2021 Jun 25, 01:13 PM
(This post was last modified: 2021 Jun 25, 01:24 PM by astrogerard.)
The 10K in the Wiki is connected to pin 13 of the hc595.
The capacitor and preferably the 100 Ohm resistor is in pin 12 of the hc595. The 100 Ohm resistor should go between the brown wire and the Pi. But as close to the breadboard as possible. The capacitor should go behind the resistor on pin12 of the hc595 and gnd.
Yes I know the wiki shows a connection between the two rails. That is only valid if you have one psu. When using galvanic isolation (by far the best solution) the should not be any connection between the rails otherwise the whole concept of isolation will fail. (and most likely kill your Pi on the next lightning storm)
A power down button is fairly easy to implement but do you/we really want that? A few month per year I'm a 2 day drive away from home so if I by accident push the wrong button my plants will die :-)
A multimeter is essential to have but you can't see noise or spikes. To identify a problem I sometimes use a battery or powerbank to supply 12v or 5v just to eliminate the mains psu and see if that solves the problem. It is not a permanent solution but can push your thinking in the right direction.
@Dan, do you know if there in de code some initialisation of the Pi's internal pull-up or pull-down resistors?
--Gerard
The capacitor and preferably the 100 Ohm resistor is in pin 12 of the hc595. The 100 Ohm resistor should go between the brown wire and the Pi. But as close to the breadboard as possible. The capacitor should go behind the resistor on pin12 of the hc595 and gnd.
Yes I know the wiki shows a connection between the two rails. That is only valid if you have one psu. When using galvanic isolation (by far the best solution) the should not be any connection between the rails otherwise the whole concept of isolation will fail. (and most likely kill your Pi on the next lightning storm)
A power down button is fairly easy to implement but do you/we really want that? A few month per year I'm a 2 day drive away from home so if I by accident push the wrong button my plants will die :-)
A multimeter is essential to have but you can't see noise or spikes. To identify a problem I sometimes use a battery or powerbank to supply 12v or 5v just to eliminate the mains psu and see if that solves the problem. It is not a permanent solution but can push your thinking in the right direction.
@Dan, do you know if there in de code some initialisation of the Pi's internal pull-up or pull-down resistors?
--Gerard