FAQ 
TL;DR: For owners of 36 ft HBN RGB-WW string lights, the fix is to remove the 16-pin TuyaMCU, keep the TM1814, and reroute LED data to the ESP8266 for WLED. One expert conclusion: "remove TuyaMCU totally." This solves the case where stock effects keep running after a WB3S swap because the MCU still controls the data path. [#21106087]
Why it matters: This FAQ helps you convert a Tuya-based mains-powered light set to ESP8266 and WLED without leaving the original controller in charge.
| Option |
Original control path |
Main goal mentioned |
Thread takeaway |
| Keep BK module + OpenBeken |
Existing board logic stays intact |
Reuse stock hardware |
Suggested as already supporting this device class |
| Replace WB3S with ESP8266 + WLED |
New Wi-Fi module, board rework required |
Run WLED |
Requires removing TuyaMCU and wiring LED/button paths to ESP |
Key insight: Swapping only the WB3S is not enough. The LED effects continue until you remove the TuyaMCU from the signal path and reconnect the TM1814 DIN and button to the ESP8266.
Quick Facts
- The light set is described as individually addressable RGB-WW, not a simple single-color-per-string RGB controller. [#21105961]
- The board uses a converter to drop mains power to 5 V, while mains also continues through the cord to a pass-through plug at the far end. [#21105961]
- The LED side is reported as a 3-wire connection, and the PCB marks one important control line as DO for data routing checks. [#21105961]
- One small black IC has 8 legs total, and the larger TuyaMCU package discussed for removal has 16 legs. [#21108722]
- The original push button was traced to the bottom-right pin of the 16-pin IC near C11, so it must be rerouted after MCU removal. [#21110878]
How do I replace the WB3S in HBN 36ft string lights with an ESP8266 for WLED?
Replace the WB3S only as part of a larger board rework. The thread’s working plan is: 1. Identify the TuyaMCU and TM1814 paths with a multimeter. 2. Remove the 16-pin TuyaMCU, but leave the TM1814 in place. 3. Reconnect the TM1814 DIN and the original button to suitable ESP8266 pins for WLED control. That approach was chosen for a
36 ft HBN RGB-WW light set because swapping the Wi-Fi module alone did not stop the stock effects.
[#21108854]
What do I need to disconnect or remove to cut the Tuya MCU out of the signal path on these HBN RGB-WW string lights?
You need to remove the TuyaMCU, identified in the thread as
U4, the larger black IC with many legs. The TM1814 should stay on the board, because it is the LED driver interface that still needs a data input after the TuyaMCU is gone. In short, remove the 16-pin controller IC and then feed the TM1814 DIN from the ESP8266 instead of from the original Tuya control path.
[#21108854]
Why do the same lighting effects keep running after I swap out the WB3S module for an ESP8266?
The same effects keep running because the TuyaMCU still controls the LEDs. The thread shows that replacing the WB3S alone did not change the output, which means the Wi-Fi module was not the only device generating or forwarding LED commands. The expert response was direct: for Tasmota, and by extension this hardware change, you must remove the TuyaMCU and connect the LED data input to the ESP.
[#21106087]
How can I use a multimeter in continuity mode to trace RX, TX, and LED data connections on this Tuya string light controller board?
Use continuity mode with power fully disconnected. 1. Put one probe on
RX1 or
TX1 of the Wi-Fi module. 2. Touch the other probe to pins on the nearby ICs until the meter beeps. 3. Repeat the same process from the PCB’s
DO marking and from the button connection. That method let the thread trace GPIO1, GPIO3, the TM1814 path, and the button path without guessing from photos alone.
[#21108673]
What is a TuyaMCU, and what role does it play in a WB3S-based LED string light controller?
"TuyaMCU is a control IC that manages the board’s local logic and passes commands between the Wi-Fi module and the LED driver, remaining active even after a WB3S swap." In this thread, it is the larger
16-pin IC near U4. Its role matters because the lights kept running their original effects after the WB3S was replaced, showing that the MCU still sat in the signal path.
[#21108949]
What is the TM1814 chip, and how is it used in individually addressable RGB-WW string lights?
"TM1814 is an LED driver IC that accepts a serial data input and controls individually addressable RGB-WW LEDs, while staying separate from the Wi-Fi module and main application MCU." In this board, the TM1814 was identified on
U3 and kept for the conversion. The thread’s conclusion was clear: remove the TuyaMCU, but keep the TM1814, then reconnect its DIN to the ESP8266.
