Recently I've been posting a lot of projects that use an 8 bit resistor ladder digital to analog converter (DAC) and an Arduino to make sound. (see the Arduino vocal effects box, the Arduino drum sampler, and my audio output tutorial). The technique I've been using to make these DACs is very simple, it requires only a handful of 10k and 20k resistors wired together into a network. But the convenience comes with a price, as these DACs end up a little noisier than I would like at times. So I decided to buy a specialized IC that will be compatible with all the code I've already written for the resistor ladder DACs, but uses highly matched resistors to reduce noise. When I looked on Digikey for such a DAC, I found the TLC7528, a dual output 8 bit DAC IC. The dual output capability of the chip interested me a lot; while it is easy to set this chip up with one permanent output, it also gives you the option of toggling between two isolated output pins, making it fairly straightforward to set up a 2 channel audio output with a relatively small amount of additional effort/hardware setup/Arduino data pins.
In this instructable I'll show you how to use the TLC7528 with the Arduino to output stereo audio. Stereo audio means 2 independent channels of audio. Stereo audio is especially fun when sent to headphones because you can achieve some interesting auditory effects since each ear is hearing its own independent channel of sound, some ideas include:
"3D audio" spatial effects- by adjusting the filtering, amplitude, and phase of two channels of audio you can simulate the experience of sound directionality, making a sound source seem to originate from a precise location in the space around you, here's a great example
binaural beats- by sending two sine waves of similar -but unequal- frequencies to headphones (one to each ear), you will hear a pulsating beatnote that is thought to induce relaxation and other meditative effects. Here's an example.
panning- change the relative amplitude of a sound source in each channel of the stereo mix. This effect is simple, but can be really cool sounding, a great example is in the bridge of Led Zeppelin's Whole Lotta Love (listen to it with headphones!)
(x1) TLC7528 Digikey 296-1871-5-ND
(1x) Arduino Uno Amazon
(1x) usb cable Amazon
(1x) breadboard (this one comes with jumper wires) Amazon
(1x) jumper wires Amazon