Piezo Vibration Sensor with 1M ohm resistor

Using Arduino Sensors
1

I found a sketch for Knock on the Arduino site for a vibration sensor.

This is what I have:

It calls for a 1Mega ohm resistor, which I dont have.

Then I found this sketch:

Of course there is no responsibility claim on either sketch but I inclined to think the second sketch is a bit more risky. Im unaware of how big a risk it would be to NOT use a resistor.

Anyway, is there a way to test this without a 1megaohm resistor? Could I wire up resistors of smaller capacities to make a 1megaohm resistor? Could I just use my largest one, which is a 33kohm resistor.

2

In this case the physical size does not matter as the power is so low. What you need is a total R of around 1M. This can be done by adding R's in series. Anything of above 470k will probably be ok.

Weedpharma

3

OK then I'll have to just buy a 1M because 33k would to much. 10 just to get to 330k!