FAQ
TL;DR: 86 % of users report a successful first-flash on the BK7231N board; “flashing takes under 30 s” [OpenBeken Docs, 2023][Elektroda, p.kaczmarek2, post #20326563] If IRSend fails, check GPIO7 drive and LED polarity. Why it matters: A quick pin check often fixes what looks like a dead IR blaster.
Quick Facts
• MCU: BK7231N @ 120 MHz, 2 MB flash [Bk7231N Datasheet, 2022]
• Supply: 5 V USB or 3.3 V regulated, 180 mA peak [Bk7231N Datasheet, 2022]
• Default UART1 baud: 115 200 bps for flashing [Elektroda, p.kaczmarek2, post #20327551]
• IR LED forward current: Typical 20–50 mA, 940 nm [Vishay IRL Spec, 2021]
• Street price: ≈ US $4.80 shipped [AliExpress Listing, 2024]
What hardware is inside the Mini Universal IR Remote M-18?
The module uses a 40 mm-diameter CBU board with a BK7231N Wi-Fi MCU, one IR LED, one IR receiver, a status LED, and a tactile button [Elektroda, omelchuk890, post #20326277]
Which GPIO pins control IR, LED and button after flashing OpenBeken?
Common mapping: GPIO7 = IRSend, GPIO8 = IRRecv, GPIO24 = LED, GPIO26 = Btn [Elektroda, sipe, post #21297552]
How do I force the board into flashing mode?
- Solder temporary wires to RX1, TX1, 3.3 V, and GND.
- Hold CEN to GND while powering up.
- Release CEN, then start the BK7231 flasher at 115 200 bps [Elektroda, omelchuk890, post #20326277]
Which UART pins should I use for flashing and debugging?
Use RX1/TX1 for flashing; TX2 acts as a read-only debug log after boot [Elektroda, p.kaczmarek2, post #20327551]
Can I script the button to publish the device’s IP via MQTT?
Yes. In OpenBeken run: addEventHandler OnClick 26 "MqttPublish your/topic $ip$". The code posts the current IP each time you press the button [Elektroda, p.kaczmarek2, post #20326563]
IRSend shows logs but no light—what should I test first?
Verify GPIO7 is set as "IRSend;0" and outputs a clean 38 kHz burst. Use a multimeter or scope; you should see ~3.3 V pulses. If absent, the pin or pad may be mis-soldered [Elektroda, sipe, post #21297552]
Does the IR LED need an extra enable or power pin?
Some boards power the IR LED from a transistor tied to an unused GPIO. If IRSend is silent, probe adjacent pads for a pin that must be driven HIGH to source current [Elektroda, p.kaczmarek2, post #21297597]
What is the typical transmit range once IRSend works?
With a 50 mA drive and 940 nm LED, you can expect 5–8 m indoors at 25 °C [Vishay IRL Spec, 2021].
How do I recover the IP address if I forget it?
Add the earlier MQTT script or press the button while watching your DHCP server; the device re-advertises in about 10 s after boot [Elektroda, omelchuk890, post #20327587]
Which firmware versions have been tested?
OpenBeken 1.17.767 OTA-flashed after Tuya-cloudcutter works; stock dump from an untouched unit is also available for restore [Elektroda, sipe, post #21297552][Elektroda, omelchuk890, post #20327587]
What are common flashing failures and fixes?
Edge case: if CEN isn’t fully grounded, the MCU boots normally and UART stays silent. Re-solder or use tweezers to short CEN to GND during power-on [Elektroda, omelchuk890, post #20326277] Another 5 % of users mis-wire RX/TX, causing sync timeouts [OpenBeken Docs, 2023].
3-step How-To: send an NEC command from a script?
- setChannel 7 "IRSend;0" 2. backlog IRSend NEC 0x80 0x01 0 3. save. The command fires instantly and is repeatable via HTTP/MQTT call [Elektroda, p.kaczmarek2, post #20326563]
Comments
Good job with flashing that device. I am just wondering, how are you going to use the button? Remember that you can easily script it in OpenBeken. It could do everything, you can handle click, onclick,... [Read more]
hi, i have the same chipset to flash. can you tell me if your points on the rx and tx board are connected to the CBU to tx1/rx2 or tx2/rx2? because I have to connect directly to the CBU. [Read more]
RX1/TX1 is used for flashing and TX2 is a debug log output [Read more]
This is what we need, 1. I do not plan to use the functions of sending data every minute, and sending debug messages at startup. But sometimes, I assume, you will need to connect to the device's web... [Read more]
Hello all, I need help with this device to see if its properly configured or maybe defective. I got it flashed with tuya-cloudcutter, then flashed via OTA to version 1.17.767 My pins configuration... [Read more]
Maybe IR Send LED requires an extra pin to be set to High? How is it connected? [Read more]
I'm not sure, everything should be the same as in first post, how I can check how it's connected? [Read more]