Sound Amplitude Detection (piezo)

Forum 2005-2010 (read only) Hardware Interfacing
1

Hello,

I already found some information about a project in going to do.
But there are some little, specific, questions I still have.
If someone can help me, I'll be pleased.

I need to get information about the amplitude of the sound received by a piezo mic. Just values between 0 and MAX (0 to 5 volts).
I was thinking of making an easy connection (no preamp), like this:

But instead of the KnockSensor program I'm thinking of using something like the SimpleMessageSystem (Arduino Playground - SimpleMessageSystem) to send data from the Arduino to PuraData.

My questions:

  1. Is it possible to connect a different sound source to all 6 analoge inputs?
    I know I can read out all 6 inputs in PureData, but can the Arduino handle to ammount of data, or do I need to speed down the process?

  2. What kind of resistor do I need? More specific then "in the range of the Megaohms" 1MegaOhm? 25MegaOhm?

Any help is appreciated.

Greetings

Kasper

2

Acording to the Arduino reference http://arduino.cc/en/Reference/AnalogRead

AnalogRead() takes about 100us for a reading so reading the 6 inputs can be done very fast. The limiting factor could be how fast the serial comm. to PD can run.

You could make some kind of test, trying to se how fast you can send data from Arduino to PD, and of course also check if PD can do what you want with the data.

I made a system with 16 slide pots on 2 4051 MUX IC's and i could read the 16 values and send them to a PC over serial (16 analogRead calls + adressing the MUX Ic + packaging the readings int one string) every 10ms without problems. I did not try any faster, but i think it would be possible.

3

Thanks!

10ms is fast enough, but I will try and see if it can go any faster.

K