[Sub-Ghz] Fails to replay Manchester-encoded Volpe doorbell signals at 310, 325, 433 MHz

Describe the bug.

Description

There is a wireless Volpe doorbell that I tested at 325 MHz and 310 MHz, primarily at 325 MHz.

When using the Flipper to capture raw data via Read Raw, it fails to replay them: the signal is Manchester-encoded and is static rather than dynamic.

I also tried with ProtoView, but it doesn’t always trigger.

For comparison, I have another no-name doorbell using Princeton 24 bit; it was detected correctly and everything works fine.

I examined the transmissions in URH and found that the difference between the Volpe transmitter and the no-name transmitter is that the Princeton 24 bit (Nameless_door) alternates zeros and ones.

How can this be fixed for doorbell Volpe? Please let me know if you have any time to help.

I don’t have a full SDR to analyze it as with a HackRF—only an RTL2832U TV-tuner dongle.

P.S: The “Unknown” files are those saved via ProtoView; the “Raw” files come from Read Raw.

Download File: SubGhz_Doorbell_Volpe

Reproduction

Steps to Reproduce

1. Power on Flipper Zero with the latest firmware.
2. Navigate to Sub-GHz → Read Raw.
3. Select Frequency: 325 MHz (repeat for 310 MHz if desired).
4. Press Record, then press the Volpe doorbell button.
5. Save the captured .raw file.
6. Navigate to Sub-GHz → Replay Raw, select the saved file, and attempt to transmit.

---

Expected Behavior

• The Flipper Zero should demodulate or at least faithfully replay the recorded Manchester-encoded pulses, causing the Volpe doorbell chime to activate.

---

Actual Behavior

• The replayed signal does not trigger the doorbell.
• In URH analysis, the Volpe file shows a static Manchester pattern (no alternating bits), whereas the Princeton 24-bit file alternates zeros and ones.

---

Environment

• Device: Flipper Zero

• Firmware Version: Unleashed 0.81

• Recording Method:

  • Raw files captured via Sub-GHz → Read Raw
  • Unknown files captured via the ProtoView app

• SDR Hardware: RTL2832U TV-tuner dongle (no HackRF or full SDR available)

---

Additional Information

• The “Unknown” files are saved through ProtoView; the “Raw” files are saved via Read Raw.
• URH (Universal Radio Hacker) was used to compare Manchester encoding patterns.
• The Princeton 24-bit doorbell (Nameless_door) alternates zeros and ones and works without issue.

---

Can someone advise how to adjust the Flipper Zero settings or firmware to properly record and replay static Manchester-encoded signals shorter than the typical 63 µs pulse duration?

Download Image 1 Download Image 2 Download Image 3