Smart-ifying the Home of a Quadriplegic

Team Hausm8: Sunny Singh, Aparna Sumanth, Emily Holtz, Jack McGrath, Zhihao Yang, Abigail Riesmeyer, Rhea Bhakhri

Introduction

Hello! We are team Hausm8 ― a group of 7 students at the University of Michigan with a passion for using our design and technical skills to help others. Through our involvement with the MedLaunch student organization, we’ve been able to do just that, and have had the amazing opportunity to develop some assistive tech for members of the local community with medical needs, working hand-in-hand with them along the way.

This year, our team set out to develop customized smart home technology for a community partner with quadriplegia. The road to developing our design has been full of twists and turns and ups and downs, from the many trials and tribulations to those moments of joy when we finally overcame a challenge. Come along for the ride as we recount our experience!

Meet our Community Partner

Our community partner is a young man who is quadriplegic, meaning that he has full or partial paralysis in all four of his limbs. He is currently wheelchair-bound and resides in an apartment near Ann Arbor with his service dog. In his free time, he enjoys hanging out with his dog, creating art, and playing his guitar. Throughout his daily life, however, he faces many challenges as a result of his disability, and we quickly noticed that his apartment is not particularly handicap-accessible.

The Overarching Need

After conducting some preliminary needs finding, we realized that an issue our community partner struggles with every day is that he has difficulty opening and closing the doors in his apartment. His current method to open doors includes using an elastic band and his mouth, and this process takes about 45 seconds for him to open the door and another 10 seconds to close the door. This method definitely isn’t the most convenient, considering the average time it takes to open and close a door is typically around 2–3 seconds for most able-bodied people.

Our team decided to address this issue and come up with a way for our community partner to more easily open and close both the front door and bathroom door in his apartment. Our overall goal was to develop a device that enables individuals with limited mobility and/or limited strength to open and close doors in their own living environment affordably and without any permanent installation.

Market Research

The majority of automatic door-opening and closing systems on the market are the typical handicap systems with a “press to open” button and a swing door operator, or the automatic sliding doors with a sensor, as seen in most grocery stores or public buildings. These installations are very permanent, and they cost anywhere from $700 for the cheapest swing door operator system to $10,000 for the automatic sliding door system. Moving forward with our design and prototype for an automatic door opening and closing system, we are hoping to keep all costs well below $300.

Shown above: your typical models for automated door opening/closing systems seen in public venues.

Some Initial Challenges and Design Requirements

Our client lives in an apartment building with more-than-ambiguous restrictions regarding what can be put on his walls. Therefore, it took us some time to iron out exactly what was allowed, delaying our timeline. Another challenge was ensuring that, even in failure, our project wouldn’t harm our community partner or his dog. This meant that we had to find a way to ensure that the entire mechanism wouldn’t be ripped off the wall if it was somehow triggered with the doors closed, while ensuring that our partner could manually open his doors in the event of equipment failure.

Apart from the guaranteed safety of our design, we took some time to outline all the other major requirements and specifications that needed to be considered. Firstly, to comply with our budget and provide an advantage over current market solutions, we needed an affordable design that would cost well below $300. The device would need to open the door to a full 90 degrees and do so more quickly than 45 seconds, with a target of under 20 seconds. We also needed a solution that was long-lasting but not permanent, with it being able to function without major repair for at least 2 years (the estimated time that our community partner will remain in his apartment) but being accessible and fully detachable from the wall. As our partner can’t exert much force, any control buttons for our mechanism needed to require less than 1 N of pressure to activate touch-sensitivity. Lastly, our design needed to be lightweight, and we aimed to keep everything under 3 lbs.

Our Solution and Development Process

In order to create a robust, reliable door-opening mechanism that was low-cost and required no permanent hardware installations, we needed to use off-the-shelf hardware for the most part to minimize material costs. The Arduino interface and motors from online vendors made perfect sense for this reason; we decided to base our entire mechanism off of the Arduino interface as its open-source software/IoT device platform allowed us to efficiently put our code together while interfacing with a variety of hardware devices.

