How to connect 3 HX711 to the same Arduino (Nodemcu ESP8266)

Using Arduino Project Guidance
#1

Hi guys, this is my first question. I am really new at this (started this week).

I've tried to find an answer to my question but no success. Sorry if this is also the wrong place to ask.

I am building a project. This project consists of building 3 scales. Each scale will have 4 load cells connected to a load combinator and then the load combinator connects to HX711.

The question is:

Can I connect 3 HX711 to the same Arduino? (the board that I have is Nodemcu ESP8266).

Thank you so much for potential assistance.

#2

Yes, you can.

#3

Thanks for replying.

Is there any special requirement that I need to be aware of? Like having enough power to be supplied for everything.

I am planning to use a USB Hub with 5v 2A. Is this enough to supply power to 12 load cells, 3 load combinator, 3 HX711 and the Arduino itself?

Thank you

#4

Loadcells virtually don't use any noticable power. Bu you'll need to use some bitbanging for communication.

#5

Thank you.

Not sure if I am can keep asking questions, but would you mind explaining what is bitbanging?

Is it hard to implement? Is this via software or hardware? Thanks

#6

You won't need to do any bit-banging. Use one of the available Arduino libraries for HX711 and all the bit-banging is taken care of for you.

Bit-banging is the term for emulating some digital interface in software instead of using some specialised hardware built into the Arduino's MCU chip. The built-in hardware implements standard interfaces like SPI, I2C and Serial. But the HX711 uses a non-standard interface, so there is no choice except bit-banging.

Each HX711 will need 2 pins, so 6 in total. This will be most of the available pins on an ESP8266. If pins is a problem, it may be possible to share the same pin for "CLOCK" for all 3 HX711s, I'm not certain.

#7

Thank you so much for your help! I really appreciate your assistance.

#8