# PowerWalkers (TM): Saving the Environment One Step at a Time

Readers of my previous blog entry "What Light Through Yonder Flashlight Shakes?" have asked for details about the science project that caused my son and I to look into shake flashlights in the first place. Here goes.

My son's science class had the option to do either the traditional sort of science project where you take data to prove/disprove a hypothesis, or create an "invention". My son chose the latter.  The idea for the invention - which was entirely his - was to generate electricity as part of everyday activity in order to power an iPod or cell phone. He had the idea to use shake flashlights as his basic power source. He called his invention "PowerWalkers (TM)".

My job, as Dad and trained Electrical Engineer, was to help him turn the idea into reality. I thought it was a good idea overall. However, as with most engineering projects, I realized that it would not be as easy as it sounded. So I was a little aprehensive. But his confidence became contagious.

In the previous blog entry I covered the problems we had with the flashlights themselves. Those problems were unexpected. However, after solving them, the other engineering problems turned out to be about on the scale I had anticipated. We soon found that one problem was that of aligning the charging motion of the flashlights with the motion of walking: my son was very determined that they should be charged by walking, which was fundamental to his concept. As the sort of engineering compromise that one often makes in the development process, I thought it might be better to change the concept and use them like the "heavy hands" weights that walkers and joggers sometimes use to work their arms along the way. However, my son was determined to stick with his original concept. So be it: although he had originally envisioned them on the legs, we decided to just connect them to shoes with rubber bands as shown below:

The next problems to solve were the ordinary electrical engineering problems of voltage and current. After taking some basic measurements of the flashlights and researching USB's DC voltage, we determined that we would need two flashlights connected in series to provide the required voltage.

We modified the flashlights by adding a mini phono jack to the end of each one for a power connector and connecting a matching cable with mini phono plugs and a USB connector:

After doing some walking to charge it up, it was time to try it out. It really worked! However, the results still were a little disappointing. It didn't charge the iPod for long. The problem was that the flashlights simply didn't create and store enough power to do the job we were after. It was basically the same problem that the flashlights had when they were flashlights.

No matter: good scientists and engineers both young and old expect to fail more often than they succeed. Plus, a little problem like the fact that the invention more-or-less worked but wasn't really all that useful would never stop the likes of a Billy Mays (rest his soul) or a Ron Popiel; otherwise, the world would never have enjoyed Oxi-Clean, the Pocket Fisherman, or Spray-On Hair.

So, the hunt is afoot, Watson - to marketing!

Part of the school assignment for the invention was to create a "commercial", or as it's known in the trade, a 30-second informational video about the product. With time running short, we set to work on that.

The result was the three little videos below. These aren't properly stitched together into a commercial (TBD), so as you look at them, try to think of them as a single neatly edited finished spot.

In case you're wondering, it's not a coincidence that the third video is separate from the second: it's what we in the business call a "cutaway". I think we made that one using a wall-plug USB power supply, which had enough juice to actually light up the iPod. (Note that the power cord runs off the table.) Don't worry, though - marketing may be marketing, but his project writeup was completely honest about his results. For reasons I still don't understand, though, he got a "B" on the project. I wonder what grade Ron Popeil got for Spray-On Hair?

All kidding aside, I think PowerWalkers are a good idea and potentially a viable product after the engineering problems get solved. Unfortunately, my son and I don't have the time or energy to pursue commercializing the concept. However...if anybody out there wants to buy the idea from him - or even hire him as a spokesman for the Pocket Fisherman, Spray-On Hair, or that stuff Billy Mays used to sell - and would be willing to pay for his college, don't be shy about contacting us. ;-)