Our final solution involves two Arduinos, two WiFi modules, motors, and spools with kevlar thread. The idea was to use the Arduino interface to activate the motors and rotate our spools of thread (with the other side of the thread being attached to the doors), pulling the doors open. We taped off the latch mechanism so that the doors could simply be pulled open, with the manual door-locking mechanism still intact for safety. As the front door was significantly heavier than the bathroom door, we used a stepper motor to pull open the front door and a servo for the bathroom door. In order to run the motors, we needed an external motor shield and power supply.

(Our very first prototype, when we got the servo and stepper motor working for the first time!)

At first, when considering ways to wirelessly trigger our mechanism, we tried to couple Arduino with Amazon Alexa, in order to set up a system where our community partner could ask Alexa to open/close a door and our Arduino mechanism would then carry out the action. We stuck with this idea for quite a while, but eventually realized that it had a high latency of response and the implementation was unnecessarily complex for the application we needed it for. We also realized that this solution could be a bit problematic, as anyone standing outside the front door of our partner’s apartment could potentially be able to open the door with a simple voice command. Definitely didn’t want that happening.

We then transitioned to using two NFC modules. One was connected to a wall-mounted Arduino that is connected to the motors while the other is connected to an Arduino attached to our community partner’s chair. The Arduino on his chair has a capacitive touch remote with metal buttons that require a simple touch to activate, allowing him to open and close both his front door and bathroom door with ease. With this new system, the touch-activated buttons on the chair sends a signal to the Arduino on the chair, which then communicates with the wall-mounted Arduino via the WiFi modules. The mounted Arduino is connected to the stepper motor and servo, both of which are attached to spools that rotate and pull the doors open.

As the front door is heavy enough to close automatically, no closing mechanism was needed there. For the bathroom door, we implemented a system with a weight hanging on a pulley on the inside of the door, that would be pulled up when the door was opened and dropped downward by gravity to close the door when the door was released. We also needed something that was as light as possible given that it had to be mounted to a wall, and decided to create a frame out of laser-cut wood. This kept the entire assembly light while allowing for us to precisely control the physical layout and footprint of our device.

Of course, we didn’t get everything right on the first try. None of us had worked with WiFi modules before, so lots of trial and error was needed to get them working. When we first started testing the modules, we weren’t getting any communication at all; it took us way too long to realize that we’d been using modules meant to communicate over a range of 1000 meters the entire time, which had been completely oversaturating the system (whoops). Switching to a smaller range of communication solved the problem, though, and we were back on track with our design!

What We Learned

We came into this project expecting it to take a semester at most. We slowly came to realize that a well-engineered project would take time, energy, and thought. We also learned that the most technically complex solution isn’t necessarily the best one. We also realized that, as college students, our schedules were dynamic. It was essential for all team members to have the flexibility they needed while getting tasks completed. By focusing more on the task at hand and not when and where meetings would occur, we ensured that our teammates were more engaged with the project and ultimately took more away from the experience.

Since the ages of our team members varied from freshman to junior and our majors included biomedical engineering, art and design, biology, and physics, we were able to apply a multidisciplinary approach to our design, building off of each other’s skills and learning/growing from the diversity of our thoughts and experiences. We’re grateful to have had the experience of working with each other, as we firmly believe a team of individuals with distinct attributes really contributes a unique aspect to problem-solving that’s unlike any other.

Conclusions and Future Plans

Due to COVID-19, we were unable to finish up our project before the end of the year, as we were unable to meet with each other, gain access to the tools necessary to finish building our design, and conduct in-person testing with our community partner. Nevertheless, we are proud of the progress we were able to make, and plan to wrap the project up over the summer and deliver it to our community partner before the beginning of the next school year.

Our immediate next step is to implement an in-line current sensor (ammeter) to monitor the current going to the motor that controls our community partner’s front door. If the current going to the motor breaks a threshold value (i.e. the motor is trying to open a closed door), we want to disengage the motor to prevent damage to the hardware and to ultimately avoid the hardware being ripped off the wall (our main concern). Once this failsafe mechanism is implemented, we just need to assemble all the pieces together into our laser-cut box, conduct in-person testing, and install everything in our partner’s apartment.

We’re excited to see the completed project come together, and eagerly look forward to the day when we can see it in action. We may have faced a number of challenges along the way, but just knowing that our design will make a meaningful difference in the life of someone in our local community makes it all so worth it.

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