FlexVolt: An affordable, open-source EMG biosensor.
FlexVolt: An affordable, open-source EMG biosensor.
FlexVolt measures electrical signals in your muscles. Educate, monitor fitness or physical therapy, or create body-machine interfaces.
FlexVolt measures electrical signals in your muscles. Educate, monitor fitness or physical therapy, or create body-machine interfaces. Read more
About this project
FlexVolt can now be pre-ordered on our webstore!
We are preparing the first production run now and we expect to be able to start shipping the FlexVolt sensors by early April, if not sooner.
Thank you to all who supported the FlexVolt Project. Though we did not reach our funding goals on kickstarter, your feedback and interest has given us the momentum we needed to get FlexVolt off the ground.
We have new wireless (Bluetooth) rewards available! And the T-Shirt designs are in (see below).
Capture biosignals of your muscles moving and flexing with your computer! FlexVolt makes EMG technology, generally only used by medical professionals and costing thousands of dollars, user-friendly and affordable. Use your biosignals to evaluate progress in physical training or therapy; compose music; control your mouse or lights in your house; teach students about biosignals, measuring data and comparison of different inputs; whatever your imagination can come up with!
FlexVolt can be used as a a tool to improve your body, as a new creative input, or as a fun way to teach students about biomedical science and data collection.
What is FlexVolt?
FlexVolt is a biosensor, similar to an Electromyograph (EMG), with the ability to measure the tiny electrical signals (microVolts) generated across your muscles when you move or flex. EMG systems typically cost thousands of dollars and are usually found in medical settings, making the technology inaccessible to most of us for home or educational use. With FlexVolt we are making EMG technology user-friendly and affordable.
FlexVolt will come in 2-channel (standard) 4-channel (deluxe) and 8-channel (Mega) packages that connect directly to your computer using an attached USB cable, or Bluetooth for the Bluetooth rewards, to make it easy for you to view and capture your biosignals. FlexVolt will connect to your muscles using sticker electrodes and pinch leads, similar to the electrodes and leads used for heart monitoring. The FlexVolt Arduino Shield has 2 channels and passes measured signals to the Arduino.
What Can You Do With FlexVolt?
Once you capture your biosignals with your computer, we are developing open source apps that allow you to do things like:
EDUCATE / RESEARCH
- Take advantage of our educational materials!
- Teach students about biosignals, measuring signal amplitude and frequency, and comparing signals between muscles or students
- Filter, process, graph, store, and output data to tables or figures.
PHYSICAL THERAPY and TRAINING
- Evaluate progress in physical training or therapy, and motivate yourself or others with muscle-controlled physical therapy games like the snake game in our KickStarter video.
- Design workouts with live feedback, including rep or total work output goals.
- Compose music and direct sound or light shows by moving and flexing
- Do something completely different that we haven't thought of yet - We can't wait to see it!
- Speakers, motors, lights, your computer mouse, a remote control helicopter, your toaster, or a room full of musical instruments like Terry Crews (click for video).
The computer apps we have already developed include abilities to
- Visualize the amplitude and frequency spectrum of muscle signals.
- Freeze frames and save images or data
- Control a computer mouse
- Play a mouse-based game using muscles (Muscle Mouse - see kickstarter video)
- Customize and track workouts
Why We Need Your Help
We have working PCB prototypes for both USB and Arduino Shield versions of FlexVolt. We have designs we've refined over months of testing, multiple suppliers lined up for each component, and beta versions of all firmware and many cross-platform software apps already developed. Now we need the support of interested educators, fitness buffs, artists, scientists, hackers, and technology hounds like you to transition from prototype to production model and make FlexVolt a reality!
Where you come in: We need your support to build a high volume production order. The costs of manufacture and assembly only become feasible for large quantities, and this means we must have a minimum number of FlexVolts claimed before we go to production. Help us make FlexVolt affordable.
What You Get
You get more than just our gratitude for helping us kickstart FlexVolt sensors - you get the final products! Regardless of which reward you sign up for, you'll get access to the software, the instructions, the forums, and all the educational materials. We will make it as easy as we can for you to use and modify the software, and we will help you learn and share with other FlexVolt users. That's what being Open Source is all about.
