Instructables
Picture of Arduino Audio Input
Send sound into your Arduino.  This Instructable will show you how to prepare audio so that it can be sampled and processed by an Arduino to make sound responsive projects and audio effects.  (This article is a companion to another Instructable I've written about building an audio output circuit for an Arduino, find that here)

Some ideas that come to mind include:

beat detection- trigger lighting effects, build a set of turntables that beat match themselves, or make a robot that dances along with the music you play for it
amplitude detection- make a simple vu meter with LEDS
frequency analysis- you could make a project that reacts to different frequencies in different ways, recognizes certain melodies, turns audio into MIDI data, or translates incoming frequencies into square waves with the tone() library
digital effects boxes/digital signal processing- check out what I did with my vocal effects box (all processing done with Arduino), lots of possibilities here: pitch bending, distortion, sampling, delay, reverb, granular synthesis, mixing, and much more...  I've provided code in this Instructable that lets you sample at up to 38.5kHz.  Here is another instructable describing how to set up a simple audio out circuit with Arduino.
digital recorder- with the addition of an SD card of course (the Arduino has very limited memory by itself), this opens up the possibility of looping large samples and doing lots of other digital manipulations to pieces of stored audio  The circuits and code provided here are compatible with SD card shields that communicate via SPI.
graphical representations of sound- Arduino oscilloscope/visualizer

Feel free to use any of the info in this Instructable to put together an amazing project for the DIY Audio Contest!  We're giving away an HDTV, some DSLR cameras, and tons of other great stuff!  The contest closes Nov 26.

Parts list:
(x1) Microphone Radioshack 33-3038
(x1) TL072 Digikey 296-14997-5-ND or TL082 Digikey 296-1780-5-ND (TL081/TL071 are fine too)  I used a tl082 in my examples
(x2) 9V battery
(x2) 9V battery snap connector Radioshack 270-324
(x1) mono audio jack 1/4" Radioshack 274-340  or Radioshack 274-252 or 1/8" Radioshack 274-333 or Radioshack 274-251
(x1) LED Digikey C513A-WSN-CV0Y0151-ND
(x1) 10kOhm potentiometer linear Digikey 987-1301-ND
(x3) 100kOhm 1/4watt resistors Digikey CF14JT100KCT-ND
(x1) 10uF electrolytic capacitor Digikey P5134-ND
(x1) 47nF ceramic capacitor Digikey P4307-ND
(x1) Arduino Uno (Duemilanove is fine too) Sparkfun DEV-09950

Additional Materials:
22 gauge wire
solder
 
Remove these adsRemove these ads by Signing Up
1-40 of 215Next »
smitadriaan made it!1 month ago

Very useful instructable thanks! Got it working pretty quickly. I decided to try and implement an auto gain adjust by replacing the 10k pot with a digital SPI pot (MCP41010-I/P-ND) and it kind of works but I am seeing a strange artificial clipping at some DC bias value. The SPI pot is powered by the Vcc and Gnd from the Adruino. Replacing the SPI pot with manual one set at the same value as the SPI pot gives a perfect full audio wave. I was testing with a 1KHz audio tone.

Photo Nov 17, 11 44 02 PM.jpg

You may be exceeding the max current of the MCP41xxx at wiper extremes, though it's hard to speculate. At any rate you could try substituting a variable-gain (VGA) op-amp like an LMH6505. This wouldn't be directly SPI controllable like the MCP, but you can tie the gain input pin on the 6505 to an Arduino analog out pin to control gain programatically.

Thanks, ended up using Programmable Gain Amp from microchip with SPI interface. MCP6S22.

Hi, I am trying to implement Automatic Gain Controller using Ardunio.

Have you implemented your "Auto Gain Adjust" ? Can you please send me the documents or necessary instructions to make this successful asap.

My mail ID: kuet0909011@hotmail.com

gkzsolt6 days ago

Hi Amanda,

Many thanks for this instructable.

What commands should I use to get the full 10 bits from ADC? I understand that it takes twice as much to read, I would be happy with a sample rate of 16 KHz. The analogRead() would be too slow, as I understand, 8 KHz is not enough.

yieldlymph1 month ago

Sorry, forgot to say before, my query is regarding the 40 (38) kHz configuration.

ybaggi1 month ago

How far don CAN i scale the clock and still use the interrupt?

Can I sample at 10k?

ybaggi1 month ago

How far don CAN i scale the clock and still use the interrupt?

Can I sample at 10k?

ChristopherH12 months ago

Hi Amanda,

First of all, thank you for writing such a detailed instructable.

If you have time and still monitor this thread, I would quite like to understand what is actually going on in the setup code and was wondering how you came up with this solution, how did you approach the problem and did you acquire all of the information you needed for configuring the uno chip from the datasheet alone or did you use multiple sources?

