Arduino shield for realtime audio processing
Frequently Asked Questions
How many seconds of audio can be recorded in memory?
It depends on the sample rate and bit resolution. See this detailed guide here.
Can I sample audio in stereo?
No, the Arduino is only fast enough to process a single input signal at a reasonable sample rate. The Audio Hacker sums the incoming left and right channels into a mono signal using a summing circuit. The output of the Audio Hacker is always mono.
Which Arduino boards work with the Audio Hacker shield?
Arduino Uno, Duemilanove, Mega, and Leonardo. To use a Mega or Leonardo, you need to solder a 6-pin ICSP header on the bottom right side of the board. This header is sold separately in our store.
Does the Audio Hacker work with other boards like the Arduino Due, ChipKit Uno, or Netduino?
No, the Audio Hacker is designed for the family of Arduino boards with 5V I/O pins.
Can I store audio samples on an SD card?
No, the Audio Hacker is designed to provide high-speed access to multiple audio samples by using serial SRAM memory. It is much faster than accessing an SD card, is less complex, and allows you to read from many locations in memory without opening up different files on an SD card.
Can I upload audio files to the Audio Hacker from my computer?
Not at this time, but we may build a utility that allows you to transfer a WAV file from computer to SRAM on the Audio Hacker. For now, the way to get audio from your computer to the Audio Hacker is simply by playing audio on your computer into the input of the Audio Hacker and recording it.
Why can’t I record audio at a higher sample rate, like 44.1 kHz?
There are limits to what an Arduino can do, given its 16MHz clock speed and the speed of the ADC, DAC, and SRAM chips. See this note about performance here.
Can I store more than one sample in memory?
Yes, you can divide the memory up into chunks and store multiple samples. There are some projects on the projects page that demonstrate this. See the “Four-Sample 12-bit Sampler” project.
Can I add more memory?
If you know how to add more SRAM to the SPI bus, yes you can. Additional Microchip 23LCV1024 chips can be added to the SPI bus. You will need to use a digital pin for the SS line of each chip. The Audio Hacker uses digital pins 5-13, so you could use other pins for SS.
Will my audio samples still be in memory if I disconnect power?
Yes if you connect a 3V coin cell battery to the battery connection on the board to preserve memory contents. Keep in mind that if you disconnect power, your program won’t know where samples begin or end in memory, so you will have to record that somewhere in EEPROM or in SRAM. See the “Multi-track Sampler” project on the projects page.
Is the DJ Shield required to use the Audio Hacker?
No, not at all. But the DJ Shield makes it easier to do products that require multiple buttons and potentiometers. Just put it on top and you can easily control your projects.
Can I connect an electric guitar to the Audio Hacker?
Yes. You may need to amplify the signal by adjusting the preamp gain on the Audio Hacker. Since the output of a guitar is a mono plug, you may want to connect it to the breakout solder pads on the Audio Hacker input instead of the 3.5mm jack.
My Audio Hacker doesn’t work. What should I do?
Before you contact us, make sure you consult the troubleshooting section of the build instructions. Try to solve the problem by using this section. If you still have problems or questions, contact firstname.lastname@example.org. Be very specific about your questions and send high-quality photos of your soldering work!