Arduino Nano programmable timer using Tiny RTC DS1307 and 220V relays

Using Arduino General Electronics
#1

Hi everyone,

I have been trying to get into the Arduino world for a while, but I always seem to leave it for later. Anyway, I have been thinking of creating a power switch with a timer as a start. I have been looking for some information and I think it can be done, but I have one concern, I always see that the 5VCC pin is being used both by the RTC module and the relays module.

Will the arduino be able to supply that much power? Also, isn't there a risk that when the relays are operated there might be a kickback to the VCC pin? I should be using a diode in the middle between the arduino and the relays right?

The RTC module is named Tiny RTC and it uses a DS1307 controller and has a 24c32 for eeprom.
The relay module has relays branded as Songle and are rated 10A 250V

What do you think?

#2

cadash:
Will the arduino be able to supply that much power?

Depends on what powers it. If it's 12V via the jack or Vin the 1 relay is about the max. The RTC hardly draws current.

cadash:
Also, isn't there a risk that when the relays are operated there might be a kickback to the VCC pin?

No, that's why there is a diode on the relay module. (I assume you use a module.)

cadash:
I should be using a diode in the middle between the arduino and the relays right?

That would be pointless...

Bigger relays or if you switch heavier (reactive) loads can however induce noise. Then it's just a matter of adding decoupling caps close to the Arduino and the RTC.

#3