Piezo sensors for wheel application.

Hello. I'm a newbie on this forum as well as in arduino projects.
Recently I am thinking about piezo sensor application on the bicycle wheels. I would like to put them along the rim.
My bicycle wheel parameter is 200cm, and piezo sensor takes 2cm of its size.
So actually I can glue them in parallel along wheels' rims. So if one wheel parameter takes 200cm so I can place approximately 100 of piezo sensors.
So, I can place 200 of those piezo sensors along the rims per both bicycle wheels.

As I looked on the video placed on youtube (Power from walking Piezoelectric energy - YouTube), the guy made some calculations on how many steps are needed to charge a phone battery while the insoles inside the shoes are glued with 1 piezo element inside.

He calculated that one step could generate about 92.5uJ.
So in order to charge a battery (16920 J) it is needed to take 182 million steps. That's ridiculous!

So I came up with an idea. I'm interested in bicycles so I thought if I can place them in parallel along every rim of the bicycle wheel. In my calculations I can place 200 of those piezo per both wheels.
1 piezo sensor can generate 92.5uJ as it was mentioned before. So 200 of them could generate 18500uJ per 2 meters of drive.

So I calculated that in order to charge a battery (16920 J) it is needed to drive about 914km with a bicycle.

What do you think about that?

As that guy from that video calculated in that way I still can't believe. I looked some videos around the internet and I found a bunch of information that you can charge a phone by walking (piezo sensors are glued on both insoles of shoes). And they meant that! They said you can charge a phone battery in within 1 hour of walking! How it can be possible??

Which method of calculation is right? The guy from youtube with 182 million steps for a full charged battery or other information that I found in internet that only an hour is needed??

Do you think it is useful to glue those sensors in both wheels in bicycle rims in order to generate energy and charge electronic devices?

I've noticed that some of them placed solar panels, wind power energy generators, conductive energy, but I didn't see none of the people who thought that piezo sensors could installed in both wheels in order to generate energy.

What do you think guys?

For example look at this one:

They say that only 6 hours of walking is needed to charge a AA battery.

I don't know which source of information is reliable.

outsider:
http://www.amazon.com/Pyle-PBDNC10-Wheel-Powered-Device-Charger/dp/B00S82HCY4/ref=sr_1_2?ie=UTF8&qid=1461070813&sr=8-2&keywords=bicycle+generator

You did not get a point what advice I am seeking..

I am concerned about piezo sensors, not this one..

Well, if you are looking for a sensor to generate power, why is your subject line not "Piezo power generation"?

Did you read up on how they work? They need mechanical compression and expansion to generate power. The pressure of your foot inside your shoe is a good example. But what is the pressure inside your bicycle tyre? It's probably somewhere between 80 and 100 psi. What is the pressure when you sit on the bike? About the same. What is the pressure when you ride the bike? About the same. What is the pressure when you hit a rock? About the same.

There's no change in pressure for the piezo to work with. If it worked on static pressure, like tyre pressure, then you would have the absurd situation of generating power while standing still. You know that can't happen. You could put them on the outside of the tyre but then you will lose grip and the piezos will be quickly rubbed off against the road.

For generating power from a moving bicycle, there's lots of neat little generators that run on the wheel. Buy one of them. With the right voltage converter, that should charge a phone relatively quickly, like an hour or two.

savaslt:
They say that only 6 hours of walking is needed to charge a AA battery.

Sore feet! :astonished:

The piezo will generate plenty of voltage but extremely low amperage (a couple picoamps). Comparing to a solar panel, you would need about a thousand times more surface area using piezos to generate the same power that you would get from the solar panel. Even a peltier (Seebeck) generator would be more efficient than piezos.

Linear Technology (linear.com) sells a few ICs for use with piezos. Search their site for "energy harvesting".

Also, youtube video guy is full of it. He measures the voltage from the piezo but never the amperage. Somehow he concludes that since he's using a 22uF capacitor with his circuit that it magically fills up with each step.