DIY Portable Waveform Generator (USB Powered) : 5 Steps

The Waveform Generator is divided into 3 main sections:

1) Power Supply: The USB-C provides 5V power to the Arduino Nano, OLED Display, AD9833 IC. The boost converter generates +12V, and the Schotty Diodes and Capacitors are used to make a charge pump which generates -12V to power the OpAmp.

Parts Required: 1 x XL6009 Boost Converter, 1 x Female USB-C Connector, 2 x 1uF Polyester Capacitor, 2 x Schottky Diode, 1 x 220uF Capacitor.

Note: The Capacitors and Diodes are used to build a charge pump which generates -12V for the negative power input of the OpAmp. The charge pump requires a PWM signal which is obtained from the anode of the diode on the XL6009 Boost Converter. A wire needs to be soldered to the anode of the diode as shown in the figure below.

2) Waveform Generator: The microcontroller takes input from the user using the rotary encoder and push buttons and generates the required waveform. However the signal generated comes with a DC offset and has a peak to peak voltage on only 0.65V.

Parts Required: 1 x Arduino Nano, 1 x OLED Display, 1 x AD9833 IC, 1 x Rotary Encoder, 2 x Push Buttons.

3) Amplifier: Since the signal generated is only 0.65Vpp, it needs to be amplified using an OpAmp. The opamp is configured as an Inverting OpAmp where the 100k potentiometer controls the amplitude and the 10k trimmer controls the DC offset.

Parts Required: 1 x OpAmp, 1 x 100k potentiometer, 1 x 10k trimmer, 1 x 2k Resistor, 8-pin IC Socket.

Note: The DC offset adjustment is very sensitive due to which we need to use a precision trimmer potentiometer to set the offset accurately.