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VR Interfaces: iSense


Overview of iSense

The iSense is an athletic device developed by a student at the University of Essex in the UK. PHd student Mohamed Al-Mulla devised the device as part of his course, and it works as a prosthetic, crossing the devide between the brain's idea of what is going on, and what the muscles are actually doing.

In other words, it is a sensory augmentation, designed to increase the natural biofeedback mechanism, and provide supplementary information that the brain is not naturally aware of. It is an external prosthetic, attached to the skin by sensors, deriving it's sensory data from electromyograpic detection of the minute electrical signals generated by the muscles as they contract. This, when coupled with a processing centre - a laptop, or smaller computing device - allows a real-time analysis of muscle fatigue, alerting the athlete of impending mechanical muscle fatigue related problems before they occur.

Thus the athlete can push themselves to the limit, but have the confidence to know their augmented sensory system will warn them of impending damage to their muscles before said damage takes place. It does not stop them from pushing that little bit harder, but lets both them and their trainers know when such damage is guaranteed to occur - when it is time to slow down or take a break if they actually wish to be in any shape to compete any time in the near future.

Two types of sensor are actually used in the iSense. A flexible electro-goniometer placed on the mid-point of the arm or leg tracks in real-time the angle of the elbow, or of the knee. In theory it could also be used to track the angle of any joint if required. This angle is continually fed into the calculations taking into account the mechanical stresses the limb is under. In addition, it measures oscillations and vibrations in the joint - a key sign that the limb's mechanics are approaching breaking point. The second sensor is a more typical array of sEMG electrodes, placed around the limb, and on the torso muscles that connect to the limb, to detect the contraction stresses and determine to what extent load is being placed on each. A final sEMG electrode placed on a bony part of the body, calibrates all the other sensors in real-time.

It sounds more complex than it is. The following diagram makes things much clearer from the athlete's perspective whilst showcasing the system in operation:

The system whlst complex, is simple from a hardware point of view. Most of the apparent complexity is in the software side of things, and so the aim is not for this to be a high-end professional athlete's workout tool, but for it to be available to the average person, including the elderly and disabled.

The first iSense prototype was created in February 2011. Work has continued, and Mr Al-Mulla is now seeking investment to make the iSense prosthetic commercially viable.


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