Electronic – arduino – Emf interference on arduino and breadboard , using 74HC595 shift register, how to prevent it

arduinobreadboardemfnoiseshift-register

I’m using a 74HC595 chip (shift register) NPX semiconductors, connected to and arduino board. Basically the shift register switches on and off 8 leds in sequence.

Everything seem to be working, code and pin wiring to the chip are fine.

The issue is that sometimes the circuit seems to have some problems and the leds are all frozen. I've noticed that when I move the breadboard in some specific locations or simply pass the hand over some wires all the circuit starts working fine. Clearly I’ve checked all the wiring connections and from that point there is no problem. What I’m suspecting is that there is some kind of EMF noise disturbing the setup.

From what I know only high frequency application can be affected by this problem, but I’m working with just 5V and nothing is going beyond 1MHz.

What can be the possible issues? What are the topics I need to study to prevent this problem? How to prevent it?

The following are links to:
My video showing the possible noise problem
The schematics I got from fritzing.org

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I've added a 100uF capacitor, but nothing solved
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Best Answer

This is either a decoupling problem, or an unconnected wire. As the commenters have said, you'll need to add some capacitors. Fit them as physically close as possible to the 74HC595's power pins (your diagram shows it too far away). Try at least a 0.1uF ceramic capacitor as well as the 100uF electrolytic. Try as much as a 1uF ceramic.

The other possibility is an unconnected pin. CMOS parts can be affected by electric fields when there are unconnected input pins. Have you connected all the unused input pins to either Vcc or Ground? Are you sure that the breadboard wires really are making contact? Solderless breadboards are notorious for unreliable contacts.