This is my arduino-based waveform generator using a 8-bit resistor ladder DAC. It runs with a sampling rate of 65536 Hz and can create any (whole-number) frequency from 1 Hz to 30ish KHz in sine-wave, sawtooth, triangle and different ratios of square wave. My generator produces an amplified signal and also a unamplified, high-quality signal. There is a LCD built in that shows the current frequency, and also a speaker. The LCD is actually a hacked cheap pocket calculator, for which i found out how to press CE, +, = and 1 with the arduino to make the LCD show a specific number. Yes I know that this is a stupid hack :). The generator runs from a 9V battery. Two videos are shown below; one for the hacked calculator display and one for the generator itself. The Arduino software and some other files are linked below, the electronics are pretty much the same as on <a href="http://instructables.com/id/Arduino-Waveform" target="_blank">instructables.com/id/Arduino-Waveform</a>