FAQ
TL;DR: Over 150 Tuya/Beken devices already work with OpenBeken [Elektroda, p.kaczmarek2, post #20351359] “No hardware modifications are required” [Elektroda, p.kaczmarek2, post #20537263] to read power on the CBU-based 6-in-1 meter after flashing. Follow the backup-flash-calibrate routine to avoid data loss.
Why it matters: You can turn a cloud-locked meter into a fully local, Home-Assistant-ready sensor in under 10 minutes.
Quick Facts
• Chipset: BK7231N (CBU), 32-bit @120 MHz, 2 MB flash [Tuya CBU DS].
• Meter IC: BL0942, 0–65 A, 0.1 mA resolution (SPI mode) [BL0942 DS].
• Supported firmware: OpenBeken ≥ 1.17.0 with BL0942SPI driver [Elektroda, p.kaczmarek2, post #20535543]
• Typical post-calibration accuracy: ±1 % for power and voltage [BL0942 DS].
• Flashing time: ~35 s at 921 kbit/s using hid_download_py [Elektroda, p.kaczmarek2, post #20347216]
What hardware is inside the Tuya 6-in-1 single-phase energy meter?
The main board carries a Tuya CBU module (Beken BK7231N Wi-Fi MCU) and a BL0942 energy-metering ASIC wired over SPI. Power is derived via a DP2525 buck converter, and current is sensed with a non-intrusive coil around the live conductor [Elektroda, deanfourie, #20350304; p.kaczmarek2, #20356896].
How do I back up the original Tuya firmware?
- Connect a USB-TTL adapter to CBU RX1/TX1/GND/3V3.
- Run
python uartprogram mybackup.bin -d /dev/ttyUSB0 -r -s 0x0 -l 0x200000 [Elektroda, p.kaczmarek2, post #20347216]
- Power-cycle the meter when prompted. File
mybackup.bin now holds the 2 MB image.
Which tool and binary should I use to flash BK7231N (CBU)?
Use hid_download_py; bkWriter 1.60 fails on BK7231N [Elektroda, p.kaczmarek2, post #20347216] Download OpenBK7231N_QIO_x.xx.xxx.bin from the GitHub releases page [Elektroda, p.kaczmarek2, post #20347327]
How do I enter flash mode without a CEN pin?
Start the write command, then quickly power-cycle the board; the bootloader enters UART mode automatically [Elektroda, p.kaczmarek2, post #20347521]
How can I find the USB-TTL port in Linux?
Run dmesg | grep tty. A CH341 adapter reports as ttyUSB0 when attached [Elektroda, deanfourie, post #20347438]
Where do I get the OpenBeken binary for BK7231N?
What command starts the BL0942 power-meter driver in SPI mode?
Add startDriver BL0942SPI to Short Startup Command and reboot. Readings appear instantly in the UI [Elektroda, p.kaczmarek2, post #20535543]
Why do I see “bad checksum FF wanted 8D” after reboot?
The BL0942 sometimes returns a stale frame on first poll; OpenBeken retries and recovers. Measurements still publish correctly [Elektroda, alexlimbeck, post #21328576]
How do I calibrate voltage, current and power?
- Connect a known 60 W load and verify with a trusted multimeter.
- Open Web-App → Tools.
- Enter measured values in VoltageSet, CurrentSet, PowerSet fields and press Apply [Elektroda, p.kaczmarek2, post #20535564]
How can I publish readings to Home Assistant over MQTT?
Set MQTT credentials in Network → MQTT. Example YAML:
sensor:
- platform: mqtt
name: "Meter Power"
state_topic: "obk_meter/POWER/get"
unit_of_measurement: W
Channel numbers map to topics like
obk_<MAC>/<chan>/get [Elektroda, p.kaczmarek2, post #20355143]
Can I set a static IP inside OpenBeken?
Not yet. Use a DHCP reservation on your router; native static-IP support is under consideration [Elektroda, p.kaczmarek2, post #20352389]
What should I do if two flashed devices share the same MAC?
OpenBeken’s RF tool lets you rewrite the MAC in Config → RF; give each unit a unique address, then reboot [Elektroda, p.kaczmarek2, post #20354694]
Is hardware re-wiring still required after BL0942SPI support?
No. The new SPI driver eliminates the earlier need to cut traces and cross-wire UART lines [Elektroda, p.kaczmarek2, post #20537263]
How do I update OpenBeken OTA?
Navigate to Web-App → OTA, drag-and-drop the latest .rbl image for BK7231N, wait for the automatic reboot [Elektroda, p.kaczmarek2, post #20538842]
Edge case: What if I overwrote my backup file?
You can still restore Tuya stock firmware if another user uploads their dump, but your personalised calibration and Tuya keys are lost [Elektroda, p.kaczmarek2, post #20349087]
What measurement accuracy can I expect after calibration?
BL0942 specifies ±0.5 % energy error over 1 A–40 A; field users report ±1 % after single-point calibration [BL0942 DS].
