SparkFun Electronics Commentsurn:uuid:214d0e4e-f1b1-d287-ce26-ac5b4c9f82492024-03-28T16:43:42-06:00SparkFun ElectronicsJohn Morris on SPX-15032 - Qwiic Quad RelayJohn Morrisurn:uuid:e899fe2b-efbe-f3da-7e91-98f458c789f42018-10-18T15:48:01-06:00<p>Seems like this is just all wrong. The datasheet for the relay used says it wants 9V minimum to engage and you are trying to run it on 5V, then you used a regulator too small to deliver enough current to drive all four at once. Worse you have the coils on the regulated supply with the data so you pretty much voided the benefit of the optoisolators since you have a direct path for spikes to get from the relays to the digital side.<p>Seems like all existing problems would vanish if you relabeled the DC jack 9-12V, reroute the relay side V+ to a point between the reverse polarity protection diode and the regulator and recalculated the dropping resistors for the indicator LEDs.</p></p>