Hello, I’m making a simple climate control for my aquarium and currently I’m puzzled with selecting a correct power supply.
Schema description: Arduino UNO with a bunch of sensors connected + RTC + 4 relay shield + LCD2004.
So I need to power Arduino, a fan (using TIP120 to control its speed) and presumably I need a separate power for relay shield.
I’d like to have only 1 power supply for this whole setup. Given that, it looks like I won’t be able to completely isolate the relay shield, since it’s going to be using the same power supply as Arduino.
Arduino needs 9v, relay 5v and fan 9-12v (and I’m struggling to determine the current each of these units need). So I was thinking either get some power supply like this: 60W-Dual-output-5V-12V-Switching-power-supply which seems to be a bit of an overkill or get a decent 9v 2-3a wall wart and use L7805 with capacitors to power the relay.
Any cons and pros of either of approaches? Currently I tend towards L7805, since it’s cheaper, probably gonna be physically smaller and it won’t look like I’m buying a power plant to power a single lamp. But then again, is a complete relay isolation that important?
Thanks in advance for any advice.