Help with CNC 3018 from Banggood

[Kitwn]

I've just had a closer look at the picture and the blue board at the bottom is an Arduino Nano microcontroller board (or clone thereof). If the inputs from the switches are connected directly to the Nano without any other external circuitry then the inputs will be high impedance, floating unless they are specified as ' PULL-UP' in the software configuration.

[Doddy]

I've just had a closer look at the picture and the blue board at the bottom is an Arduino Nano microcontroller board (or clone thereof). If the inputs from the switches are connected directly to the Nano without any other external circuitry then the inputs will be high impedance, floating unless they are specified as ' PULL-UP' in the software configuration.

Completely agreed.

My gut feeling is the the inputs will be (for god sakes!) configured with internal pull-up. But that is insufficient in this type of environment (it's barely good enough for bench-level development). The problem is not the ATMEGA328 chip, nor the Nano, but the implementation of the Nano onto the Developower board where the use-case should have been well understood by the designer. That board should have had pull-ups/downs on each input to the Nano. It's a poor design, destined to fail and cause frustration wherever it is used.