USB Models: The USB FlexVolt comes packaged in an in-line electronics case, similar to some adapter housings. This means the leads and USB cable are attached to the PCB inside the housing. Simply plug the free end of the USB cable into your computer, attach the leads to electrodes on your skin, and fire up a FlexVolt app.
Wireless Bluetooth Models: Similar to the USB models in packaging, these FlexVolts also have built-in Bluetooth transceivers that connect easily to your computer or smart phone. These units also come with a rechargeable Lithium battery and a USB-battery charge controller built in. Measure you biosignals on the go! For more details, see this post.
Hacker Shield: The Shield comes as a PCB with pin headers compatible with Arduino (Uno, Mega). The raw signals and filtered signals will be mapped to analog inputs on the Arduino, and the Arduino library will allow you to select which channel(s) you read. Plug in to your Arduino and measure and use your signals without a computer, or implement custom filters using the Arduino and then pass data to your computer through Arduino serial communication.
Software apps: All software is being written in Processing, a simplified implementation of Java, which is useful for graphical output. We chose Processing because it is a relatively easy language to pick up, even for non-programmers, and it is also simple to compile for cross-platform use for PC, Mac, and Linux. The final apps will be executable files which allow users to choose and select from multiple sensors (if multiple sensors are connected), set sampling rates, sampling resolution, and measurement channels. These apps will also allow users to save settings, save data, process data, output data to plots or figures, or open saved data for additional processing.
Phone Apps: We are using PhoneGap and will port our apps for use in smart phones using Bluetooth - see the Bluetooth rewards for more details about those.
Educational Materials: Along with open-source software, we'll be releasing educators' materials, including lesson plans, how-to videos, sample data, quizzes with keys, and project ideas.
Arduino Library: We will release an Arduino library, to simplify calls to read FlexVolt Shield measurement signals.
Shipping: We are environmentally conscious and have worked to minimize the impact of our shipping on landfills. We are working with local and regional vendors, to minimize our transportation footprint as much as possible. Our surface electrodes come from a supplier just 20 minutes away, and we are working with a local company for T-shirts. FlexVolts will ship USPS using recyclable boxes and packaging paper, and biodegradable cellulose tape.
Note - For shipping outside the United States, add $5 USD for the Thank You Stickers, and $10 USD for all sensor reward levels. International items will ship USPS First Class Mail.
T-Shirt Designs: Check out our new T-Shirt designs:
There are many steps to coordinate to produce and ship the finished FlexVolts. We plan on ordering a low-volume quality control production run to ensure all steps of PCB printing, assembly, and design are to our satisfaction. We expect to be shipping USB and Arduino shield units by March, 2014. Here is a list of the steps we will take:
After Fulfillment - once we have shipped all rewards, we will focus on the user forums, to allow you to provide feedback, share ideas, and share modifications of the open source codes. We will open a web store and continue selling and supporting FlexVolt units at www.FlexVoltBiosensors.com
What We Will Do With The Money
We believe in transparency and have broken down the distribution of funding in the pie chart above.
- Note that 38% of the funding goes directly to purchasing the components (at bulk discounts!), and another near 20% goes to payment fees and shipping.
- The near 20% for development includes circuit design and analysis, PCB design, product enclosure and wiring specifications, app programming, firmware development, prototype testing, and educational material development.
- The assembly and testing (5% of the budget) will be performed in-house and includes soldering leads, USB wires, and through-hole components like pin headers, installing PCBs in enclosures, and testing each unit prior to shipping.
- The PCBs will be printed and assembled in the Northeastern United States. Even with high volume order discounts, this cost makes up 20% of the project funding.
Where We Are Now In The Design Process
We have functional PCB prototypes for the USB and Arduino Shield versions of the FlexVolt. Both were printed by OSH Park (note the purple boards!) and assembled in-house.
We have also already tested several different sensor leads, and we have selected pinch leads, such as those on the right in the image above, to make it easier to swap leads and channels.
We have chosen the PIC16 from Microchip as the brains for our sensors. We have tested the operation on both PC and Mac machines, and we are currently finalizing the beta version of the firmware necessary to handle USB communications and EMG sensing.
We have several apps already developed, using Processing, for visualization, analysis, mouse control, mouse games, physical therapy games, and exercise monitoring.
