations or emergent situations. While some parents experience anxiety about losing their children in crowded places, many parents might not feel the need to purchase an emergency-oriented device that would only be useful during unplanned circumstances.

Gantt Chart

Budget

• Arduino (Provided)
• 3D Printing Materials (Provided)
• HC-06 Module Wireless Serial Communication x3: $26.97
• GSM 900: $17.74
• Alarm Buzzer Sensor Module for Arduino: $5.43
• LED(s): $3.00
• 9 volt batteries: $9.49
• 9 volt battery clips with bare leads: $5.39
• Mini toggle switch: $5.29
• Total: $73.31




In-Class Presentation

We presented our project in class on February 24th. Link to Project Presentation

Design & Solutions

Design Overview

Our design consists of two main devices: the phone and the Arduino. We also 3D printed a portable box to carry the Arduino.



Schematic design of Find My Kid system

Arduino Design

The Arduino set-up consists of three main components: the HC-06 bluetooth module, an LED, and a 9-volt battery.

1. Bluetooth Module:
   • Initially, a breadboard was used to make a connection between the HC-06 bluetooth module and the Arduino Uno.
   • The Bluetooth Vcc was connected to the 5V pin of the Arduino in order to provide the supply voltage for the module.
   • The module was grounded by connecting the module GND pin to the Arduino GND pin.
   • The Tx and Rx pins on the bluetooth module were connected to the Rx and Tx pins on the Arduino Uno (pins 0 and 1). A voltage divider circuit was set up between the Rx pin of the module and the Tx pin on the Arduino so that the voltage used for the serial communication is 3.3 V. Thus, we used two resistors in series with R1= 2R2 and the Tx of the Arduino being connected across R2. The Tx pin of the HC-06 was connected to the Rx pin of the Arduino.
   • The red light on the Bluetooth Module indicates connection to the phone. When the Arduino and the phone lose connection due to distance separation, the red light begins to flash quickly. This light indicates to the child that they are out of range from the parent and need to return.
   • The bluetooth is password protected, so other people can’t connect to the device. This should help alleviate some concerns about safety and security.
   • Why we chose this module: We thought about using ultrasonic sensors but had multiple concerns, including: (a) lack of full 360 degree range, (b) physical space/portability, (c) problems with interference (our device is meant to be used in busy places where we’d expect lots of interference). The bluetooth module is good because it has better coverage.
2. LED: The LED, which was our actuator, was connected to Pin 13 and the GND pin of the Arduino. We set it up so that the LED could be controlled through the Find My Kid app on the phone. Typing a "1" command on the app causes the LED to blink. Subsequently typing a "0" command on the app causes the LED to stop blinking. This is a useful feature because it adds an element of user interface and communication between the two devices. This feature can be used by the parent to communicate to the child to return to the parent before going out of range.
3. Battery: We connected a battery clip with leads to the 9-volt alkaline battery. The + end of the battery is connected to Arduino V_in and the - end of the battery is connected to Arduino GND. A toggle switch is attached in series with the battery that allows us to switch the Arduino on and off. We added the toggle for the purpose of battery efficiency; it lets us turn on/off the battery so it’s not always running. We soldered the pins of the toggle switch to the red and black leads of the battery connector.



Diagram of Arduino with attached modules

Phone Design

The HC-06 Bluetooth Module was only compatible with Android devices. After setting up the connections and the circuit and uploading the Arduino sketch, the Android device is paired with the HC-06 via a simple bluetooth connection. The password is set to a specific code using the AT command mode of the HC-06 module so that only the Android device used by the parent can pair with the HC-06 module. Once paired, the app on the phone ‘FindMyKid’ is opened and the HC-06 is connected to the app. Once done, the app is able to send inputs to the HC-06 and the actuators connected on the Arduino respond accordingly.

3D Printed Box Design

The box was modeled using Autodesk Inventor. We chose to print a box to carry the Arduino because if a child is intended to carry the device, it needs to be durable and portable.

We modeled the box to look like a treasure chest. The lid slides horizontally into one side of the box and was modeled by negative extrusions to the inner wall of the box. The box also included a measured space to place an alarm buzzer module with a small hole through the wall of the box so the alarm buzzer can be heard while the box is closed. We also made a separate hole on the opposite end of the box to stick an LED light. For decorative purposes, we embossed the Find My Kid logo on one side, and designed a lock on the other side to make it look more like a treasure chest.

We also decided to solder the wires connecting the Arduino, bluetooth module, LED, and battery in order to make sure it could fit inside the box. To prevent the exposed wires from touching while inside the box, we also added black tubing to coat all of the wire attachments. We specifically cut the black tubing and shrunk it with heat so that it was tight around the wires to take up as minimal room as possible.

Results

Improvements

Future versions of our project should improve on reducing its size and improving the range of communication between the devices. Other potential improvements include measures to promote power efficiency, user interface to describe battery level, ability for the user to set different range settings, and improving overall design and wearability. More specifically:

• Avoid using HC-06 Bluetooth Module
  • If someone wanted to re-make our project from scratch, they would be better off finding a different kind of Arduino-compatible bluetooth module
  • Throughout the semester we went through 4 bluetooth modules (2 arrived deficient, and 2 were blown for unclear reasons)
• Have adjustable ranges
  • Depending on where you’re going you might have different preferences of how far you want your child to be able to wander.
  • You’d have to use a different sensor module (not the HC-06)
• Smaller size
  • We weren’t able to make it work on a mini Arduino, but ideally this device should be as small as possible
• Improve the user interface
  • We’d want the user interface to be more “user friendly” in general
• Speaker
  • Getting a louder speaker alarm for the kid’s device. The ones we had were too quiet and would not have been loud enough at the demo session.

Poster