FitBit – Activity Tracker

The personal activity tracker works in conjunction with a mobile android app. The user is able to track the amount of calories and steps taken per day in order to maintain a healthier lifestyle!


Lauren Z

Area of Interest

Software Engineering


Leland High School


Incoming Senior

Final Milestone

I reached my final milestone by successfully implementing an on off switch to my FitBit and compacting the modules. I first transferred my wiring from the breadboard to a PCB. This way I was able to cut down on a lot of the bulky wiring and make my smart watch a lot more portable. Then I soldered on all the VCC and Ground pins, purposefully making sure to short circuit the pins to establish a strong connection. I aligned my on off button to cut the connection when the switch was off and make a connection when the switch was on. This process took the longest time because the pins are all very close together, so soldering was difficult. Another roadblock I encountered was that the female to male jumper wires were all too long and made the watch look bulky. So, I decided to make my own jumper wires by taking short female to female ends and attaching a small metal tip. This worked out pretty great as my device is now compact. I then modified my code, as shown here,  to fit the new on off switch. Finally I packaged all the modules into this small cardboard cutout and super glued it onto a wrist band. In the future I will modify the project by making it even more compact and adding LED lights. 

Second Milestone


 I reached my second milestone by connecting the bluetooth to my mobile app and successfully sending data from the accelerometer to the user.  I actually started out with the arduino pro mini, but throughout the process my bluetooth kept connecting and disconnecting to the android. I tested it multiple times, trying to figure out where the problem was. Ultimately I decided it was either a wiring problem, or that the arduino mini just did not supply enough power to the bluetooth. So I switched to the arduino nano and then the full sized arduino. The bluetooth was finally working with the full sized arduino. Some difficulties I encountered was rewiring everything because the arduino mini and full sized arduino have different pin orientations. My next step is to get rid of the breadboard by directly soldering the wires together to make the device more portable. I’ll also develop a way to package the modules into a watch format. 

First Milestone

I reached my first milestone by successfully modifying the arduino sensors to interact properly together and also upload my code from the IDE onto the arduino. I started off by assembling all the physical interior modules of the FitBit by correctly soldering on pins and wiring all the pieces together. The arduino is connected to an Accelerometer, HC 06 bluetooth, and a USB to UART converter. I decided to first prototype my project using the breadboard just to make sure all the modules interact with each other correctly. Later I will make the device portable by directly splitting the wires and soldering them together.  The next step i took was developing the code on the Arduino IDE. I was able to modify it to fit the purpose of tracking the user steps and calories. I then struggled to upload the code onto the Arduino pro mini. This was a major roadblock because I did not realize that if the RX and TX pins were plugged in, then the code wouldn’t properly process. However after a couple hours of adjusting the wire formation I was able to successfully upload my code onto the arduino. My next milestone will be connecting the bluetooth to the mobile app and running the program smoothly!

Simon Says

My starter project was a Simon Says simulation game, which required the builder to have basic soldering, electric, and construction skills. I began by practicing soldering techniques in order to maximize efficiency and make sure I stayed safe while assembling my project. I then researched all the parts of my the game to fully understand how each connection was made. I learned that capacitors are devices used to store electric charge, working simultaneously with the 10k resistor to regulate current throughout the system. The microchip was basically the brain of the game, containing the code programming the LEDs to light up in random patterns. Throughout the building process I ran into a couple challenges. The first was not completely connecting the wires through soldering, resulting in the LEDs not lighting up properly. The second challenge was accidentally soldering a jumper between two legs, resulting in the game short circuiting.  I had to desolder by using a copper strip to separate the metal parts. This was a great start project for me because I wanted to practice soldering and also get an introduction to basic electrical and mechanical skills.

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