[#21108854]
Where should the TM1814 DIN line be connected when converting this HBN light controller to ESP8266 and WLED?
The TM1814 DIN line should be rerouted to an ESP8266 output after the TuyaMCU is removed. The thread first traced DIN back through the larger controller area, then concluded that the TuyaMCU must come out and the TM1814 must later be connected directly to the ESP. The exact final ESP pin was not confirmed in the posts, but the required direction was: TM1814 DIN must no longer depend on the removed Tuya controller.
[#21108854]
Which ESP8266 GPIO is best for driving TM1814 LEDs in WLED, and why should RX/TX usually be avoided for the button?
The thread does not confirm a final best GPIO for TM1814, but it suggests reading whether
TX is needed for the LED data line. It does clearly say not to use
RX/TX for the button. Instead, route the button to an unused generic GPIO that is easy to access. That avoids conflicts with serial lines already being considered for LED control and board debugging.
[#21111091]
After I remove the TuyaMCU from the board, what other changes, jumpers, or bridges are needed to make the lights work with an ESP8266?
You still need to reconnect at least two signals after removing the TuyaMCU: the TM1814
DIN line and the original push button. The thread does not confirm any mandatory solder bridge or pad-to-pad jumper beyond those reroutes. The main failure case is leaving either path disconnected: without DIN, the LEDs have no new controller input; without button rerouting, the hardware button stops being useful.
[#21109028]
How should I reroute the original push button from the removed TuyaMCU to an unused ESP8266 GPIO?
Use a small insulated wire and solder it either to the button pin itself or to the former TuyaMCU pad that carried that button signal. Then solder the other end to an unused ESP8266 GPIO. The traced button connection in the thread came from the
bottom-right pin of the
16-pin IC near
C11, so that original path gives you a practical solder point after chip removal.
[#21111091]
What's the difference between keeping the original Beken module with OpenBeken and replacing it with an ESP8266 running WLED for this kind of light set?
Keeping the original Beken module means using the board closer to its stock design, while replacing it with ESP8266 changes both hardware and firmware direction. In the thread, OpenBeken was recommended because it already supports this kind of device, but the owner wanted WLED instead. The WLED path therefore adds extra work: remove the TuyaMCU, keep TM1814, and reroute both LED data and the button to the ESP8266.
[#21106087]
Why do these HBN string lights lose their setup after a power outage or being unplugged from mains?
The reported reason is that the stock Tuya setup does not appear to retain the user’s configuration after power loss on this unit. The owner said each unplug or outage forced a fresh setup in the Tuya app, as if persistent memory were missing or not being used. That repeated reset behavior was a main reason for abandoning the original control path and moving toward an ESP8266 with WLED.
[#21106125]
What is flux, and why is it important when desoldering a multi-pin TuyaMCU from a crowded PCB?
"Flux is a soldering aid that helps solder flow, improves heat transfer, and reduces the risk of torn pads or stubborn joints on tightly packed pins." In this thread, it was treated as necessary for removing the multi-pin TuyaMCU. The advice was explicit: use flux, and adding some
Pb solder to the pins can also help when desoldering the crowded controller area.
[#21109028]
What's the safest way to remove a 16-pin Tuya MCU from a tight LED controller board without lifting pads or damaging nearby components?
Use flux, add leaded solder if needed, and remove solder carefully rather than forcing the chip. The owner planned to use solder braid with an iron because the board felt too tight for a heat gun, and that matches the thread’s caution about nearby parts. A safe process is: 1. Flood pins with flux. 2. Wick or reflow solder evenly across the
16 pins. 3. Lift the IC only when every pin is free.
[#21108975]
How can I tell whether my HBN 36ft lights are truly individually addressable RGB-WW lights and not just standard three-channel RGB strings?
You can tell from the functional description, not just the wire colors. The owner stated these HBN
36 ft lights are
individually addressable RGB-WW and that different effects run across the string, which rules out a simple all-LEDs-same-color controller. The thread also identified a
TM1814 driver, which matches an addressable LED control approach rather than a basic three-channel analog RGB string.
[#21105961]
AI summary based on the discussion. May contain errors.
