2021 Jun 22, 08:45 PM
Congrats with this important step!
No, there is no need to connect GND next to N1. The circuit "starts" on the +5V, then via a resistor, the optocoupler led and the red external led it connects to pin N1..8. Then the shift register IC pulls the pin (N1..8) low which essentially is GND. So the led will turn on.
The secondary power supply can now be connected to GND and JDC-VCC. Don't forget to remove the jumper!
Once connected the relays should make the sound you are waiting for a long time :-)
--Gerard
No, there is no need to connect GND next to N1. The circuit "starts" on the +5V, then via a resistor, the optocoupler led and the red external led it connects to pin N1..8. Then the shift register IC pulls the pin (N1..8) low which essentially is GND. So the led will turn on.
The secondary power supply can now be connected to GND and JDC-VCC. Don't forget to remove the jumper!
Once connected the relays should make the sound you are waiting for a long time :-)
--Gerard