Relay design needed (dry set of contacts)

[Macrosill]

I need a relay that can run off the Renard 64 that will supply a dry set of contacts. I am using it to turn on my fog machine pump. I have not taken the fog machine apart yet but I think there is a relay inside there that already controls the pump from a manual switch. I have tried the hockey puck type relays and they do not work. I think it is because there is such a small load that the triac will not latch. I may be wrong in my theory but its the best I can come up with at this point. I only tried this late last night.

So I need something I can make quickly from parts that I either have or can get at Rat Shack and have it ready for Wednesday night. Nothing like waiting until the last minute!

[Jeff Millard]

I have a Strothers Dunn relay I will send you (DPDT) But you will need to use and SSR since it's 120Vac...
Jeff

[stripey_horse]

i have a fog machine

i interfaced the remote control switch to a relay using my opto+transistor interface..

http://www.christmasinshirley.com/forum/download.php?id=512
(use the +12v to turn on the relay)

i suggest if ur fog machine has a remote switch , interface into that..

edited.
and honestly , surely you are only switching on the fog for a little bit each time.. ive played a bit with mine (not much , im doing it all at the last minute as well) and a good 30 second burst gives good results once its warm..

i just got 50 x 5v relays off ebay for $28 usd. good value..

btw. im in hobart , australia. and my transistor switch costs around $1.65 per channel without the relay..

[Macrosill]

It has a remote control switch. I bought a cord with a mating plug to go into the fog machine remote port and need a relay to close the 2 conductors that turns on the fog pump, in place of the remote switch.

[stripey_horse]

im doing the same thing.. feel free to msn me if u need any help. stripey_horse@hotmail.com

im using my transistor switch , to switch on a relay.

my fog machine remote has a switch.. so im just going to bypass the switch with the relay.. and that will mean i wont have to switch high currents , only low currents..

i figure since its isolated from the 595 its totally safe

btw. im going to use piping on the lawn to distribute a ground fog.. just gotta get the timing right..

[DynamoBen]

Are you sure you need a dry contact? I have a similar fog machine and after some poking around I discovered that the relay (inside) was acutally fired with 12V through the switch in the remote.

I ended up using a transitor, not a relay to control the fogger. The transistor option will only work if the common from the fogger is tied to the common on your controller.

If you must go the relay route, rat shack has a pretty big selection considering...

Don't forget about duty cycle you don't want to fry the relay. The 275-232 should do the job if you are running at 5V, 275-233 for 12V. I've used both in the past and they have worked well.