Wearable Child Tracker




Introduction: Wearable Child Tracker

About: I am Saiyam, currently studying in 12th standard and soon going to complete high school. I like to make random DIY projects whenever free. I like learning stuff more than studying and cramming up things! You...

Are you worried of your kids getting lost when you are out at a crowded place? That's obvious, isn't it? This project will reduce the risk of children getting lost at unknown and crowded places thus will also eleminate your nightmares. As you may have already guessed from the name, this project is basically a child tracker that can give you the exact GPS location through an SMS to your phone when required.

This project uses the Mediatek Linkit ONE as a base for communication between your phone and the tracker and to get the GPS location. As linkit one has in-built GSM and GPS features, you don't need to connect any external shield or modules which makes it a perfect weekend project to be completed within an hour. You just need a SIM card with some balance or an SMS pack. The best part is that the device will work in any part of this world provided that there is a mobile network available at that place.

The project is enclosed in a digital camera pouch thus can be tied around the waist along with a belt, can be kept in your child's bagpack or pocket. Since the project has GPS, you can not only use it as a child tracker but also as car tracking or bagpack anti-theft device.

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Step 1: How It Works?

The process is very simple. As you may already know, linkit one as in-built GPS and GSM features. So when you send a message to linkit one through your phone, it is received by the SIM card present on linkit one and transferred to the board thereafter.

The board then processes the signal, gets GPS data by directly connecting to a sattelite and then sends this data to the no. which is mentioned in it's code. The data when entered on Google Maps gives you the exact GPS location of the device. As the device will be with your child, it will tell you the location of your child so that you can easily reach that place.

It shall be noted that you will only get the data till the device is on. Unavailability of power supply or the battery running low will not give you the GPS data.

Step 2: Parts and Tools

You will require the parts and tools mentioned below to make this project. Actually, you just need a SIM card and an enclosure if you already have a Linkit one or got it from the recent giveaway here at instructables.

  • 1x Mediatek Linkit ONE
  • 1x 3.7v lithium battery
  • 1x GSM antenna
  • 1x GPS antenna
  • 1x SIM cart (must not be pin locked)
  • 1x Enclosure for your project (I used a camera pouch)

Step 3: Connect the Antennas

The first step is to connect both the antennas in their respective sockets. This should be quite easy. In your linkit one package, look for a yellow colored square shaped antenna (GPS) and a rectangular black one (GSM/GPRS) which is comparatively bigger than the other black one.

Look for the antenna sockets at the back of your boards. Insert and connect your antenna to their respective sockets which are labelled on the board.

Step 4: Connect the Battery and Insert the SIM Card

Next step is to connect the battery and the SIM card. First connect your battery to the white color socket present on the bottom left corner of the board. On setting the big switch to BAT position, you should see the on-board LED light up.

Next, insert the SIM card inside the micro SD/SIM combo socket present below the board. Make sure that your SIM isn't pin locked or it would not work.

Step 5: Stick Everything Together

And that's it! You're all done with the building part of this project. The last step is to tie everything up using some tape. You can also use zip ties.

Try to keep everything in place and make the size as small as possible by arranging the battery and the antennas. Use some tape to keep everything in place. You may need to apply some tape below the board as well to avoid any unnecessary connections with the metal base.

Step 6: Add a Cover or an Enclosure

Here comes the most crucial part of this project. Here, you have to decide as to how to make the assembled project a wearable. You directly keep the board in your child's pocket with all open connections with the risk of breaking them so you have to have a nice enclosure for it.

In my case, I used a camera pouch, which is soft thus would not irritate your child. The pouch can be held together with a belt, can be hung as a locket or can even be kept in your child's bagpack or pocket. However, this was just a basic idea. You can use whatever you want which depends on how well you can imagine.

Step 7: Upload the Code

Upload the code given in the ino file below to your linkit one. If you are uploading the code for the first time to your linkit one, you can follow my Linkit ONE Getting Started Guide to help you set up your board and to get started with it. Before uploading, make sure that switches 1, 2 and 3 should be in UART, USB and SPI positions respectively.

Note: In the line "LSMS.beginSMS("0123456789");", in "void setup()", change "0123456789" to the mobile no. you want the message to be sent.

Step 8: You're Done!

This is it!. All you have to do now is, switch it on, make your child wear it in whatever way you like and that's it! Now your child will be always safe. For getting the GPS location, send an SMS through your phone with any sort of text. You will receive an SMS on to the phone no. that you mentioned in the code. Copy the latitude, longitude and other details on Google Maps and you will get the exact location of your child!

This concludes this instructable as well. Hope you liked it. Don't forget to comment and share your doubts and projects. Please vote if you really like this instructable. Do follow for more great projects!

You can even like my facebook page- Frozen Solenoid for amazing projects and facts related to technology.

Thanks for watching :)

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    18 Discussions


    Question 5 months ago

    Can we use alternatively the arduino board?


    1 year ago


    Thank you for the tutorial, but, I have problem, I am sending SMS message, and not receive anything back, I changed the phone number inside the code to point to my phone, and still nothing happen. Do you know what can cause this issue? or, how I can debug this?

    I had completed the same of this, but it take time to send back SMS does it take time normally for the first time? Should I also put receiver number with International format i.e including zip code (e.g +91.......) or something?

    I had completed the same of this, but it take time to send back SMS does it take time normally for the first time? Should I also put receiver number with International format i.e including zip code (e.g +91.......) or something?

    Thanks bro...

    hi.i like the project.kindly send me the procedure of connection and materials needed.email petergchege.pc@gmail.com.

    I've been trying this and my code keeps returning an error

    Question: I'm 14, unfamiliar with cellular service pricing. How much does the cellular service for the project cost per month?

    6 replies

    you'll have to find out the pricing on the network you'd like to use, then calculate based on how many sms's you'd use a month. or some networks offer SMS bundles.


    This is really for tinkering. You can buy a refurb/pre-owned phone from Freedompop phone for $30. Turn on the GPS and install any GPS tracking software and you are done. The LinkOne module alone costs $50 to $75 (@amazon) bucks.

    Actually the point here was to make one yourself. Making also involves the process of learning against directly buying it which would surely be cheaper but would lack that DIY spirit.

    I absolutely agree. I've made things that would have cost half as much to buy. I didn't mean to imply that is should not be made. That's what I meant about it being for tinkerers.

    Freedom Pop is 500mb a month for free. Unlimited plans are available for $10.99

    Here in the US, a company called Straight Talk has a 30/month unlimited text plan, prices vary wherever you go though.