Thanks once again.

Sorry, forgot to say before, my query is regarding the 40 (38) kHz configuration.

Thanks

mkssnwbrd3 months ago

I am working on a similar project but can't seem to figure out how to write to an SD card fast enough, could you share your SD card code as well? I have been using the SD.h library, but it is just too slow for audio.

pierattilio3 months ago

Hi Amanda, good job for this instructable :D I would know if i can use a OPA2134PA instead of the tl072, and if yes do I have to change something of important? (i'm afraid about the amplificatiopn gain, I don't wanto to burn some arduino pin :) ). Thanks a lot

roc_933 months ago

hi Amanda

Thats a great tutorial :)

Is there a possibility to use only one battery/ power supply instead of the two 9v batterys ?

asubaşı1 year ago
What does the 47nF capacitor do?

This 47nF capacitor is called a bypass capacitor, its role is to filter out to ground undesirable AC noise that is inherent to any circuit. In this case it is important to have it here so that this noise is no mixed with the input signal. This page gives a good description of what they are and how they fit in a circuit: http://www.seattlerobotics.org/encoder/jun97/basics.html

amandaghassaei (author)  asubaşı1 year ago
helps remove noise in the input signal
pmenghani4 months ago

You have a Arduino Audio Output instructable as well....i just wanted to ask if the bits that i sent using that circuit ,instead of connecting it to a speaker i connected to this circuit,can be identified using this circuit...can i use LM358 as an OPAMP

pmenghani4 months ago

You have a Arduino Audio Output instructable as well....i just wanted to ask if the bits that i sent using that circuit ,instead of connecting it to a speaker i connected to this circuit,can be identified using this circuit...can i use LM358 as an OPAMP

when i print the incomingAudio value, i get fluctuations around 512, but when i adjust the potentiometer nothing happens. i have checked the diagram many times, and even have the same ground connections and Vin connection. have i missed something in the wiring? newbie here : )

Hey, I have the same problem, did you find a solution at all?

amandaghassaei (author)  luis_cordova1 year ago
the print function might not be fast enough to give you a lot of information about what is going on. do you have an oscilloscope?
xavierm14 months ago

hola amigo, para monitorear la salida de audio de arduino que pines usas, leo que dice el puerto D,podrias explicarme ,

LMario4 months ago

Instead of the microphone input can I use as input the signal generated by the pickup of a guitar?

flaviowd4 months ago

Can I use this idea to plug my guitar and output sound via USB or P2 to plug on my computer to use with some software like Amplitube or Garageband?

sparkyluki5 months ago

would this circuit work using and electret microphone rather than the radioshack one?

amandaghassaei (author)  sparkyluki4 months ago

yes it should work with any oscillating signal, but you might need to change the level of amplification to get it in the 0-5V range for the Arduino.

asheble5 months ago

Is it okay if i use an LM741 or LM358 opAmp?

amandaghassaei (author)  asheble4 months ago

yes

opaulyc5 months ago

Hi! Great project! I just built it, and I think it is working fine since the clipping LED functions well. I have a question... How can I add a second input audio source? What do I need to add to the last code you uploaded? My intention is to use both audio sources at the same time but with different clipping LEDs.

Thanks in advance!

amandaghassaei (author)  opaulyc4 months ago

that's a little tricky, you may have to lower the sampling rate to achieve that. It involves changing the code in the setup that puts A0 in continuous sampling mode, you'll have to get into the atmega's datasheet to find the answer. I'm not sure.

mabdulaziz5 months ago

thanks for this instructable,

If I want to send this audio signal via bluetooth using BT-Shield, do you have any suggestions what should I do?

amandaghassaei (author)  mabdulaziz4 months ago
never tried, please post it if you get it to work!
Steina5 months ago

Thanks for your great work. I'm thinking about testing a mono summer circuit before it comes to the opamp stage. However i'm a bit concerned with accidentally feeding more than 5v to the adc.. Would a simple 5v zener do the trick here, tied to the A0?

amandaghassaei (author)  Steina5 months ago

yes that would work

I can only assume because the opamp stage doesn't work with my summed output, but works with each one of my stereo signals.. I need to find an alternative solution (the summer is just a couple of resistors in line with the signal)

sniffrumble6 months ago

I made it yay! although I cannot make the output tutorial since the op amp / chip is now discontinued.... can you please update that tutorial or update where to buy the chip? Thanks!

that's a good point about the op amp, I hadn't thought of that.

super

tpoe26 months ago

I made it yay! although I cannot make the output tutorial since the op amp / chip is now discontinued.... can you please update that tutorial or update where to buy the chip? Thanks!

marxys7 months ago

¡¡excelente trabajo!! :D

1-40 of 215Next »