5v relays. Help needed.

Other Hardware General Electronics
1

Hi folks.

My "latest" project is one I am thinking of to help with all the "plug packs"/chargers I have.

For now I have a board with 4 outputs and 4 switches. If I want to charge something - usually the thing who's charger is plugged in, I simply connect it and flick the switch. It gets charged.

But I don't know if it is board-um or what, I thought it would be nice to get Mr Arduino in on the act.

So the idea came to me and I am wanting to run the whole thing on 5v to keep things simple.

However, 5v (coil) 240v (AC) rated relays are few and far between.

I have found some but am concerned with the specs:
http://www.jaycar.com.au/productView.asp?ID=SY4097
and
http://www.jaycar.com.au/productView.asp?ID=SY4088

Yeah, lots of detail on the second one huh?

As they would be switching SMALL loads, would they suffice?

Thanks in advance.

2

Define small loads?

3

Like phone chargers, camera battery chargers.
That sort of thing.

Only 1 charger / outlet.

4

l&c,
the first link quotes a load (output) current range, 0.1 - 3A.
So, they need a minimum in the on-state (100ma.)

5

2amps @ 240

480 watts max, the second relay you linked, that's enough juice to run a desktop computer....

So yeah no problem

6

I'd hope that they would be over that threshold. :slight_smile:

The 240v AC max is the thing which worries me.

Is that 240v Peak, or RMS?

7

If you plan on using a fluro or a motor you'll need a snubber circuit.

To be honest an older mechanical relay would be an option if you did.

8

lost_and_confused:
Like phone chargers, camera battery chargers.
That sort of thing.
Only 1 charger / outlet.

lost_and_confused:
I'd hope that they would be over that threshold. :slight_smile:

You can look on those items, there's probably a current listed.
220 vac,, >= 100ma -- that's a lot for a phone charger.

You should look for a 5V mechanical relay.
Those at jaycar don't have ac-rated contacts.

9

I would prefer mechanical relays.

I am "old school" but the solid state ones came into my view.

All most relays seem to be 12v (DC) and some more and also AC (coils) which would not work.

Just get the arduino's output, put it through a transistor and fly back diode and "voila"!

So that's where I am at.

I don't want to spend $20 / relay. That's a bit crazy.

At this point I am pricing things to see if it is viable.
The relays seem to be a sticking point.

10

I like ebay for that reason, except the huge delays in postage.

11

lost_and_confused:
I don't want to spend $20 / relay. That's a bit crazy.

"Crazy", that'd be it.

http://www.ebay.com.au/itm/1pc-New-1-Channel-Relay-Module-Shield-5V-For-Arduino-ARM-PIC-AVR-DSP-Electronic-/200939860395?pt=AU_B_I_Electrical_Test_Equipment&hash=item2ec8f2f1ab&_uhb=1

12

Well, I am now part of "paypal" and "evilbay".

After buying 5, I was shown a link where I could buy either an 8 or 4 way set altogether.
The 4 way would have been good with 1 single one, but that's life I guess.

Thanks.

Project moved to next stage.