Team Status Report for 3/7/26

Previously our most significant risk was actually getting the motion sensor but after working with the vendor we finally received the sensor and datasheet that we wanted and now need to make a PCB for it. So we think now the biggest risk is just receiving the PCB on time before our interim demo and making sure we have the 3D printed casing ready for all of our parts. The PCB will be completed by this weekend so it can be sent of Monday which ideally should be enough time to receive it before the demo and the 3D case has been going through multiple iterations as well to ensure all the components fit. The main contingency plan we have is if the PCB does not arrive in time we do have another backup motion sensor that we took from a mouse that is a through hole component so we could temporally wire it up to a breadboard or something just to show our design working until we receive the PCB.

There has been one change to our design which is the type of optical flow sensor. We have managed to receive an optical flow sensor with a different part number and is much smaller than the previous one we were considering. This change was necessary since the other optical flow sensors we hard to find and this was the one the vendor recommended to us. In addition, the other optical flow sensors are much bigger so with this new one would allow our pen tip to be smaller. We think the only cost we incur from this change is we will most likely need to change our pen tip size to fit the new motion sensor other than that everything else pretty much remains the same. We will just continue to experiment with the 3D pen case to mitigate this.

Here is our updated schedule: 18-500 Gantt chart – Gantt Chart

Week-Specific Items

A was written by T’sairus Beasley, B was written by Christian Cherry, and C was written by Jamari Toussaint.

Part A (Global Factors):  To address global factors, our digital pen is designed to break down the geographic and socioeconomic barriers associated with digital education and creative work. In many regions and non-academic environments, users lack access to expensive hardware like tablets or specialized displays. By utilizing an optical flow sensor and IMU inside of a pen to track movement on any standard surface like a basic wooden desk our product allows anyone with a basic, low-cost Bluetooth-enabled laptop to have access to high-quality digital tool. Furthermore, the pen’s architecture directly accommodates users who are not technologically savvy since the onboard MCU handles all the complex coordinate transformation math locally and the pen acts as an universal Bluetooth device. This means users around the world are not required to download specialized drivers, navigate complex software installations, or pay for subscription ecosystems. Our device makes digital literacy and tools globally accessible.

Part B (Cultural Factors): The transition from physical to digital mediums can often disrupt traditional methods of writing and artistic expression. To address these cultural factors, our stylus respects these by very closely mimicking the physical form factor, weight, and tactile experience of a traditional pen. In addition to this, by calculating orientation with the IMU and MCU locally and transmitting these results to the digital canvas, our stylus preserves the user’s natural handwriting style and stroke dynamics. This ensures that users are not forced to adapt their cultural writing behaviors to suit rigid technology. Instead our stylus technology seamlessly adapts to the physical habits of the user and allows their experience to feel more natural and align with the norm.

Part C (Environmental Factors): To address environmental factors, our design mitigates the issues typically associated with traditional writing. Traditional writing consumes tons of paper and contributes to negative environmental impacts such as deforestation. Our pen design eliminates the need for paper entirely and allows users to digitize their work by writing directly on any desk or table surface which are inherently reusable surfaces. Also the pen implementation reduces electronic waste by integrating a rechargeable LiPo battery and utilizing lead-free solder on the custom PCB. This helps the pen avoid the toxic metal waste generated by disposable alkaline batteries. Finally, the modular design of the pen case allow users to open the casing and replace individual components rather than discarding the entire pen if a single part fails.

Tsairus’s Status Reports for 3/7/26

This week I spent time working on fleshing out the optical subsystem and power subsystem for the design report.  I also spent some time analyzing the tradeoffs between our design choices and portraying those in tables to help better show how our design came about. For the optical subsystem,  I spent time deriving the equations for how we calculated the CPI that will be used by our pen and I finalized which optical flow sensor we will be using for our design. Here is the CPI calculation for our pen:

For the power subsystem, I spent time deriving the equations for what our power system will look like and why we chose the battery we are going with. Here is the calculations for that:

One last thing I did this week outside of the design report stuff is I spent time working with the vender of the optical flow sensor to receive the proper optical flow sensor and datasheet that we want to use for our pen. The optical flow sensor has been received and now the biggest thing to work on is the PCB for it.

My progress is a little behind because I was hoping to have the PCB done and sent off before spring break but I was waiting for the vendor to approve of me receiving the datasheet and the sensor. This minor setback should be okay since I plan on finishing the PCB today and tomorrow so it can be sent off to the fab on Monday. So my main deliverables for this week is to finish the optical flow sensor PCB this weekend and spend next week setting up our microcontroller and working on the IMU implementation for the orientation of the pen while we wait to receive the PCB.