PicBerry: Oscilloscope and Function Generator

By Russell Barnes. Posted

Cornell students use a Raspberry Pi to create Digital Oscilloscope and Function Generator.

PicBerry is a Digital Oscilloscope and Function Generator created by students at Cornell University.

Function Generators are used to create different types of electrical waveforms. They're incredibly handy when learning how to diagnose and test problems with electrical equipment.

The waveforms created by a function generator are observed using an oscilloscope.

Advitya Khanna, Jeff Witz and Danna Ma are researchers at Cornell University. They've used a Raspberry Pi to create a device that performs both tasks at once. This is ideal for learning how electrical waveforms work.

"We created an affordable Digital Oscilloscope and Function Generator that is able to plot and produce (at the same time) generated electric signals (voltage) changing over time along a calibrated scale," says the group.

See also: Cornell University: PicBerry

A PIC32 is used to create the waveform. It uses the DMA Channel to create a waveform without using any CPU cycles of the Raspberry Pi.

This leaves the Raspberry Pi free to monitor the waveform and produce a digital display and interface.

Building a PicBerry Oscilloscope

Accordingly, you control the frequency and amplitude of the waveform from the Raspberry Pi. This is then displayed back on the screen, and you can zoom in and out of the display.

"Our Digital Oscilloscope and Function Generator provides a simple, easy to use alternative,"the Cornell students explain. It "provides the functionality from both these devices for less than $50."

"Even better, you can carry our device with you in your backpack," they note. "So that you do not need to come into lab" to learn how waveforms work.

As a result of this low cost approach, you don't need much to build a PicBerry:

  • PIC32
  • Raspberry Pi
  • DAC
  • Potentiometer

"The Raspberry Pi is responsible for the plotting of data onto a desktop monitor," say the students. "The PIC32 is exploited for its real-time properties of being able to sample the ADC and generate analog functions (waveforms)."

If you want to make a PicBerry, you'll find diagrams and each component on the project website, along detailed descriptions of the components.

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