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By rjalex
JurajA wrote:D3 is io 0, D8 is io 15. this are boot config pins but the board should handle this. return the board

Thank you very much.
Would this be a defective sample or a design flaw?
I am asking to understand if I should require a substitution from the same vendor or go look elsewhere.
This is the board I ordered: ... UTF8&psc=1
User avatar
By JurajA
#85701 the io 15 (D8) must have a pull-down resistor on board. if you didn't connect some sensor or other device to the pin what pulls it high then this must work.

io 0 (D3) is connected to auto-reset circuit of the board and the upload tool should activate it at upload. again some sensor or other device wired by you to this pin can interfere.

to be sure we talk about the same board: Wemos D1 R1 is a large Arduino Uno like board with esp-12 module and large D1 label (R1 is not written on board). R2 looks the same but has a large D1 R2 label on board
Last edited by JurajA on Mon Feb 17, 2020 1:40 pm, edited 1 time in total.
User avatar
By rjalex
#85702 Yes you described well the board :)

It's exactly this one:

Now as a total newbie I am not 100% sure if I had a DHT22 wired to it or not. Meanwhile waiting for my post to be approved I have sent it back to Amazon ... will never know.

Might order another one hoping it is a good board.

Thank you a lot for your kind help. Every time you write I am learning/understanding something little new.