Hey,
I've read the useful article on using solenoids with arduino on Arduino Playground - SolenoidTutorial.
This article depicts a schema in order to use a 12V DC solenoid. I'm planning to use a 220V AC solenoid valve but I didn't figured how to adapt the protection circuitry for AC power supply.
Does anyone could give me some advices of how I should mount this 220V AC solenoid ?
Thanks, cheers,
Kali
You could use a opto-triac or opto-mosfet, but it is much easier and safer to use a normal mechanical relay for this.
"opto-MOSFET" - better known as a solid-state relay, SSR - one rated for
AC mains with an inductive load would be required.
MarkT is right. SSR. Very cheap, and I use it myself.
www.ebay.nl/sch/i.html?_sop=15&_osacat=0&_from=R40&LH_PrefLoc=2&_nkw=ssr25da&_sacat=0
Those SSRs have a large RC filter (snubber circuit). Perhaps that is enough to filter voltage peaks by inductive loads, but I'm not sure.
You can be a 40A version which has also larger RC filter, and is just a cheap:
But the RC filter might conduct so much current that the solenoids could activate, or start making noise.
Ok, thanks a lot for this answers !
As I understood, the "protection circuitry" (as described in Arduino Playground - HomePage) isn't needed for AC but I must use a Solid State Relay, such as proposed in the above links)
Btw, I tried with an "opto-isolated relay" (found here : http://yourduino.com/sunshop2/index.php?l=product_detail&p=218) who works well for any lamp or electric heater (I guess they are resistances) but acts weird with solenoid valves (I guess they are inductances).
In order to make such I didn't misunderstood, I also find this thread : Interfacing a SSR relay to the arduino - #10 by system - Frequently-Asked Questions - Arduino Forum
which mentions
So although you can safely connect the SSR control pins to Arduino, you may need an RC snubber or diode to protect the SSR from the solenoid. We assume its an AC circuit you cant simply use a regular rectifier diode across the solenoid. You need a TVS diode or a MOV or something like that.
The SSR may take the abuse for a while, they are pretty rugged. Even after it punches thru your SSR may be stuck ON or OFF, but the SSR isolation should still prevent any badness from getting back into your Arduino.
Consider the failure mode of the suppression part in your design.
I didn't fully understand, but does this means some kind of TVS diode may also be needed ?
I've been using SSRs on large inductive loads (like 220VAC water pumps) for years without any additional protective circuitry (and without any problems), so I think you will be safe. However, if you have a particular SSR in mind, be sure to consult the manufacturer's data sheet for any usage cautions.
A solenoid valve is an inductance.
The snubber circuit (R + C) inside those SSRs will reduce the voltage peaks.
As far as I know there is no other transient piek protection component in it.
The relays acted weird with the solenoid valves ? I don't know why. With many inductive sparks the contacts inside the relays could be melted together or something like that.
Can you give a link to your solenoid valve ? I'm wondering how big it is 
Thanks a lot, it works like a charm now 
I didn't knew about the zero-crossover switching of SSRs, but this obvioulsy does the trick.
@Caltoa : I tried with two completely different small solenoid valves (diameter is 3/8") and the behavior is the same for both.
jremington:
I've been using SSRs on large inductive loads (like 220VAC water pumps) for years without any additional protective circuitry (and without any problems), so I think you will be safe. However, if you have a particular SSR in mind, be sure to consult the manufacturer's data sheet for any usage cautions.
Would you mins telling me which SSR's you+ use with 220VAC water pumps?
can I ask why you would use a ssr over a standard relay???
Silent, lasts more switchings (in theory), needs less drive current. They are more
sensitive to mains transients though, so I think careful attention to the snubber
used is important. For AC switches an RC snubber is usually used in place of the
diode that's used for DC. Wikipedia no doubt explains these.
how to control ac solenoid valve