Uno + NodeMCU 12E wiring

Hello,

i am following this picture for serial connection btwn Arduino UNO and NodeMCU 12E

i am using this for current measuring and i get different data on UNO and on Node…i dont know what can be the problem?

is this wiring ok?
how to check if i made good connection or if the resistors are good?

i am asking this, because when i measured resistors 1K and 2K i god the same value, but when i measured voltage which must be 3.3v i god 2.8…but resistance were ok

then i changed resistors and put 1K with 470 Ohm and got 3.3V on output

is this ok?

To make it easier, use an online calculator.

http://www.ohmslawcalculator.com/voltage-divider-calculator

But for understanding, when using high resistance values, you must take into account the consumption of the input itself, which must act as if it were a resistor (in DC).

Let's say the input consumes 1A and the applied voltage was 10V, so the equivalent resistance would be 10 Ohms.

Therefore, when using a voltage divider, it may be necessary to consider the characteristics of the load, which in this case is an input.

Note that the digital inputs have an acceptable voltage range, both for high logic state and low logic state. This can be found in the datasheet of the microcontroller.

One question: why are you using Arduino Uno together with ESP12 if you could only use ESP12?

rtek1000:
One question: why are you using Arduino UNO together with ESP12 if you could only use ESP12?

Now that is a seriously good question! :sunglasses: