Relay #103020005 & MKR WiFi 1010

I’ve used two of these with a MKR WiFi 1010 mounted in the MKR Grove Carrier and neither one will trigger. The relay LED flashes and then slowly lights dimly. The relay terminals are not connected. The relay itself is marked HLS8L-DC3V-S-C but it will not activate from the 3.3V digital output from the MKR board.

I’m not familar with the devices you mention, but it very much sounds to me that the “MKR WiFi 1010” cannot supply the current the relay needs. From the part number I’m guessing it’s a 3.0V relay which probably does need quite a high current. I suggest you check what current it needs and what current you have available from the digital output. If you have a 3.3V supply line which can supply the necessary current you could use a transistor to drive the relay - e.g. resistor from the output into the base of the NPN transistor (resistor big enough to limit the current, small enough to turn the transistor hard on), the emitter to ground and the relay connected between the collector and the 3.3V supply. Don’t forget a bypass diode across the relay!

Hope this helps…

I found I could use the Grove connector cable terminated with 4 male pins on the other end. Red to 5V Arduino supply, black to GND, and green to my digital output. The relay triggers fine when the digital pin goes HIGH.