anfractuosity / flipperscope

Attempt at an oscilloscope application for the flipper zero

flipperscope

To compile and install

cd flipperzero-firmware/applications_user
git clone https://github.com/anfractuosity/flipperscope.git
cd ..
./fbt DEBUG=1 VERBOSE=1 fap_scope
./fbt launch_app APPSRC=applications_user/flipperscope

Alternatively the binary can now be installed from https://lab.flipper.net/apps/flipperscope or the Flipper Mobile App.

Provide signal to pin 16/PC0, with a voltage ranging from 0V to 2.5V and ground to pin 18/GND.

Press the 'ok' button (button in the centre of joypad) to pause/unpause the waveform display.

Demo showing three different waveform types from a signal generator.

Also see Derek Jamison's demonstration of this app as well as other interesting projects.

Measurements

• Measures frequency of waveform in hertz
• Measures voltage: min, max, Vpp

Processing captures

You can use the following simple Python script, for processing the captured waveforms, from flipperscope.

import matplotlib.pyplot as plt
import numpy as np
import struct

fig, ax = plt.subplots()
data = open("Sine.dat", "rb").read()
y = [(float(x[0]) / 2500) * 2.5 for x in struct.iter_unpack("<H", data)]
x = np.arange(len(y))

ax.plot(x, y, label='Voltage')
ax.set_xlabel('Sample')
ax.set_ylabel('Voltage / V')
ax.set_title('ADC Voltage')
ax.set_ylim([0, 2.5])
ax.legend()
plt.show()

To Do

• Customisable input pin
• Trigger type mode
• FFT
• ...

Inspiration

• For GUI menu system, used code principles from weather station and signal generator apps
• STM32 DMA example
• VREFBUF information - https://community.st.com/s/question/0D53W00001awIlMSAU/enable-and-use-vrefbuf-for-adc-measures
• Relocating vector table - https://community.nxp.com/t5/i-MX-Processors/Relocate-vector-table-to-ITCM/m-p/1302304

flipperscope's Issues

Improve displaying of waveforms

We have to currently wait for the whole buffer to be filled, which is 128 samples. For long
time periods, e.g 1s time period, that would be 128 seconds before display is updated.

Compile Issue

Latest firmware update caused compile issues... I made some changes to get it to compile, but if these aren't used, can they be removed?

RogueMaster/flipperzero-firmware-wPlugins@f7dcf69

Flipper crashes

The flipper crashes, sometimes when measuring, sometimes just after using the "run" function. I don't know if that's important but it crashed many times in a row when measuring 90hz at 1ms. Using it on the unleashed firmware. It is possible to use it, sometimes it doesn't crash for sometime. After rebooting, flipper shows: "MPU fault, possibly stack overflow". Anyway, thank you for making this cool application.

Increased sample rate

I tried to use it for some signal debugging and experienced that the resolution is a bit low for higher speed signals. (~600KHz)
If you could increase the maximum sample rate to the theoretical limit of 4.26MSamples per second or even 7.11 with lower resolution this would help a lot. Also introducing some lines to see the time resolution would be great.
After all, amazing work you've done so far, the tool is great!

Capture waveform

Need to add the ability to capture waveforms to the SD card