Are there any problems sinking 30 ma from a UNO output pins for a 5 volt relay coil if the coil is shunted by a diode to eliminate the coils' s inductive spike.
Anyone know of a 5 volt relay card shield for the UNO that has four or more relays preferably DPDT but SPST would work if there were at least four relays. The contacts have to be for 2 amp DC minimum (@ no more than 20 volts)?
Are there shield prototyping cards that I could put four 5 volt DPDT relays on and any transistor logic that might be needed? How important is isolation of the relay coil from the UNO outputs if the relay does not exceed the 40 ma capacity of the UNO outputs and the relay coil shunt diodes are used?
I'd like to drive the relays directly from the UNO or from a shield card or as a last resort make up a relay card. Anyone got any ideas on this?