Wemos x-8266 esp-wroom-02

Other Hardware 3rd Party Boards
1

Hi there,

Anyone have worked with this type of ESP board?

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I have quite a lot of them and do not want throw them away.

My issues are;

  1. I do not know which board type I should be selecting in Arduino IDE ver 2.2.3.
    However, I used "LOLIN(WEMOS) D1 ESP-WROOM-02" so far and was able to use its GPIO pins.

  2. No matter what I do, I2C devices are not being detected. This board have dedicated marked pins for I2C, but I wonder if it is correct, or may be the board type I have selected is not correct to use I2C.

Any help would be much appciated.
Thanks.

2

I don't have any of those. The note on the diagram makes me think it's supposed to be an "ESP8266".

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Maybe it's your sketch or your wiring.

3

Hi @dinesha77.

The model-specific board definitions such as "LOLIN(WEMOS) D1 ESP-WROOM-02" are convenient because they might provide the configuration that is appropriate for a specific model of board. However, if the manufacturer of the board model you are using hasn't added such a definition to the "esp8266" boards platform, you can always use the "Generic ESP8266 Module" board definition. When you select Tools > Board > esp8266 > Generic ESP8266 Module from the Arduino IDE menus, you will find that menus for all possible configuration options of the ESP8266 microcontroller are added under the IDE's Tools menu. The purpose of this board definition is to allow the platform to support any arbitrary ESP8266-based hardware.

In the first picture you shared, the headers have only been poked through the holes on the board. You will never get a reliable electrical connection by doing that. So if you haven't soldered the connections to the I2C pins, that is likely the cause of the problem.

2 Likes
4

SDA and SCL pins might be mislabeled (inverted).

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Esp8266 commonly used default SDA is Gpio4 and SCL Gpio5.
Rest of the pinmapping looks equal to D1 mini.

5

Interesting yours being an ESP32 with the same footprint

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1 Like
6

Good eyes.
Even more interesting is the pinout, why would one bring these gpios out from esp32.. :open_mouth:

7

I think I'd try with the WemosD1R1 - use Serial and digitalWrite to ping out "D3-D8".
And definitely solder that up (or if you have minigrabbers etc. - fine).

8

cannot be either one as I tested my I2C sensor with a and UNO with the I2C scanner sketch, which is the same I use for this board

yes it is.

9

Now muting.

10

that is not my actual setup, image copied from web. But the board is same.

will test this and see.

11

I did invert, but didnt work.

12

You can use some other pins if you have doubts about those two.
Specify pins on your scanner code
Wire.begin(14, 12); //SDA pin D5, SCL pin D6

1 Like
14

Ohh good point.. how I have missed this one.. thanks. let me check that now.

15

After checking with the multimeater, located the actual pins connected to the esp-wroom-02 module.
WIRE.begin(5, 4); //SDA 5 & SCL 4

thank you all for your help.!

16

So how were those pins? Where was the error?

17

My guess would be the default Wire() pins are wrongly mapped for this specific type of board. So Wire.pins(5, 4); made it work.

18

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