Noob question: relays

Forum 2005-2010 (read only) Hardware Interfacing
#1

I am building a 6 zone AC "power strip" that has programmable on/off times to control various functions of my fish tank. Arduino will control the timing.

I need 6 SPDT (or SPST) relays that are rated at 120VAC @ 2amps (nothing in my fish tank setup uses more than 1.1 amps) that can be fired from the 5VDC digital pins on Arduino. As far as I can tell, the Arduino pins only put out 5VDC @ 40mA, correct? Are there any relays that are rated at 2 amps (for ac) and can be fired by such a low current 5VDC source?

Thanks for listening to my kindergarten question.

#2

You can't power a mechanical relay directly from an Arduino output. You will need a transistor. This is about a motor but there is a relay element to it:- http://www.thebox.myzen.co.uk/Workshop/Motors_1.html

#3

Understood. So I can control a 5VDC relay with the internal 5VDC power source on the Arduino. So then another question. If I am controlling 6 separate relays, will the 5VDC supply have enough juice to hold all six relays in the "on" position?

So, for instance: http://www.allelectronics.com/make-a-store/item/SRLY-20/3-AMP-SOLID-STATE-RELAY/-/1.html

Would Arduino have any problem running six of these at once?

#4

You should use a seperate power supply for the relays. For two reasons, the current requirements are probably to high for Arduinos powersupply and to isolate Arduino from the electrical noise from the realys.

#5