SHT31-DIS not working with ESP8266 / Wemos D1 mini

ESPHome
1

Hi all,

I’m playing around with different environmental sensors connected to an ESP8266 (Wemos D1 mini at present) to make a bunch of environmental sensors for around the house. Everything works except the SHT31-DIS units (https://www.aliexpress.com/item/1005007217277834.html?sourceType=1&spm=a2g0o.wish-manage-home.0.0) hang my module.

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Plenty of success connecting a couple of DS18B20’s, BMP280, and SHT31 sensors with an OLED display (so my YAML is fine), but the moment I connect the SHT31-DIS and power up the D1 mini it hangs on boot.

This module supports Vcc in the range 2.4 to 5.5VDC, so I’ve tried both 3.3V and 5V without success. I’ve disconnected all other sensors in case it’s a current draw issue, but that didn’t help. I’d expect electrically it would be close to the SHT31 which works fine off 5VDC.

Maybe the wiring diagrams (same on all sites I’ve checked) are incorrect? Have tried tracing wiring but that’s a challenge!

Has anyone had any luck with these?

2

Anything useful in the logs?

3

Connected to 3.3V, GND, Gpio4 and 5?
An nothing else wired to Esp?
Post your yaml.

Ps. Don’t power sensors at 5V, you will damage your Esp.

4

Nope - device fails to connect on powering up with SHT31-DIS connected,

5

Point taken on sensor powering. I power the D1 mini via USB, then power sensors using it’s 5V or 3.3V pins. Both work for the other I2C devices connected.

The SHT31-DIS is connected to 3.3V, GND, and I2C on GPIO4 & GPIO5. I have a regular SHT31 I can swap with - it works, uses the same 0x44 I2C address as the -DIS version. I have connected an SSD1306 OLED display, a BMP280, and SHT31 on I2C plus DS18B20 on D6. Just testing at present - don’t need that many temperature/humidity sensors!

Swapping the working SHT31 and SHT31-DIS devices and checking again today, I noticed the -DIS sensor gets immediately warm on powering up, even with only Vcc and GND connected. Strongly suspecting the pinouts are marked incorrectly, will get the jeweller’s loupe out and trace the tracks later today.

6

I was expecting that. If esp doesn’t boot and no strapping pins are used, there’s short circuit.

7

I think all module pinouts published on AliExpress (every module supplier I could find has the same pinouts shown) are wrong. Using the same image from above as module pin references, I got it working with:

  1. Not required
  2. SDA
  3. SCL / SCK
  4. Not required
  5. GND
  6. Vcc (3.3VDC)

So both data AND both power connections are swapped when compared to website references! Or perhaps it’s a Southern hemisphere inversion thing… :joy:

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