Verify Yeelight XianYu C2001S500 support

[VoyteckPL]

Hi,
I have this lamp c2001s500. It is stated that it is untested. Which tutorial should I follow?
Thanks!

[syssi]

Could you disassemble the lamp and provide some photos?

[VoyteckPL]

Of course!
https://photos.app.goo.gl/PqsT2dfM7g3MV6599

If you could provide a detailed guide for flashing that would be awesome!

[VoyteckPL]

I look at the description, It's kind of mystery for me where to solder RX,TX, GND and 3.3V from TTL module to Yeelight ESP module?
I guess that flashing is typical, do I need additional power supply or anything else to enter bootloader mode to load up ESPhome?
Sorry, I'm not super experienced.

[syssi]

Lets start with making familiar with your lamp / mainboard. The big mainboard is called LED driver and can be ignored. We want to focus on this daugther board:

You can see here some round pads labeled as TP1, TP2, ..., TP5. You have to find all 5 test points.

In best case the meaning of each test point is already known and documented here:

https://github.com/syssi/esphome-yeelight-ceiling-light?tab=readme-ov-file#yeelinklightceil26

To be on the safe side, we will determine all points again. You will need a multimeter for this.

Ping me as soon you are ready to move on. :-)

[VoyteckPL]

1. Daughter board - identified ;)
2. TP1 to TP5 - located :)
3. Multimeter present :)

We can proceed. :)

[syssi]

This is the pin layout of an generic ESP32:

The pins around the ESP32 are labeled and we are interested in these pins:

pin1 GND
pin2 3V3
pin25 GPIO0
pin35 GPIO1 (TXD)
pin34 GPIO3 (RXD)

Make sure your lamp is unplugged / without any power. Use the continuity tester of your multimeter to measure the continuity between ESP pin1 and TP2. If it does beep we have verified GND is attached to TP2. Do this for each test point.

[VoyteckPL]

Ok test done.
It was easy for GND and 3.3V and between pin25 and TP3 but for RX and RX I couldn't get a connection between RX - TP4 and TX -TP5. TP4 and TP5 are really hardly accessible, I suppose it is easier to solder directly to ESP32 and trust that it is exactly the same chip as C2001C450.
Ok what's next? :)

[syssi]

The daughter board is connected using a pin header to the LED driver. GND and 3.3V is available here too if you don't want to use the test points.

As next step a USB-to-TTL converter is needed. If the converter is powerful you should be able to power the daugther board using the USB. Please conntext 3.3V, GND, TXD and RXD to the USB-to-TTL converter. If you open a serial terminal (115200 baud) you should see some serial traffic (log messages) of the OEM firmware.

In the past the log output did look like this: https://github.com/syssi/esphome-yeelight-ceiling-light/blob/main/logs/ceiling10-stock-firmware.txt

[syssi]

This guide should give some guidance too: https://github.com/syssi/esphome-zb-gw03/blob/main/docs/flashing.md

This device (zigbee gateway) is also equipped with an ESP32 and the guide explains how to backup und flash the ESP. Your job is done after section "Flash new ESPHome firmware" already. The Zigbee section of the guide can be ignored.

[VoyteckPL]

I have 2 different ones. Which one would you reccomend?

The first ine looks like 5v only?

[syssi]

The one with the 3.3 voltage pin.

[VoyteckPL]

Thanks. The guide looks good and quite understandable for me. I will try later to continue, I need to find a way to solder those tiny wires :/

[helgek]

@VoyteckPL because I'm not capable of soldering such things I used PCbite from Sensepeek (for me it was worth the investment because I flashed over w dozen devices). A cheaper solution are acupuncture needles. Just wanted to let you know in case you have "two left" soldering hands like me;D

[VoyteckPL]

Nice idea but too expensive for just one use 🙂 the problem is my hands get a little shaky when soldering so small things so I need to be extra careful (or maybe have a shot of vodka 😂) Just 3 wires are problematic in this case.

[helgek]

Good luck with both the soldering and also the right vodka choice 😅 as mentioned the acupuncture needles are much cheaper alternative to PCBite, so in case it's not working out well this could be a backup option

[VoyteckPL]

Guys, any videos of these acupuncture needles? Never heard of this.

[helgek]

There's various examples you can find online. One is this one for instance: https://www.superhouse.tv/36-3d-printed-pcb-workstation-using-acupuncture-needles/

[VoyteckPL]

Nice. I think I will use plasticine and normal needles just for this single project.

[VoyteckPL]

@VoyteckPL because I'm not capable of soldering such things I used PCbite from Sensepeek (for me it was worth the investment because I flashed over w dozen devices). A cheaper solution are acupuncture needles. Just wanted to let you know in case you have "two left" soldering hands like me;D

Ok I decided to buy PCBite. I ordered a little bit cheaper version from TME without the base.

https://www.tme.eu/pl/details/pcbite-4005/sondy-do-oscyloskopow-i-skopometrow/sensepeek-ab/4005/?brutto=1&currency=PLN&utm_source=google&utm_medium=cpc&utm_campaign=Wyposa%C5%BCenie%20PL%20[PLA]%20CSS%20Segment_A&gad_source=1&gclid=Cj0KCQiAyoi8BhDvARIsAO_CDsBal3lJPXpoXTQwKZWP9NrY_VpHvmOXtRvh0YakWp387h8seiZvcdAaApBpEALw_wcB

What kind of base plate is it? Just a peace of stainless steel?

Another question. Which TTL particular module would you reccomend so it is powerful enough and I don't need external power supply?

[helgek]

Yes the base is just steel with magnetic properties. To connect with the pc I had very good experiences with this usb ttl uart adapter with an ftdi chip: https://amzn.eu/d/8Tulvl6

[VoyteckPL]

Thanks. I will order it then. Waiting for deliveries now, I will update when everything is here.