Hello, here I will present the interior of another IoT lamp using ESP chip, RGBCW, GU10, model BKL1262, bought in a Polish mail order store. I will try to program it via tuya-convert, i.e. without opening the case, but will it work? We'll see.
This topic is somewhat related to the review of the similiar product BKL1250 which has an E27 thread and shines with only one color.
Purchase of BKL1262
I bought the product on the Polish auction site along with a few similar IoT gadgets, this particular lamp costs PLN 27 (about 6$). I found it under the name "LED GU10 - SMART WIFI - RGB - 5.5W - TUYA", although it is also known as BKL1262:
I spent more than PLN 40, I had the delivery for free.
The seller calls it "RGB", but this is the RGBCW version, so there are also two shades of white (cold and warm).
Packaging with information:
Date visible on the documents - 2019.
Teardown of BKL1262
I didn' turn it on at first - I took it apart. The glass can be removed quite easily:
You can already see the BP5778 LED driver, although it only controls the white colors (warm and cold), there are separate transistors to RGB:
You can see the WiFi module - TYWE2L:
This time I was not able to fully remove the pins properly. One long goldpin broke. Unfortunately.
The board released from the center has two interestingly mounted AiSHi 25V 100uF and 400V 3.3uF electrolytic capacitors:
TYWE2L (i.e. module with ESP8266):
Programming pads (UART, TX and RX interface, here also GPIO0) are unfortunately on the bottom of the module. If it is covered by second PCB, the module will need to be desoldered.
TL10F rectifier bridge, in the power block 10K1B2 (LDO 3.3V?), To control RGB channels (via PWM) three 2302p (probably MOSFETs).
Bottom, this qGBYL circuit is probably a step down converter (I am not seeing any 'capacitor droppers' in the IoT products these days):
The already mentioned Warm White and Cold White channel controller - BP5778:
Trying to program with tuya-convert
In the case of the twin BKL1250 (offering only warm white), the tuya-convert did it, will it also work here?
I was programming according to my tutorial:
SC3-01 SmartLife switch and uploading ESP firmware via WIFI (tuya-convert / OTA)
Unfortunately no, the software is already updated here. I received an error:
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ID: 0242416f68626d643661473931494652319fcb921dd2d6d9743f2fbe5638a3f6a3e76dd55398965b9b908ab2db0940ca66 PSK: a6cbe68237ded299d8ed90ab9a0cf0a11fe014448d35f24122057cc529249f3b could not establish sslpsk socket: [SSL: DECRYPTION_FAILED_OR_BAD_RECORD_MAC] decryption failed or bad record mac (_ssl.c:1131) new client on port 443 from 10.42.42.27:70
This is quite a known problem, you can read about it on Github tuya-convert. It is impossible to upload the firmware here remotely. You have to solder.
Simple module desoldering and programming
The module must be desoldered, because the RX / TX pads are covered by the second PCB and there is no other way to get to them.
You could use hot air, but why complicate it?
All you need is the cheapest, used soldering iron without power regulation, flux and some lead solder (Pb-free solder has higher melting point which makes everything hard, so I prefer Pb one).
1. apply flux
2. apply additional Pb tin on the pads
3. heat up all pads with extra tin together
4. the module should drop by itself
5. it is worth cleaning with a braid and also IPA pad cleaner
Some photos from the process:
Programming ESP8266 ... it was discussed many times, even by me, here:
SmartLife switch - test, interior and WiFi light switch programming
In general, I soldered only RX, TX, ground, power and IO0 (to ground) and it started, I rebooted by cutting off the power, I powered it from the 3.3V TC1264 LDO. I programmed via esptool.py. I made a backup of the firmware (I will put it at the end of the topic):
Configuration of Tasmota
The configuration is probably on the Blakadder website, but I set it up manually in my case:
The lamp works without any problems.
For comparison - a regular GU10 LED bulb without WiFi
Only as a curiosity I will show the teardown of an ordinary lamp:
The LED lamp presented here is damaged, but only two of the four LEDs burned out - if you had two of them, you could make one working.
The LED lamp is based on the BP2832K chip:
It is a constant current buck converter. The large black element with the HX inscription visible in the photos is a coil.
Do newer versions of this product also have ESP8266?
The Blakadder website also has some disturbing information on this issue:
The given date (2020) would confirm my guess that my lamp comes from an older series (2019) and is still on ESP. On the other hand, I did not verify personally what the newer parts are made of - so I only leave this information here as a quote.
Referring to the Blakadder website, I can say that this light comes from the period when the tuya-convert did not work anymore (after changing the PSK), but there was also an ESP8266 inside. I don't know if it changed after that.
In order to program it, I had to desolder the module what turned out to be very simple, the cheapest soldering iron still one with a worn tip.
Programming went smoothly and after a quarter of an hour the lamp was already controlled by Tasmota.
I am very happy with the purchase - so far, when buying WiFi RGBCW LED lamps, I have mainly found Beken (several times), BL602 (once) and M10D11 (once), and yet I need something on ESP to test my Tasmota Device Groups service code.
I hope that my topic will be useful to someone - even a similar LED lamp from this store (model WOJ14415 ) is on BK7231T / BK7231N, so if you want ESP, you know what to buy and what to avoid.
If you want to know what can be done with such a lamp, I recommend, among others. this subject: Home Assistant Tutorial - configuration, WiFi, MQTT, Zigbee, Tasmota
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