Category Archives: Safeband

by Eric Freitas and Victor Tavares
Project Description at:

Safeband Final Post


Describe what your project does and how it works

The Safeband is a wristband designed for emergencies. Once connected through Bluetooth the Safeband app can run on the background of your smartphone. In case of an emergency you just need to push the discreet button of the wristband and an email with your name and location are going to be sent to your previously selected contacts.

What are your overall feelings on your project? Are you pleased, disappointed, etc.?

We are very pleased with the project. Although the life sensor feature could not be implemented in time due to hardware, time and knowledge limitations we managed to learn a lot when working with the Arduino and its Bluetooth. We enjoyed the project to a point that we are going to try to evolve the idea a little more when we are back to Brazil.

How well did your project meet your original project description and goals?

The very first goal of the project was accomplished. We left all classes with a feeling that we had learnt what we needed for that day to continue to press forward with the project. We were worried at the beginning that the life sensor was changed for an accelerometer and later canceled, but these features were addons in the first place so our project did meet the original project description.
What were the largest hurdles you encountered? How did you overcome these challenges?
The lack of knowledge for sewing and electronics impacted our progress in the beginning, but we teamed up with Vinicius Furlan and Jhonatt Lima and we managed to learn the basics in electronics. The Firebase also helped a lot in the app development, but we lost some time trying to understand the inner workings of installing and running plugins and they were necessary for the Bluetooth connection. Luckily Victor found some results after some hours of struggle.

If you had more time, what would you do next?

Certainly we would improve the Bluetooth connection and add text message support. Seeing how the Internet is as not reliable as SMS we would be better off with a product that supports this kind of communication. Also, in Brazil is much more common to not have an Internet data plan and sending emails would be much more restricted than in the US. The life sensors that we could not add with the time we had available would be a nice feature to have as well.

SafeBand – 07/12

  • What did you do this week?

We worked on the Bluetooth connection and on the send e-mail functionality from the app.

The Bluetooth is working fine and the app is now able to send e-mails.

  • Describe the problems you encountered

We had problems to send e-mail due the filter encountered in the major e-mail web services companies such as Google and Microsoft Office. To solve this problem we had to use a external framework called MailGun (

  • Describe the successes you had

Now we’re able to send email through the app and the Bluetooth connection looks like to be working fine.

  • Are you on schedule?

We’re a little late, but we will be able to finish everything.

  • What do you plan to do next week?

We will make the necessary connections between smartphone and the device and sew everything.

SAFEBAND – 11/30

  • What did you do this week?

We worked on the accelerometer, but we failed to understand what was the problem, the Bluetooth module and the smartphone app.

  • Describe the problems you encountered

I think the wiring in the accelerometer must have fried the circuit. The readings we are getting are very inconsistent and they do not make sense. I am afraid we are going to be behind schedule because of it, but hopefully we can work on other parts of the prototype while we wait for the new accelerometer.

  • Describe the successes you had

We found out how to connect the bluetooth module to the board and I began the testing with it. Victor worked heavily on the app and the functions Login, List Contact and Add Contact are working properly and he made sure they are connected with firebase as a backend framework

  • Are you on schedule?

It depends if the accelerometer is really fried or not. If it is we are will be delayed, but we can work on the app while we wait for the new piece and if it is not then we are on schedule.

  • What do you plan to do next week?

Probably order again a new accelerometer, sew the the bluetooth module after finishing the tests and send emails via bluetooh with the smartphone.


Contact List

Side Menu

New Contact

SAFEBAND – 11/23

  • What did you do this week?

We developed the hardware using the accelerometer and the software and its connection to the server.

  • Describe the problems you encountered

At first we were unsuccessful in wiring the accelerometer to the board.

  • Describe the successes you had

On Thursday class we learned how to wire the 3.3v accelerometer to the 5v Arduino by using a LED as a resistor.


The app is starting to connect to the server and is synchronizing contacts.

  • Are you on schedule?

We are a little bit delayed on the hardware end. But we are comprehending how things are supposed to work now and everything should be on schedule this next week.

  • What do you plan to do next week?

Wiring the Bluetooth and make the first messages appear on the smartphone app.

SafeBand – 11/09

Week’s Accomplishments:


This week we started to develop our mobile application for our project. We’re using a backend framework  and cloud storage called Firebase ( This will save us a lot of time because we will not need to develop our own backend REST API.


We are also using a project management system called Trello( Using this tool we can keep track of our work and schedule our next steps.


We finally bought all the hardware that we will need for our prototype, it included:

  • Arduino pro Mini 328 – $10,00
  • Accelerometer ADXL 335 – $15,00
  • Bluetooth device – $25,00



We were planning to use a pulse sensor, but we figure out that most of them just works when you put the device on the tip of the finger or the device required a really precise position at the wrist to work.

Due to this problem we decided to change the pulse sensor for an accelerometer to detect falls. We are planning to detect when someone falls and stay on the floor for more than 10 seconds, if it happens we will send an alert e-mail at the same way as if someone had pressed the button.


Next week:

We are planning to finish the basic features from the mobile application and if the hardware arrives we will test if everything is working fine making sure that we can do everything that we want.

11/2 Safeband

Project Title – Safeband

Project Team Members – Eric Freitas and Victor Tavares

Description of what you are going to do – We want to build a wristband that allows the user to send messages in times of emergency. The wristband will connect to the user’s smartphone and by presenting a number of conditions and effects it will be able to send messages for help when something happens.

Concept Art –

mockup  contact screen

Description of what inspired this project – There are already some improvements on security and awareness when you are on the streets, but when something like a car accident happens you need to receive help immediately and by sending messages to your family and to emergency numbers you will be able to receive the needed help sooner. There is a project in which they have put sensors on a hair clip and when sudden movements happened it would trigger the alarm and warn family and authorities, this project seems similar, but we think that a wristband is usable by both men and women and also that being able to customize the messages and who receives it is a major feature.

Description of Materials you plan to use along with the costs for these materials –

Small Arduino board – US$10,00
Bluetooth shield – US$25,00
Pulse sensor – US$30,00
RGB LED – US$8,00
Button – US$1,50
Battery – US$2,00

Steps/Timeline –
1st Week – Buy materials and see Bluetooth Communications
2nd Week – Work on send email
3rd Week – Design the app
4th Week – Work on vital sensors
5th Week – Testing and Debugging
6th Week – Final fixes

Backup Plans / Fallback plans – To use the last two weeks to test it thoroughly and, if needed, to simplify the project.