ssr relays ???

Will i need any other parts in my wireing between megga board and 3 ssr relays ? ssr are 3 -32 vdc ???

Not likely; unless the current draw of the relays is greater than what the Arduino can source you should be good. If not, then you will need to put either a TTL buffer chip in between, or a transistor. Also keep in mind how many you are planning on turning on at one time with the Arduino; if you exceed the total output of the Arduino, “bad” things could happen (not sure if you would necessarily fry anything, but you might cause spurious resets or such). Check out the spec sheet for the relay, find out how much current it draws on the signaling side, then compare to the output of a digital pin on the Arduino (as well as total available current output, vs the number of relays multiplied by their current draw). Hope this helps!

from what i can find on data sheet is that ssr are 15ma input current , and megga board is from what i find 40.0 ma dc current PER I/o pin ,
hope this is correct!

Just remember to look at the spec sheet of the device to see if you need a current limiting resistor on the input. If it needs a resistor and you drive it without one you will probably blow the device.


Martyn.

If the SSR has a voltage rated input specification (like ssr are 3 -32 vdc ) then that implies an internal current limiting resistor is inside the SSR and can be safely wired to a Arduino output pin. However there it is always good advice to get a copy of the data sheet for the SSR and review the specifications closely for piece of mind.

Lefty