I am so desperate to get this done. How do I power three 12v solenoid valves and an Arduino Uno with this 12v 5a power supply? How should I go about splitting the wires? Should I remove that barrel jack male connector at the end and if I do then how do I connect it to the Arduino....
I will be using relay modules to power it.. but my main problem is how should I go about splitting the wire, and powering the Arduino Uno with this thing while simultaneously powering 3 more relay modules?
You could cut the PSU wire part way along. Then use terminal blocks to connect the wires to the solenoids and re-use the cut-off section to power the Uno.
But an alarm bell is ringing in my head. You mention relays powering something, I guess you meant to say relays switching the power to the solenoids?
What coil voltage are these relays? Hopefully the answer is that they are 12V but if they are 5V then you will have a problem. The Uno's 5V regulator will not be able to power more than one 5V relay at a time given that it's input voltage is 12V.
I would be wiser to use MOSFET modules or DC SSRs than to use relays.
Post your proposed annotated schematic so we can see what you are planning. You can use one power supply to power everything but things have to be connected properly or you will get to purchase another Arduino making the seller happy. You also need to post a link to the technical details on the solenoid. Also let us know about how long the solenoid leads will be.
In the past few months I have had a lot of fun with this type of stuff. I have done both what sterretje and PaulRB have done to great effect. I had so much stuff lying about, like power supplies that I could butcher some and put them into a terminal block, but I also took a barrel socket out of an old piece of equipment. That barrel socket is useable with many barrel connector sizes I have. That avoids butchering power supply cables that I would rather keep intact.
Strip board and breadboard are good options too, but pay attention to the amount of current/ power that is being transmitted. Use a DMM as well to check the actual voltage from some power supplies. I found some to be terribly out of the range that was stated on the power supply information supplied with the unit. Some 12 volt DC supplies had over 15V DC!
To power 12 volt DC devices from the Arduino, use transistor switches. They are a piece of cake once you know the basic circuits (sorry if you already knew that).
Also, as a side note, if you butcher a cable from a power supply, keep the other end. You can recreate the power supply to its original state with the use of a terminal block.
