Vibrating Knee Brace by Trish


Project Description

The intention of my final project is to build a problem-solving prototype for people who suffer from knee pains more specifically wear and tear of the joint from excessive use. As someone who has had first-hand experience with knee issues my research explored a few problems:

  • Physiotherapy which is time-consuming and expensive, with the help of this device which is intended to be an alternative (disclaimer: if recommended by a doctor) for physiotherapy for long term use as it will be a one-off purchase.
  • Running and ExerciseRunners and athletes tend to exert their bodies with the activities they do and over time they start to experience wear and tear. This device could potentially be used by people who have active lifestyles to help with knee support and rehab.
  • DrivingThere is nothing worse than having to drive when someone’s leg is in pain hence this device could potentially help ease the pain while someone is driving.
  • Discomfort ImprovementOne other way this device could be useful would be to improve the comfort of someone while they sit for long hours working, some features would include a reminder for the user if they have sat for too long in one position without stretching their knee as well as adding a pulse vibrating sensation every 30 or so minutes.

For my study, I focused my research on designing the knee brace for very mild exercise such as walking and post-workout stretches. The knee brace has four modes which are indicated by the light emitted from the NeoPixels on the circuit playground express. The brace has four DC vibration motor modules two are located on the top strap of the brace and the other two on the bottom. When the NeoPixels are red it indicates all the motors are off, yellow indicates the top motors are on, orange is for the bottom motors and green indicates all the motors are on. There is also another mode that is activated by the accelerometer feature on the playground express when someone is in motion the motors go on and off in intervals. The vibration intensity is set to a comfortable moderation so as not to cause an intensive sensation when someone is using the knee brace. To change the different modes of vibration one must press the right button on the circuit playground express.


Parts & Materials List


  1. Adafruit Circuit Playground Express (1) PART: 1528-2280-ND MFG: Adafruit Industries LLC / 3333 DESC: CIRCUIT PLAYGROUND EXPRESS
  2. Lithium-Ion Battery (1) PART: LIPO803860 MFG: Shenzhen Pkcell Battery Co. LTD DESC: LI-POLYMER BATTERY
  3. Vibration Motor Module DC (4) PART: GR-US-222 MFG: Daiko DESC: VIBRATING MOTOR MODULE DC
  4. Jumper Wires (M-F)
  5. Insulated Wire


  1. Conductive Thread PART: 1568-1804-ND MFG: SparkFun Electronics / DEV-13814 DESC: SMOOTH THREAD BOBBIN 12M (STAINLESS)
  2. Non- conductive Thread
  3. Solder Iron
  4. Knee Brace
  5. Heat Shrink
  6. Scissors
  7. Wire Stripper


Final Prototype Imagesvibrating-knee-brace

Demo Video

Development Images and Video

How it works up-close

Rapid Prototyping of Construction

In the first iteration of this prototype, the knee brace that I used had some restrictions of space and elasticity hence the circuit playground express would need added material i.e. a pocket to be placed which was not viable because the knee brace is multifunctional and can be used for intensive activities such as working out.


The second iteration was a better fit for the design I had in mind. The knee brace had good elasticity, as well as ample surface area, and was able to fit all the electronic components. However, the major issue I faced with this prototype was the wires which had to run across the knee brace but with the help of some elastic straps I added onto the brace I managed to tuck the wires away.




Circuit diagram


Code Hosted on GitHub

Project Context

Knee pain can be divided into three major categories:

During the time I would go for physiotherapy sessions to help with my grade 1 chondromalacia also known as runner’s knee I would undergo nerve stimulation using a Transelectrical Nerve Stimulator(TENS). Below is a brief explanation of how TENS inspired my design;


For my code, I was inspired by an Adafruit project the glowing LED team badge for Pokemon Go by Richard Albritton that uses the Circuit Playground to make someones own night-time safety + team spirit wearable. As it is quite difficult to show vibration on a wearable I opted to use the light emitted from the circuit playground express  NeoPixels to indicated the different vibration modes.  Another project that inspired my design idea is by Becky Stern a vibrating headband for timing meditation sessions. It uses a haptic motor controller that can execute different vibrational patterns such as waveforms, taps, clicks, fuzzes, hums, and bumps.


The idea of my device is to bridge the gap of convenience by introducing an alternative for physiotherapy that is on the go and can be used anywhere and the iTENS (see image above) does just this same job. It is a modern-day electrotherapy device that merges technology with the proven results of “TENS therapy” to provide effective and lasting pain relief via a simple medical device app. The iTENS uses a mobile app to operate an all wireless Bluetooth based electrotherapy device that is FDA-Cleared for over-the-counter use to combat pain.


Some of the challenges I experienced while working on this project include; connecting the vibrating motors to the circuit playground express as I was using three-pin motors the best option I had was to uses wires for the connection so that it is stable. Hiding the wiring was the main issue as well as placing the wires such that they do not cause distractions while the brace is in use. As a further iteration, I would perhaps look at different types of motors that require less wiring. Another challenge I faced in the initial iteration was the material I used to bridge the connection of the top and bottom straps of the knee brace elasticity is very crucial in this design which was something I came to learn later.


The circuit playground was easy to sew onto the knee brace and did not cause any obstructions while in use. The modification to bridge the top and bottom straps of the brace was a great addition. The connection used a battery hence it did not cause any obstruction with loose hanging wires and this made portability easy.

Further Study

Some things that I would like to revise in the project for further development include; changing the colour modes I used as I did not account for colour blindness in my study, perhaps the next version will use light intensity as opposed to colour. The next thing would be to have the circuit playground light up in different modes i.e. if the top motors are on then the top half of the NeoPixels light up. I would also like to build an app to help with the ease of changing the settings as well as add capacitive touch sensors instead of using a button in order to have each sensor have its own mode. I would also hope to incorporate some of the ideas from the iTENS company as well as adding more features such as heating pads and a timer to improve the efficiency of the device.


About iTENS, LLC. (n.d.). ITENS.

Glowing LED Team Badge for Pokemon Go. (2016, July 20). Adafruit Learning System.

HailiCare Health & Beauty. (n.d.). HailiCare Heated Knee Massager. HailiCare Health & Beauty.

Haptic Headband. (2015, November 25). Adafruit Learning System.

Johnson, M. I. (2007). Transcutaneous Electrical Nerve Stimulation (TENS) in Treatment of Mus. SpringerLink.

Knee Pain: How to Choose the Right Knee Brace for Your Child. (n.d.). HealthyChildren.Org.

Knee Pain Treatment, Causes, Remedies, Symptoms. (2021, February 24). MedicineNet.


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