Turn on a Motor if speaker is playing

I'm brand new to Arduino but I'm not sure how to proceed with my project.

Today I purchased the Arduino Uno. I have already created an O-Scale model railroad scene with animated figures (a 3 piece mariachi band) that become animated when a SPST switch is turned on. The motor used for this animation uses 3 volts and produces 4 RPM. The animation works well. The motor is hooked up to a 12 volt battery (0.8 amp) with a resistor to step it down to 3 volts.

I would like to add sound to the animation. I purchased the Radioshack Recording Module that allows me to record 20 seconds of sound. It uses a 9 volt battery.

Requirements: I would like the motor to run only when the Recording Module is playing back a recording (the play button was pressed).

My initial thought was to somehow see if there is voltage on the speaker wires, and if so, turn on the animation motor. Just not sure if that's how I should proceed. Also, might there already be software written for this kind of project?

This stuff sure is fun!

Jim

Your Arduino Uno has more than one output pin.

The recording module has its own button.

EDIT: I was talking to Henry_best.

charredgrass:
The recording module has its own button.

Swap it for a double pole button. One pole to control playback, the other to a Uno input pin.

KISS.
Don't need an Arduino.
Use a double pole switch, one pole turns the play, the other pole turns on the motor.
Unless you have periods of silence recorded and want them to stop while recording is running.

You could also use a 9 volt regulator so that everything runs off the same 12V supply then you would only require one pole. Will need filtering around 9Volt reg.

Tom.

TomGeorge:
KISS.
Don't need an Arduino.
Use a double pole switch, one pole turns the play, the other pole turns on the motor.
Unless you have periods of silence recorded and want them to stop while recording is running.

You could also use a 9 volt regulator so that everything runs off the same 12V supply then you would only require one pole. Will need filtering around 9Volt reg.

Tom.

Yes. I didn't spot that.
"When you've a hammer in your hand, every problem looks like a nail."