I am wanting to have multiple 5v power sources. To power a Nano, Uno, and a relay control board (in which I want a separate isolated power supply). These items will only be contained in one project box.
What would be a fast, neat way to accomplish this.
The current draw would be minimal
Just a few LED's on the Uno
A small 128x64 monochrome Oled on the Nano.
The relay board (4 relays) will be to control 110v devices, so they would only need enough current for the relays to be activated.
I am thinking about running a 110v chord to the project box and just tapping it into the cable of a multiple output USB charger.
I however am hoping there is a way I can keep the 110v out of the project box and figure out another way to accomplish this.
Yes you are right, the 110 would still be on the relay screws, not sure what I was thinking.
But as far as the USB, is it ok to just wire it to multiple devices. As for the relay, if I were to use the same usb cable, how could I isolate it to use it as the power for the relays. I have been told it is important to have an isolated power supply for the relays so that the relay power doesn't travel back to the arduino.
Sorry for my naivety, I am learning lots, but still struggling on things that may seem simple to seasoned people.
I have a few projects that switch AC. I use two boxes glued together with a hole in between them. In one box is all the AC components as well as the relay. I bring, into the AC box, wires for power and signal. I seal the hole between the 2 boxes with hot glue. The AC components are in a box that I have to remove screws to access. The MCU and components go in the other box, which would have a easy to snap on/off top.
No, I pass the power, gnd, signal wire, and 2 oppsie wires through the hole before sealing the hole. The wires from the MCU to the relay are mated to a connector.
Sounds interesting, what you making? Just trying to remember but the NEC requires a barrier between low voltage and high voltage devices (110 is considered high in this case). I went though this about 20 years ago with my home automation systems and the local inspector (always a great help). In my case I had it under a permit and if the inspector recommended it it will be passed. As mentioned above back to back boxes meets this requirement nicely. We are also required to use wiring with an insulation rating capable of the high side voltage, in this case 300V. The relay is considered an isolation device as the 110 does not connect to the coil. This allows the drivers to be on the low voltage side of the barrier and wires passing to the relay, On some of my projects I put a duplex in the cover and use one outlet to power the charger.
mauiman808:
I am wanting to have multiple 5v power sources. To power a Nano, Uno, and a relay control board (in which I want a separate isolated power supply). These items will only be contained in one project box.
Can you not power the Nano and Uno from one supply - I understand wanting separate power for the
relays (they are opto-isolated I presume).
So why not two supplies, one for the relay module, the other for the rest?
