ESP8266 NodeMCU v3 + dht22 + hx711, problem

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hunterwc

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Hi.
I am making a small project with NodeMCU v3 module, and i have problem with power supply. The device will be power by four AAA bateries, which give 6V. And now, how i should connect hx711 module with esp8266, because NodeMCU v3 has only 3,3V pin, and i need 5V to power load cell by hx711. Can anyone help me? Maybe i should use 5V and 0,1A regulator?
 

Hi,

If one device needs 5V, then use a 5V voltage regulator.
If another device needs 3.3V, then use a 3V3 regulator.

But usually you have signal lines when those two devices communicate with each other. Then you need level translators.

Klaus
 
So I can't connect it like this?


I need level translator?
 

hunterwc said:
So I can't connect it like this?
View attachment 134473

I need level translator?
Click to expand...
Yes on all the lines going between the ESP8266 and the HX711.

This is mentioned on the summary page for the ESP8266 device on sparkfun.
Note: The ESP8266 Module is not capable of 5-3V logic shifting and will require an external Logic Level Converter. Please do not power it directly from your 5V dev board.
Click to expand...

- - - Updated - - -

though according to the HX711 datasheet it can be powered from a 2.7-5.5V supply, so theoretically you could power both off of 3.3V if you wanted and avoid any level translators.

- - - Updated - - -

It does look like the ESP8266 device itself can have a digital supply of 1.8-3.3V, so if it's on a module I'd first make sure they are not using a 1.8V supply on the digital lines. You should check the device or module datasheet to verify.
 
OK, thanks for explanation. I need 5V because U\unfortunately load cell has a 5-12 operating voltage.
 

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