sound input

Do you know if there is some way to interpret incoming sound in Arduino?

I explain the question: I want to make a self working installation based on a DVD player and I want to put some sound signal on the .1 canal as to be interpreted by arduino to do some actions (led indications, servos moving etc.)

Have somebody an idea to do that?

It would be possible to use either an old modem chip or even some 567 chips to construct a decoder that interprets one frequency as a logic 1 and another as a logic 0. Then it would be possible to use a series of frequencies to serially send arbitrary commands.

Doing frequency analysis of analog data directly is probably outside the capabilities of any microcontroller for anything over a 200-300Hz. You need a Digital Signal Processor (DSP) for all but the simplest signal processing algorithms.

If it were me I'd build a serial stream decoder using two LM567 chips and the arduino. They are very simple to work with, cheap to buy, and using say a 1200Hz and 2400Hz signals for 0 and 1 and some timing to account for serial pulses could allow for very sophisticated audio control. Software like Audacity would make it easy to create the control sound files.

I just had another thought. You could use one of the examples around that interpret morse code and use a morse code sound stream to send the commands to the arduino.

Hello, Thank for the quick answer. I will try your propositions. My tought was more like your morse proposition, not analysing the audio but use the LFE chanel to send loud sound and nothing and just analyse that. Any idea for that? Thank you


what @wandrson describes should work fine for you: this is actually the way the old slide dissolve synchronizer units used to work. you would record a tone on a cassette, and the slide sync unit would decode this tone and trigger a transition.

If you build a 555 oscillator/NE567 decoder combo on breadboard, you will have all you need. Get them going properly, so that the 555 generates 1Khz or something, and the 567 decodes it. Then disconnect the 555 output and connect it to the audio recorder (or DVD in this case) input. Connect the NE567 to the Audio out and voila, you can decode the tones on the DVD audio track. Alternately you could just geenrate the tones in Fianl Cut Express or similar video editing software, and then decode them with a 567 circuit like this one.


Thank you for the valuable informations, I will by a 567 microchip (NE (0,8 euros) or LMC (2 euros) ?) and try with a tone signal place in my software. I will give you news about it.


the LMC567 is the more expensive, low-power version of the chip. The NE567 is the standard, and cheaper, version.