Load cells and innovation: taking the next step
At The Load Cell Shop, we’re always amazed by the innovative uses of load cells across almost every industry and market section imaginable. We’re always particularly pleased when these innovations are made by young inventors, researchers or students, helping push the boundaries of possibilities a little further.
Students put through their paces
At the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), students on the Engineering Design Projects (ES 100) capstone course create solutions for real-world challenges. It’s a concept used around the world to bring together a student’s knowledge and study into an in-depth, practical project at the end of their university course.
For electrical engineering student Seif Abou Eleinen, inspiration came when he had foot surgery.
“I was on crutches and a scooter for almost six months. When I first started walking, I was having trouble applying the exact weight percentage prescribed, which led to my recovery period to actually be longer. I wanted to design a device that would help anyone who has to go through what I did.”
Loading your bones
When load-bearing bones are injured, recovery requires gradually applying body weight over a period of time. Overloading too early can cause ligament strain or partial fractures, and prolong the recovery period.
The issue is that patients need to learn how much weight to apply, and when to increase it. The usual system of using bathroom scales along with the verbal advice of therapists is not efficient or particularly reliable.
Instead, Abou Eleinen adapted a standard hospital crutch with a feedback system that measures the force exerted and the time taken between steps. If too much force is exerted, or the steps too fast, an audio signal sounds every 30 seconds.
Abou Eleinen’s system used
“Load cells and accelerometers to measure a patient’s exerted weight and speed over gain cycles, comparing those measurements to patient-specified thresholds.”
Load cells in walking canes
Using loads cells in walking aids to analyse gait is nothing new. We’ve covered several such innovations that place load cells into walking aids such as sticks to assess the force exerted or weight applied to the cane.
What we hadn’t quite appreciated until reading a MSc thesis by Robert Boyles was why monitoring was important. Whilst 10% of the US population aged 65 and older population use a walking cane*, very few receive proper instruction in their use. Furthermore, up to 50% of users will stop using a walking aid if they develop other injuries, such as wrist strain**.
Boyles’ solution was to place sensors in the cane linked to electronics in the handle, to relay information. He placed a compression load cell at the base of the cane linked by a USB 3 cable than ran up the cane shaft to the handle. This load cell provided an accurate measure of the axial force applied when the cane was in use. Combined with Force Sensing Resistors in the handle, the cane can measure the forces at both ends of the walking aid. The data is then relayed wirelessly to be analysed.
Load cells enable low-cost solutions
A paper published in the open access journal “Sensors” details the combined use of load cells and Light Detection and Ranging (LIDAR) in a four-footed walker to monitor any imbalance and poor motor coordination.
- The problems of mounting the load cell experienced by Boyles were more easily overcome by this team by using “a dedicated plastic adapter grown on a low-cost 3D printer.”
- The data gathered was relayed by Bluetooth and analysed using a custom-made app, managed by the physiotherapist.
The authors particularly noted that due to the use of load cells, and readily available technology:
“The proposed measurement system is a low-cost prototype that can easily be adapted to existing mobility aiding devices, including standard walkers, wheeled walkers and rollators.”
Your project, our load cells
Whatever your project is, we can provide the load cells to your specifications. We design and manufacture load cells from the micro to the magnificent, and can help design systems that optimise their potential.
So, give us a call to discuss your requirements – we are always happy to help.
NOTES:
* H. Kaye, T. Kang, and M. LaPlante. Mobility device use in the United States. Disability statistics report 14. Washington, D.C.: National Institute on Disability and Rehabilitation Research, U.S. Department of Education, 2000.
** H. Bateni and B.E. Maki. “Assistive devices for balance and mobility:benefits, demands, and adverse consequences”. In: Arch Phys Med Rehabil 86 (2005), pp. 134–145.