We also have Arduino code developed for use with the FlexVolt shield. The code functions currently include a two-way communications handshake, data transfer, channel selection, and sampling rate selection, all from the app running on the computer.
If we do surpass our kickstarter goal, our stretch goals might include:
- Wireless transmission: connect to a computer or smart phone via Bluetooth. (Click to see prototype)
Mobile app development: expansion into mobile phone apps, because running FlexVolt from a smartphone would be pretty sweet.
Electrode armbands: the sticker electrodes work very well, and we expect them to be a hit among students during demos in the classroom, but we have put preliminary research into alternatives to the sticker electrodes that would incorporate electrodes into an arm band for longer term use of the FlexVolt.
The Story Behind FlexVolt
The FlexVolt idea started with a desire for alternatives to the standard human-machine-interfaces (mouse, keyboard, joystick). These standards have been around, largely unchanged, for decades. The desire for a more intuitive interface led to investigations in implantable electrodes (yikes!), wearable force sensors, and ultimately biosensors to measure surface biosignals like the voltage generated during muscle flex. It was at this point that we realized there currently wasn't a sensor in that category that was both wearable, affordable, and accessible for educational or home use.
Previous experience in medical device design taught us that most bio-measurement systems are prohibitively costly, though the technology itself is often relatively inexpensive. Our experiences left us with a desire to break that mold by producing affordable bio-measurement devices for educational and home use. Our goal transformed from replacing the computer mouse to building an electromyography (EMG) sensor for under $100.
Here is where the hard work comes in. We started with the most basic questions, such as "what does the signal in my muscles actually look like when I flex?"
Next we cycled through many iterations of circuit design and analysis, as well as software development, to get to a working prototype and visualizer that was both functional and user friendly.
Now came the details. We had to take our bulky, ugly, but completely functional prototype and redesign the circuitry and hardware for miniaturization AND economy. After many trade studies and economic analyses, we have zeroed in on a design for a sleek device that will fit into a small adapter cable housing, for the USB model. Our design even comes in well below $100! But only for high-volume orders.
What's next? Now we need your support to make FlexVolt a reality!
The FlexVolt Team
Brendan Flynn, Creator. A mechanical engineer by training (Mississippi State University), I quickly transitioned into biomedical engineering. I gained experience in tissue engineering and biomedical device design while earning my PhD at Northeastern University, and then worked in cancer research and custom medical sensing system development and testing as a post-doc at Dartmouth College.
I also became interested in electronics several years ago, and after ordering an Arduino kit from Sparkfun, I was hooked. I've since expanded to automation, PCB design, stand-alone microcontrollers, and FPGAs, picking up the necessary programming and hardware skills along the way.
I am passionate about science and education, and I hope to see FlexVolt being used to teach kids about their biosignals!
Electrical Engineer - We have an electrical engineer adviser to help with oversight of the circuit design, PCB layout, and communications firmware for USB and Bluetooth versions.
Invaluable and patient communications manager - The project has benefited greatly from her editing skills, including the video and this page.
We have an experienced app developer willing to help should we meet the stretch goal of FlexVolt apps for mobile devices.
We have several willing helpers lined up for the in-house assembly, testing, and packaging of FlexVolt rewards.
Credits and Attributions
Kickstarter Video Music:
Risks and challenges
We have experience making custom electronics and understand the potential pitfalls in each step of the process. We recognize that complications always come up, and have put in the time up front to plan properly so that we can handle those complications when they arise.
We have backups for parts, suppliers, and PCB printing and assembly and we have already connected with suppliers and assembly services to walk through each step in the process and establish realistic understandings of what can and cannot be done. If needed we can handle production and assembly of 3000+ units. We will not be left hanging without a crucial part or step in our production process.
We plan on an initial low-quantity run for PCB testing and quality control purposes. We are hoping to start shipping USB units and Arduino shields by February, 2014, but have conservatively listed delivery dates as March, 2014.
We already have much of the software and firmware developed, and should have reliable beta versions prior to the end of the year. All FlexVolts will ship loaded with firmware and apps can be updated through our website at any time. After shipping, we will rely on all of you to provide more in-depth feedback and input for customized apps, via user forums and developer forums on www.FlexVoltBiosensor.comLearn about accountability on Kickstarter
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