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Troubleshooting & Notes

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Wraith edited this page Jun 25, 2026 · 3 revisions

📋 Table of Contents

🔧 Common Issues & Solutions

Symptom Likely Cause Solution
No output in rx mode Wrong frequency, modulation, or data rate. Double‑check all set* parameters. Use analyze to find active frequencies.
tx fails to transmit Power too low; no antenna connected. Increase PA setting with setpa. Attach a proper antenna (never transmit without one).
Recording buffer is empty rec wasn't enabled before the packet arrived. Enable rec before triggering the transmission.
load / save fail No saved data in flash; flash may be full. Use save or saveraw immediately after recording. Flash has limited write cycles.
brute hangs or never succeeds Incorrect symbol time or bit length. Measure the actual timing with an oscilloscope or rxraw.
Serial terminal shows gibberish Wrong baud rate or incorrect line endings. Set baud rate to 115200, 8N1. Ensure your terminal sends LF (\n) or CR+LF (\r\n).
Device doesn't respond to commands Firmware crash or hardware reset. Press the reset button on the ESP32. Re‑flash if necessary.
playsig doesn't replay the correct signal Signal was recorded with wrong timing or modulation. Re‑record the signal with recsig – ensure the remote is close and the battery is fresh.
save / load conflict between packet and raw buffers Packet and raw buffers share the same storage area. Only one can be saved at a time. Use saveraw for raw data and save for packet data.
savesig / loadsig don't work No signal has been recorded yet. Use recsig to capture a signal before saving.
jam doesn't seem to affect anything The receiver is on a different frequency or uses a different modulation. Verify the setmhz and setmodulation match the target.
ESP32 keeps rebooting Power supply insufficient or brownout. Use a stable 3.3V supply; USB power from a computer is usually sufficient.
help command shows nothing Firmware not correctly flashed or serial connection issue. Re‑flash the binary. Check the serial port and baud rate.

💡 General Troubleshooting Tips

  • Check connections – Ensure all SPI wires are securely connected, especially GND.
  • Use a serial monitor with line endings – Some terminals add extra characters; set to "No line ending" or "LF only".
  • Log your commands – Use the Python CLI's --log option to save a session for later review.
  • Start simple – Begin with known‑good settings (e.g., 433.92 MHz, ASK/OOK, 1.2 kBaud) before experimenting.
  • Test with a known transmitter – Use a working remote to verify the receiver is working.
  • Check the antenna – A mismatched or damaged antenna can severely affect range.
  • Update the firmware – Newer releases may fix bugs or add features. Check the Releases page.

⚠️ Important Legal Notes

Radio Frequency Regulations

  • Transmitting without a license on certain frequencies may be illegal in your country.
  • VoidRecon can transmit on bands that are not license‑free in all jurisdictions – it is your responsibility to know and obey local laws.
  • Common license‑free bands: 433.05‑434.79 MHz (Europe), 902‑928 MHz (USA), 868 MHz (Europe). Check your region's specific allocations.

Jamming

  • Jamming is illegal in most countries under telecommunications laws.
  • Using a jammer to block authorised communications (e.g., emergency services, aviation, public networks) is a serious criminal offence.
  • Only use the jam feature in a shielded environment (e.g., Faraday cage) or on frequencies you own and are allowed to test.

Brute‑Force Testing

  • Brute‑force attacks on remote controls may be considered unauthorised access if the device does not belong to you.
  • Always obtain written permission from the owner before testing.
  • This feature is intended for educational and security research purposes only.

🛡️ Safety & Best Practices

Practice Reason
Use low power Start with setpa -30 and increase gradually to avoid interference and reduce power consumption.
Attach an antenna Never transmit without an antenna – it can damage the CC1101.
Keep tests short Prolonged transmission can heat the chip and drain batteries.
Avoid sensitive areas Do not test near hospitals, airports, or emergency services.
Document your tests Keep a log of frequencies, modulations, and results for reproducibility.
Respect privacy Do not use VoidRecon to intercept or disrupt private communications.

🧰 Hardware Care

  • ESD protection – Handle the ESP32 and CC1101 with care; static discharge can damage them.
  • Power supply – Use a stable 3.3V supply. The ESP32 can draw up to 500 mA during transmission – ensure your USB cable or battery can deliver.
  • Antenna – Use a 50Ω antenna tuned to your frequency. A wire of quarter‑wavelength (e.g., 17.3 cm for 433 MHz) works as a simple whip.
  • Storage – Keep the device in an anti‑static bag when not in use.

🔄 Firmware & Updates

  • Check for updates – Visit the Releases page for new binaries.
  • Backup your settings – Use save, saveraw, and savesig to preserve captured data before flashing.
  • Erase flash before updating – Use esptool.py erase_flash to avoid old data interfering.

📞 Getting Help

If you encounter issues not covered here:

  1. Check the Issues section on GitHub – someone may have already reported it.
  2. Open a new issue with:
    • A description of the problem.
    • The exact commands you used.
    • The output (if any).

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