Xiaomi Yeelight 28W Round LED Ceiling Light

[Balu]

Hello guys,

I just got a "Xiaomi Yeelight 28W Round LED Ceiling Light" because it is one of the few that supports Wi-Fi (and BLE). I was hoping that it might have an ESP8266 compatible setup that'd allow me to flash it with Tasmota and have a nice dimmable - warm and cold white - ceiling lamp that can be controlled with my Node-Red setup.

So far I have not found any details on this light, but perhaps you guys can help me dig deeper.

During my teardown I found a nice aluminium plate with 240 cold white and warm white LEDs:

And below that the more important electronic board labeled as P586 LED Driver:

You can easily identify the power supply part and the two (WW/CW) mirrored circuits driving the LEDs, but the most interesting part is of course the white "Luna" board that is connected to a YEELIGHT ATENNAV1.2 board. The two main chips on that board are marked with "mediatek arm mt7697n 1707-bmal btpckv12" and the smaller "20" one with "gd hh1729 25q32csig apos758" (I had to clean that with some isopropanol to be able to read the marking). The board also is labeled with what seems to be a mac address starting with the XIAOMI Electronics CO. LT identifier (34:CE:00).

The 25q32csig seems to be a 32m-bit serial flash module, even though I can't find anything with hh1729.

The  mt7697n is an integrated 2.4GHz Wi-Fi / BT AP with an ARM Cortex-M4 and power management unit.

Right besides the white module are testing pads labeled "start", "+3.3V", "RXD", "TXD" and "AGND" which makes me hopeful that we could play around a little more.

Any suggestions on where to go from here?

     Balu

[Phil]

fraid you have already gone beyond my abilities, however there may be some millage with the ble interface as at least one xiaomi ble device has been cracked https://wiki.hackerspace.pl/projects:xiaomi-flora

[Balu]

On Tuesday, 13 February 2018 21:32:10 UTC+1, Phil wrote:

fraid you have already gone beyond my abilities, however there may be some millage with the ble interface as at least one xiaomi ble device has been cracked https://wiki.hackerspace.pl/projects:xiaomi-flora

I have digged around a little more. There seems to be a board extension for the Arduino IDE: https://docs.labs.mediatek.com/resource/linkit7697-arduino/en for this / a similar device that includes Wifi and BLE support. That might help people who are more advanced in this stuff.

In addition, Yeelight seems to have a development environment that allows you to switch all their equipment to a local network setup and use an API to control the device. I am trying to look into that a little more for now, since I don't have enough experience with Arduino et al: https://www.yeelight.com/en_US/developer

[Mike Roberts]

This is using a different processor to the ESPs so flashing is not advised.  Question then is how much procesing is done on board i.e. does it just toggle a 3v3 lines to PWM the LEDs or does it send a data string for procesing on the main board.

Closer inspection of the connections might give some clue (how many are connected and where do they go?).

If it sends PWM signals then Tasmota /ESP12F might be fitted.

Looks like a nice unit - and 27LED watts should be breathtakingly bright.

Mike

[Yuval Mondrowicz]

Hi

I cant help you, but maybe you can help me...:-)

How did you disassemble the lamp??

I want to separate the white metal frame and paint it in a different color.

Wondering if there is any tutorial explaining how to do this that you can point me to.

Thank you!!!

[Yuval Mondrowicz]

[Balu]

Hey Yuval,

On Tuesday, 12 June 2018 10:29:38 UTC+2, Yuval Mondrowicz wrote:

How did you disassemble the lamp??

I want to separate the white metal frame and paint it in a different color.

Wondering if there is any tutorial explaining how to do this that you can point me to.

Not a tutorial, but you can just carefully pry the two metal parts apart. I have used a plastic tool to get a small space between the parts and then was able to take them apart. Since you are going to paint them anyway, you probably don't have to be as careful as I was to not scratch off the paint.

[Glenn Chapman]

Balu,

Did you see this when you were looking for your Xiaomi Yeelight   http://sonoff.itead.cc/en/products/appliances/sonoff-led

[Balu]

Hey Glenn,

On Thursday, 14 June 2018 08:47:04 UTC+2, Glenn Chapman wrote:

Did you see this when you were looking for your Xiaomi Yeelight   http://sonoff.itead.cc/en/products/appliances/sonoff-led 

Yes, but the lamps they are showing seem to be just design examples. To me it looks like they were just trying to sell the LED strips plus controller and if you click on "Buy Sample" the Sonoff LED- WiFi Dimming LED Pack is discontinued.