Firstly, hi everyone, I'm new on here and new to Arduino so Hello World
I'm after a bit of advice if anyone would be willing to help me out.
I'd like to connect this relay board :
to my shiny new mega but I'd like to power the reay board from an external psu rather than drawing too much power from the Arduino pins.
Please could you tell me, if I bought a 5v 200ma psu, would I connect +5 from the psu to vcc on the relay board and psu ground to gnd on the relay board and then psu gnd to gnd on the Arduino ?
Like this :
(+) ---------->To Relay Board VCC
(-) ----------|--->To Relay Board GND
|--->To Arduino GND
If I do this then will it mean that the 15-20ma each relay requires to actuate will be drawn from the external psu?
I know each pin can supply up to 40ma and so I should be fine without an external psu but the problem is that I also need to connect 10-15 leds to the digital out pins and I have a rtc on the pwm and also a lcd, a few temp sensors and an sd card so it may be possible that at any one time the drain could exceed the total rating.
Thankyou in advance, I'm currently rubbish at electronics but I'm trying so your help is hugely appreciated.