Single-channel 12-bit oscilloscope built on an ESP32-S3. Samples internal ADC @ 60 KS/s and streams frames over serial, with Wi-Fi transport planned for a future revision.
| Parameter | Value |
|---|---|
| Channels | 1 |
| Bandwidth | TBA |
| Sample rate | 60 KS/s |
| Resolution | 12-bit |
| Voltage input range | 0 - 3.3V |
Current version of project is built only using ESP32-S3 DevKitC-1, with optional start/stop button and status LED. No additional hardware required. Future revision planned to include custom PCB with external ADS930E 8-bit ADC, as well as signal conditioning and coupling circuit.
Components:
- ESP32-S3 DevKitC-1
Optional components
- User button
- LED
Pinout:
| ESP32-S3 Pin | Function |
|---|---|
| GPIO1 | ADC1 CH0 — signal input |
| GPIO21 | Optional User button (start/stop) |
| GPIO4 | Optional Status LED (on/off, indicator) |
| UART0 TX/RX | Serial data & CLI (1 Mbps) |
The firmware is designed around FreeRTOS (1 kHz tick), ISR callbacks, and an event-driven Capture and Oscilloscope threads.
Data path:
- ADC1 runs in continuous DMA mode at 60 KSps. On conversion done ISR,
Capture APIcollects and converts samples to millivolts viaVoltage APIand pushes them into a ring buffer. - The Capture API posts a
CAPTURE_DONE_EVENTeveryCAPTURE_ELEMENTS256 samples (~4.3 ms). The Oscilloscope thread wakes on this event and pops these samples from the ring buffer into the frame accumulation buffer. - A FreeRTOS software timer fires at
FRAMES_PER_SECOND(every 50 Hz or 20 ms), posting aFRAME_DONE_EVENT. The thread packages all accumulated bytes, prepends a text header, and sends over UART.
Frame format:
<timestamp_ticks> <frame_number> <total_bytes>\n
<uint16_t millivoltage samples — up to 1 KB (512 samples) per chunk>
Firmware is based on PDF (Pofkinas Development Framework) hardware abstraction layer, adapted to function with ESP32-S3. A future goal is planned to support different MPUs within the same framework build.
Custom CLI commands (send over serial terminal):
scope_start - Start ADC capture and frame streaming
scope_stop - Stop capture and clear buffer
Python GUI and utility scripts in Software/. Currently the firmware is designed to be run locally via the Python app over serial. A future revision is planned where the ESP32 hosts a web interface over Wi-Fi. All rendering and analysis would run in the browser.
Oscilloscope front-end based on Python Tkinter. Features:
- Serial port connect/disconnect
- Sends
scope_start/scope_stopcommands to ESP32 - Voltage range 0 V to 5 V
- Timebase from 1 µs/div to 5 s/div
- Horizontal voltage cursor
- Delta_t markers for time-interval measurement
- Autoscale toggle
- Pause / resume frame
- Console for debug information and commands
Serial frame parsing layer. Provides an abstract FrameReader interface and a SerialFrameReader implementation. Parses the header, reads and exposes uint16_t voltage samples. Supports debug information forwarding via callback. Can also be used standalone as a CLI frame printer.
Handles waveform rendering, cursor and delta_t markers interaction, voltage range, and autoscale.
Software dependancies can be found in requirements.txt
pip install -r Software/requirements.txt
Firmware supports both CMake (ESP-IDF) and PlatformIO. Clang-format integration and file templates are provided. Auto-formatter is set up in VSCode on file save, or run manually via script.
Clang-format (PowerShell):
.\Firmware\clang_format.ps1- Currently doesn't support trigger functionalities.
- Internal
ADC_UNIT_1is limited to ~60 KS/s. Input range is unipolar 0–3.3 V, with no negative voltages. - ESP32-S3 internal ADC has known non-linearity (INL up to ±50 LSB). Readings are only usable for relative measurements.
- No FFT or signal analysis tools.
This project is licensed under the GNU General Public License v3.0. See the LICENSE file for more details.