Even Better Vibes

Project undertaken in course year 2022-23 with the Stanford School of Medicine

Project Goal

Our goal was to create a device which uses vibrational stimulation to correct the gait of people with cerebral palsy

Project Motivation

Recent studies suggest that vibration may be a useful tool in treating muscle spasticity. This device will be used as a research tool in the Gait lab to investigate the benefits of vibrational cueing in patients with spastic CP.


Spastic cerebral palsy often causes weakness and spasticity in the soleus muscle. This is a muscle located in the calf, and a spastic soleus can cause many issues with a person's gait, such as insufficient push off strength and toe-walking. To treat spasticity, medical professionals often use cueing. This is the act of using visual, auditory, or physical stimulation in the attempt to train the patient to synchronize proper motion with this stimulation.

Previous class years have developed the machine learning algorithms to detect the gait and identify when to trigger vibrational motors.  The focus of this project is to miniaturize the system, make it comfortable and robust to wear, for clinical use.

The gastrocnemius and soleus muscles of the calf. The soleus are the muscles that can be weak and spastic in people with Cerebral Palsy, and are the focus of this project.

High Priority Requirements

Ethical Considerations


Our solution uses a Printed Circuit Board (PCB) which contains a gyroscope and machine learning model which can predict when the user should flex their soleus muscle.  At the right time, the system will actuate the vibrational motors.  These electronics are housed in a 3D-printed casing. The casings along with the electronics and the vibrational motors are secured to the lower calf by a neoprene brace. This brace attaches to the calf via velcro and contains sewn-in pockets for the casings and motors.

System solution

Securement system, with pocket for casing. Wires from the battery to the PCB, and wires from the PCB to the vibrational motors are fed through holes in the pockets and thin tunnels in the seecurement system. Pockets on the inner side of the mechanism hold the vibrational motors.

Enclosed device

Casing with pcb inside and wires extending out.  

System on body

System worn on the lower leg. Velcro is used to hold the system in place, with neoprene material holding the case, which provides comfort to the user. 


3D printed casings, showing screw locations, mounts for the pcb and wall thicknesses.


PCB (top) and layout) bottom shown here.  The PCB contains three motor drivers, multiplexer, and uses an Arduino Nano with a built-in gyroscope that is used with ML algorithm to detect gait. When the gyroscope is oriented in a way that corresponds with the correct phase of gait cycle, the motors vibrate accordingly. 

Sustained load setup

Test setup for applying load onto case. Starting with 0 kg, then adding 25kg at a time, up to 125kg to determine if the case could withstand the load. 

Sustained load results

Incrementally adding weight on top of the casing, the team measured external dimensions while looking for evidence of failure.  Testing up to 125kg showed the design of the casing is strong enough to withstand the full weight of a human. 

Vibration comfort test

Testing to ensure the vibration output at the motors was comfortable, and strong enough to be felt. Testing was done on 4 people, who rated the comfort on a 1-10 scale (10 extremely comfortable, 1 is painful). Results show vibration level was comfortable. Thick material could not be felt (DNF = Did not feel)

Brace comfort testing

Testing to measure the comfort of the brace on the leg. Methodology was similar to the "Vibration" comfort testing, with similar results, concluding the bracce is comfortable. 

Case temperature testing

Testing of the case temperature during operation of the system.  Temperatures seen to stay constant and below 30C requirement.

Other testing conducted

Student team

Future Work