as long as the switching coil needs no more than 200mW @ 5V?
Quoteas long as the switching coil needs no more than 200mW @ 5V?No the arduino pin can only supply safely about 35mA, so no more than that.
There are relays with diodes included... I used one one time and forgot about the diode... You can guess the rest, made 300 of those boards and I had to "Eat" them. The relays are made by several outfits including Omron. Yes you can power a relay directly from a processor but it is better not to... for some obvious reasons and some not so obvious... My view is that it isn't a grreat idea and does have some drawbacks but as always IF it works properly and doesn't impact anything else going on then DO IT. Just be aware that some times there are.. Better methods. (engineers make mistakes too, just hundreds of the same one... at a time)Doc
made 300 of those boards and I had to "Eat" them.
...an example ishttp://www.digikey.com/product-detail/en/TSC-105L3H,000/PB1017-ND/1095338