A motion sensor and a relay should be connected with an atmega328p. I soldered my circuit on a perfboard and have 5V power and ground rails on it.
Can I use the rail for the COM port of the ULN2803a or do I need to remove the VCC, jdVCC jumper on my relay and connect a separate power supply to it? And take connect the COM port to that VCC?
It strikes me as a bit strange that I would need that many power sources for such a simple project, including the socket for the lamp that should be controlled with the relay, I'd need 3 sockets for this project.
Also, am I under the correct impression, that the use of the ULN2803a inverts my logic? Without I switched the relay ON with LOW, now HIGH provides the ON state.
And on a side note, any suggestions on how to improve my schematics are welcome. I'm just starting out and I would image that my schematic probably isn't that well to read.
Regarding the diodes:
On the product pictures on my 8CH relay these are labeled D1-D8.