aweber1nj
Posts: 13
Joined: Fri May 24, 2013 8:11 pm

Sainsmart SSR Wiring?

Tue Jun 25, 2013 3:38 pm

I actually have a Sainsmart 5v relay as discussed in a few other threads, but want to try the solid state relay to see if it's less complex to connect (I realize the cost is significantly more, it's for AC only, etc. -- just going for simplicity here).

This is the one I bought: http://www.sainsmart.com/8-channel-5v-s ... duino.html

From what I read, the 3.3v GPIO output should be able to switch each relay without having to resort to manipulating 5v (though I'm not adverse to directly connecting a separate 5v power-supply just to the board).

My main question is: Is this one simple to the point that I could connect a GPIO directly to each input of the relay? Would I need something else in the circuit (outside of the relay's circuitry, of course)? Do I need a resistor for safety or something on this output?

Thanks,
AJ

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Richard-TX
Posts: 1549
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Location: North Texas

Re: Sainsmart SSR Wiring?

Tue Jun 25, 2013 7:46 pm

I am not sure why Sainsmart does what it does, but I am driving solid state relays directly from the GPIO on the Rpi. SSRs require 3-30VDC to trigger so the Rpi is a natural.
Richard
Doing Unix since 1985.
The 9-25-2013 image of Wheezy can be found at:
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derickrd
Posts: 4
Joined: Wed Jul 04, 2012 12:45 am

Re: Sainsmart SSR Wiring?

Tue Aug 27, 2013 3:27 pm

Richard-TX wrote:I am not sure why Sainsmart does what it does, but I am driving solid state relays directly from the GPIO on the Rpi. SSRs require 3-30VDC to trigger so the Rpi is a natural.
How do you connect the SSR to the GPIO? I am using pull down resistors but it does not seems to work. Did you connect directly to the GPIO?

Thanks for your help!

derickrd

BudBennett
Posts: 89
Joined: Fri May 17, 2013 2:45 pm
Location: Westcliffe, Colorado, USA

Re: Sainsmart SSR Wiring?

Tue Aug 27, 2013 10:34 pm

You should be able to drive the SSR input directly with the GPIO output. It will turn on at about 1.5V if I am interpreting the schematic correctly. Here's a schematic of a single channel:
OneRelayChannel.png
OneRelayChannel.png (26.59 KiB) Viewed 5272 times

jamesboag
Posts: 4
Joined: Wed Nov 27, 2013 11:02 am

Re: Sainsmart SSR Wiring?

Thu Jun 19, 2014 12:45 pm

Hi Guys, I bought one of these boards to Raspberry Pi-ify up my aquarium, I have quite a few 12v Lights and was hoping to use this to turn them on and off via webiopi. I can get the led on the Sainsmart board to turn on and off but when i have a 12v load on the live side they turn on but not off, Any Clues !

derickrd
Posts: 4
Joined: Wed Jul 04, 2012 12:45 am

Re: Sainsmart SSR Wiring?

Thu Jun 19, 2014 12:52 pm

Hi James, I have found out that the Sainsmart SSR relay board needs an AC signal in the live side as you called it. This means that the signal have to pass thru 0 volts (zero crossing function) in order to deactivate the relay. I guess you need a mechanical relay board and since you need a 3.3 V signal to get it on, you should use an external power supply and a transistor to boost the signal and current.

Hope this helps.

Derick DeLeon

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