Fearless OScope
Fearless OScope
This is a small stereo audio oscilloscope display in a Eurorack modular panel size.
The technology is Raspberry Pi Pico RP2040 plus a programmable gain front end. The display is a common 240x240 TFT module; the one used in this build is a round type but square ones will also work.
Features:
- Oscilloscope, FFT, and XY display modes
- 5 sweep speeds
- 3 gain settings
- Left, Right or Both channel display
- Eurorack panel format, 40.64mm x 128.5mm
- 240x240 color screen
- 3.5mm stereo audio LINE input
- 5V 100mA power input
Operation
Mode Button
selects the display mode.
- Press to toggle between Oscilloscope and FFT display.
Sweep Rate Knob
sets the sweep time base
- 50 msec oscilloscope sweep, 9.375 Hz FFT resolution
- 20 msec oscilloscope sweep, 23.4375 Hz FFT resolution
- 10 msec oscilloscope sweep, 46.875 Hz FFT resolution
- 5 msec oscilloscope sweep, 93.75 Hz FFT resolution
- 2 msec oscilloscope sweep, 234.375 Hz FFT resolution
Gain Knob
sets the input level.
Beware:
overloading the input may cause clipping, which results in harmonics being displayed.
Use an attenuator for modular audio levels.
- Pro Line Level 1.228V (2.456 Vpp)
- Consumer Line Level 0.316V (0.632 Vpp)
- High Gain 0.158V (0.316 Vpp)
Input Select Toggle
selecting a single channel gives a faster display update rate.
- Left for left channel only
- Right for right channel only
- Middle for both channels
Design Documents
| Schematic Diagram | Stereo Oscope schematic.pdf |
| Bill of Material | RP2040 Eurorack Oscope BOM.pdf |
| PCB Gerbers | gerbers_N704.zip |
| Mechanical | Eurorack OScope.stl |
| Source Code - Arduino | Arduino.zip |
Build Pictures
| Oscilloscope, Audio Signal | FFT Mode, Audio Signal | XY Mode, Two Sine Waves |
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Back View
Side View
Interior
