Human Power: The new renewable power

There is an interesting invention that has come out of Simon Frasier University. If you want a video clip check this out. It is basically a knee brace that generates power as you walk. I will try to explain this for everyone that might read this.

When you step forward your body swings your calf forward. You can think of this like a swinging weight. If the energy of your swinging forward calf had to be completely stopped by your knee you would quickly wear your knees out. To stop that from happening our bodies have muscles that slow our leg down as it straightens out. You can imagine these muscles as the brakes for our legs. Again, without these muscles your knee would have to do all the stopping of the leg. This would be similar to always stopping your car with the emergency brake.

So why did I explain the way your leg works and not the device? Well you need to understand that your leg already has a brake built into it. What this new knee brace generator does is help slow your leg down at the end of the step. (This is similar to a hybrid car using the forward energy given off by a car as it brakes to charge the battery) It does this by having your leg turn a small generator ( the reverse of an electric motor). This does not create any extra effort to walk. It will not be like trying to walk in knee high water or anything like that. The only extra work your body does is carry around a few extra pounds, and that will diminish as future versions get even lighter.

Some other quick details that the article listed:
1) It generates about 5 watts of power while at a normal walk. According to my quick research on Duracell's website, a regular AA can generate about 1 watt of power for about 75 minutes. That means that this is as good as about 5 continually new AA batteries. This is actually a lot of power. According to the article 1 minute of walking could power 30 minutes of cell phone use.
2) It weighs about 1.6 kilograms (3 1/2 pounds)

So with all of this in mind what can we use it for?

The first application suggested in the article is that it could power electric prosthesis so that amputees would not have to wear battery packs. There are also a wide range of other similar medical suggestions. For example any sort of monitoring unit that a person might wear or any sort of device like a pacemaker that might require power.

Another application is of course military in nature. Soldiers could use it to power their GPS units and other handheld devices. This would mean that they would have virtually unlimited battery life and would be in less danger of falling out of contact.

The exciting applications are when you start to think about every day use. The reason many portable devices are so bulky and limited in there abilities is that they require enough battery life to be practical. Once you improve the battery life they can add many more applications.

A classic example is the IPhone. When it came out everyone complained that it could not use the internet and talk at the same time. This is something that is not possible for second generation GSM edge technology. That is why almost all new phones being offered by AT&T (the company selling the IPhone) use third generation GSM umts technology. It allows the user to surf the internet or send a video from their camera while still talking on the phone via their bluetooth. It also allows the internet to be faster. It is like going from dial-up internet to broadband. So why would Apple release a phone that is clearly inferior in its internet and data usage? The official reason is that the computer chip for umts is a power hog and it would shorten the battery life unacceptably. Until they can resolve this battery problem Apple won't release a 3G umts IPhone.

No imagine if battery life were not a problem for portable devices. The displays may be thinner, storage may be a little higher, screen size a little bigger for watching video, internet a little faster. There are also a variety of other things that may eventually be possible that will require a power source like this one. One is a shirt that has a tv built in. It is flexible screen technology and it would be like having the ipod screen built into a patch on your sleeve. If that is a little too weird for you then maybe just a shirt that can change its colour using electricity. You may also have shoes that track your running and workout stats. That would be cool.

I'd like to hear what other people think about this.