[Usmar A. Padow] put together an Arduino Uno, SD card, four line character LCD, and PS/2 keyboard. but he’s also included alternative options to go without an LCD screen by using a computer ...

At the heart of the device is a AD9833 waveform generator; with the Arduino, rotary encoder, and 16×2 LCD providing an interface ... in favor of a 5V AC/DC adapter.