# step generation piezoelectric system.

#### Layan_AK

Joined Mar 28, 2017
79
Hi,

I want to deign a step generation system using piezoelectric generator as in the following fig.

I need to store the power generated in battery which supplies arduino system(5v/100mA-300mA).

-How can i determine the number of piezo generator needed?
-What is the suitable type of battery for such system?
-The charging circuit ?

Regards

#### Marley

Joined Apr 4, 2016
475
<Output voltage 48V Output current 12mA>
But not at the same time. I would imagine that the piezo element will have quite a high internal impedance.
Only way to find out is to test and see.
But if you are looking for 5V at 100-300mA this is 0.5 to 1.5W. Therefore, before the charging circuit and battery you will need to get more than this power out of the piezo element(s).
First thing to do is to connect a piezo element to a load resistor, apply a force and measure the power output. [ P=V^2/R ] You will get maximum power out when the load resistance = the internal impedance.
I think you will find the power output is much less than you expect!

#### MisterBill2

Joined Jan 23, 2018
11,879
Certainly you will need to have more information about that piezo device, including POWER delivery versus voltage or current. Charging a capacitor requires both voltage and current, and how much each piezo element will deliver is not covered in that description, UNLESS this is some new material that will deliver 48 volts at 12 milliamps. In that case t would be a game changer of large proportions.
In addition, note that the claim is ZERO to 48 volts and ZERO to 12 milliamps.
There is also the question of how the mechanical power is applied to the element. THAT is by no means a simple issue. Applying the force to the whole element without breaking it will be a serious challenge.
Can you let us know who the supplier would be?

#### Alec_t

Joined Sep 17, 2013
12,808
Something else to consider is that piezo elements don't give continuous power. Even if one could generate 48V and 12mA simultaneously (which I strongly doubt) it would probably only be for a few microseconds while the element is under maximum mechanical stress.

#### MisterBill2

Joined Jan 23, 2018
11,879
Charging a battery with pulses from a piezo element delivering pulses only a few milliseconds wide does not seem like a winning contest. Look at the spark time of a piezo spark lighter..
This is a project where you really need to go through the numbers to understand what is needed. So you need to get more information about the rest of the parameters of that piezo element, That will include the force and pressure required to deliver the rated output, and the equivalent source impedance while it is generating a voltage. The statement "Resonance Impedance100 Ohms Static" is rather ambiguous, at least it does not tell me very much.
AND if it were to somehow be driven at a resonant frequency, how much power to drive it? And what might that frequency be???