Welcome to RFSqueak-MK1 – an open-source project for RF spectrum analysis and Morse code communication using ESP32 and CC1101 radio modules!
This portable device combines real-time RF spectrum scanning with Morse code communication capabilities, featuring an intuitive interface with TFT display, buttons, and potentiometer control.
- RF spectrum scanning: Real-time waterfall and occupancy visualization across frequency ranges
- Morse code communication: Transmit & receive Morse between nodes with live decoding
- Button interface: Intuitive navigation with SELECT and BACK buttons for Morse keying and controls
- ST7789 color TFT display: 1.14" 135×240 for spectrum visualization and Morse text display
- Potentiometer control: Smooth frequency tuning, threshold adjustment, and menu navigation
- Low power operation: Efficient battery design for portable field use
- Multiple modes: Waterfall view, occupancy monitoring, Morse TX/RX, settings, and diagnostic pages
- MCU: ESP32 Dev Board (240MHz dual-core, Wi‑Fi/Bluetooth)
- RF Module: CC1101 Sub‑1GHz transceiver (SPI interface)
- Display: 1.14" ST7789 135×240 color TFT LCD (rotation = 3)
- Power: HW-441 3.3V regulator with 4×AA battery pack (6V input)
- Buttons: Two tactile switches (SELECT/BACK) with INPUT_PULLUP configuration
- Potentiometer: Analog control for frequency tuning and menu navigation
- Antenna: SMA connector for external antenna (433MHz optimized)
- Shared SPI bus (VSPI): SCK=18, MOSI=23, MISO=19
- Note: The TFT does NOT use MISO. MISO (GPIO19) is used by the CC1101 only.
- Display (ST7789): CS=5, DC=16, RST=17, BLK=hard-wired ON
- CC1101: CS=27, GDO0=26, GDO2=25
- Controls: BTN_SELECT=32, BTN_BACK=33, POT=34 (ADC1)
- Operating voltage: 3.3V regulated
- Current consumption: ~80–150mA (depends on display brightness and RF activity)
- Battery life: 8–12 hours typical use with 4×AA alkaline batteries
- Power distribution: Use common 3.3V rail from HW-441 regulator
- SPI connections (shared bus):
- Shared: SCK=18, MOSI=23
- CC1101 only: MISO=19
- Separate CS lines: CC1101 CS=27, TFT CS=5
- Button wiring: Connect to GPIO pins with pull-up resistors (INPUT_PULLUP mode)
- Critical: Install 0.1μF (100nF) ceramic bypass capacitors:
- Between potentiometer GPIO and GND for noise filtering
- Between CC1101 VCC and GND for power supply decoupling
- Antenna: Connect appropriate 433MHz antenna to CC1101 ANT pin
- Platform: Arduino IDE or PlatformIO with ESP32 core
- Language: C++ (Arduino framework)
- RadioLib: Advanced CC1101 control and modulation
- Adafruit GFX: Graphics primitives and text rendering
- Adafruit ST7789: Display driver for TFT LCD
- RF Spectrum Engine: Real-time frequency scanning with adjustable parameters
- Configurable frequency range and step size
- RSSI measurement and threshold detection
- Waterfall visualization with color‑coded signal strength
- Morse Code System: Complete encoder/decoder implementation
- Real-time keying with button interface
- Automatic timing detection and symbol recognition
- Configurable dit/dah ratios and gap thresholds
- User Interface: Multi-page navigation system
- Menu-driven interface with potentiometer control
- Real-time display updates and smooth transitions
- Settings persistence and configuration management
- Hardware Abstraction: Clean driver layer for all peripherals
- Debounced button handling with edge detection
- Smooth ADC filtering for potentiometer input
- Display management with efficient update patterns
Find all code and hardware files in this repo:
GitHub Repository
- Arduino IDE with ESP32 board package installed
- Required libraries: RadioLib, Adafruit GFX, Adafruit ST7789
- Basic soldering skills for hardware assembly
- Clone the repository:
git clone https://github.com/romankalyna/RFsquek cd RFsquek - Install dependencies:
- Open Arduino IDE
- Install ESP32 board package via Board Manager
- Install required libraries via Library Manager:
- RadioLib by Jan Gromeš
- Adafruit GFX Library
- Adafruit ST7735 and ST7789 Library
- Hardware assembly:
- Follow the wiring diagram for connections
- Install bypass capacitors as specified
- Connect appropriate 433MHz antenna
- Software configuration:
- Open
RFsquek.inoin Arduino IDE - Select ESP32 board and appropriate port
- Compile and upload to ESP32
- Open
- First run:
- Power up with 4×AA batteries
- Use SELECT button to navigate menu
- Start with "Radio" for basic RF scanning
- Try "Morse TX/RX" for communication testing
- Navigation: Use potentiometer to scroll, SELECT to choose, BACK to return
- RF scanning: Select "Waterfall" or "Occupancy" modes for spectrum analysis
- Morse operation: Use "Morse TX" for transmission, "Morse RX" for reception
- Settings: Adjust frequency range, thresholds, and timing parameters
- Frequency range: 300–928 MHz (CC1101 dependent)
- Default frequency: 433.92 MHz (ISM band)
- Modulation: OOK, ASK, FSK, MSK (software configurable)
- Sensitivity: ~−110 dBm typical
- Output power: up to +10 dBm (configurable)
- IF bandwidth: 58–812 kHz selectable
- Display: 135×240 ST7789 TFT, 16-bit color (rotation = 3)
- Refresh rate: ~10–50 Hz (mode dependent)
- Input: 2 tactile buttons + analog potentiometer
- Menu system: Multi-level navigation with visual feedback
- Scan rate: ~100–1000 channels/second (configurable)
- Morse timing: Auto-detect or manual (5–50 WPM)
- Memory usage: ~200KB Flash, ~20KB RAM
- Boot time: <2 seconds to operational
- Dimensions: Custom enclosure (see photos)
- Weight: ~300g with batteries
- Battery: 4×AA (6V nominal, 3.3V regulated)
- Connectors: SMA antenna, USB programming
- Project by romankalyna
- Thanks to the RF and open-source communities!
Questions or feedback?
Open an issue or contact me via GitHub.
This project uses the following libraries:
These libraries are used as dependencies via their public APIs. No code was copied directly from them.