Closer look at pen
Overview of device hardware
As students and as young adults, we spend a lot of our time either on the computer or taking notes in class. This puts a lot of strain on our wrists every day, without us even realizing it! Simply changing a few small habits could dramatically reduce the stress that we put on our wrist joints and preserve them for a long time to come. To help with that, we decided to create ErgoPen.
What it does
ErgoPen detects whether you are writing with too much wrist motion and informs you by displaying a score out of 100%. When your wrist posture is decreasing, the ErgoPen will light up red to warn you. If your score dips too low, it also plays a buzzing noise as a warning until you get your score back up. The feedback provided by ErgoPen allows you to maintain correct wrist posture and develop good writing habits.
How we built it
We attached an accelerometer to the end of the pen to detect the displacement that accompanies wrist-heavy writing styles. Using the raw data provided, we ran it through some algorithms we wrote to specifically look at grip and wrist sway to display on both the touch screen and the alphanumeric display. In addition to the pen, we also incorporated LED lights, speakers, and a display on the NXP i.MX7D board, flashed with Android (provided by the Android Things kit).
At the start of every ErgoPen session, we calibrate the pen to your preferred pen orientation and use it as the basis for our calculations.
Challenges we ran into
This was our first real hardware hack, so it was challenging for us to learn how to set up the hardware and connect the parts together. We also ran into compatibility issues (the first accelerometer we tried, the Adafruit 9DOF, had drivers written only for Arduino when we had Android) which took a while to solve. In addition, the wifi module of the Android Things kit stopped working, so we had to find a workaround to connect to the Internet.
Accomplishments that we're proud of
ErgoPen is the result of numerous pivots around the idea of using motion data collected from a pen to help users. Although we previously have had no experience building hardware hacks, we eventually managed to have ErgoPen accurately determine whether someone's writing motion involves too much wrist movement. The performance of our hack definitely exceeded expectations.
What we learned
We learned how to assemble the Android Things kit and assemble hardware in general (as well as some electrical engineering terms we didn't know before). This will be really helpful when we decide to do another hardware hack in the future. Before this, we always did software, but it was really fun and challenging in a different sense, getting to actually build something physically and watch the parts connect.
What's next for ErgoPen
We'd like to expand the capability of ErgoPen to not only determine your writing posture as you write, but also to detect what it is you're writing. Applications include helping users improve handwriting in addition to writing technique and transcribing notes to cloud documents.