I'm doing an Arduino tutorial using a 74hc595 shift register to drive 8 LEDs. I have followed the wiring diagram in the tutorial, and I think I have it right, but for some reason the LEDs only work as they are supposed to when I put my finger on the 74hc595. I was wondering if this indicates a problem with the chip or if I have the wiring incorrect somehow?
Loose connection? Bad breadboard?
That's what I'm wondering. If it's just a faulty component or I've done something incorrect.
Put a 0.1uF ceramic capacitor between pin16 of the 595 and ground.
You may also have some loose connections, check them.
Remove the 595 and put it back in.
Hi, I have had similar issues with my breadboards and wires. Try moving the shift register to another spot and hooking up all the wires again, sometimes the breadboards do not fully connect to the pins of the shift register or the wires. I have also had the clock, latch and data assignments wrong, which would also display a similar problem to what you are having.
If work of project changes because you press the chip with your finger, there can be nothing else but bad contact.
Check for unconnected pins or open wires.
De-coupling tutorial
I experienced similar issue and de-coupling did not help.
However I did not use the SRCLK and RCLK properly, I only connected the SRCLK.
It was as if my finger provided a connection between the two thus giving clock signal to RCLK.
Fixing this solved the issue for me by providing a RCLK signal that's slightly delayed from the SRCLK.
Hope this helps someone.
P.S.
Not a similar issue, the exact same issue.
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