3. Windows & Android Applications

A key issue with many of the available commercial functional electrical stimulation (FES) devices is user interface. The devices have to be adjustable for two reasons:

1. Differences between users - For different users, various waveforms and activation settings may be more comfortable or effective. Better adjustability means that the same device can be useful for many types of users.
2. Adjustment over time - Since FES fatigues the targeted muscle more quickly than using the muscle naturally, FES devices have to be adjusted throughout the day as the user walks and uses the muscle.

To solve these issues, we created Android and Windows applications to adjust the device settings quickly and easily, while current devices suffer from frustrating user interfaces and time consuming adjustment. The applications are shown below.

The applications allow the user to enter settings to adjust the stimulation waveform in order to make it more comfortable or effective. To use the applications, you first pair the FES device with your Android or Windows device via the operating system. Once it's paired, you can open our application and click the "Setup Bluetooth" button to connect with the FES device. This connection process typically takes less than a second (although it varies by device, OS version, etc). Once the application has connected, the user presses a button on the FES device to put it into "Bluetooth Ready" mode and can then enter their desired settings in the application and click the send button. Adjusting the FES settings with our application takes only seconds.

When the user clicks send, the following process occurs:

1. Data validation - The application checks the user-entered values against predetermined acceptable safe ranges. If any of the values are not reasonable, the user receives an error message and the values are not sent.
2. Transmission - The application sends the values by changing them to other characters so that the values can be received correctly by the character-based HC-06 Bluetooth module, which interprets the information that it receives as ASCII character codes.
3. Receiving - The HC-06 Bluetooth module receives the data and transfers it via serial to the Arduino Due. The Due then does the same data validation as the application in order to check for errors during transmission. The new settings are then ready to be applied.