HiLetgo 2pcs DC 12V 2 Channel Relay Module with Isolated Optocoupler High and Low Level H/L Level Trigger Module Triggered by DC 12V

The Arduino Mega 2560 has a DC barrel connector that accepts 12V in. In order to get this relay to work I connect 2 wires to the VIN pin on the Arduino. VIN outputs 12volts if you have a 12v power source connected to the Arduino. The other end of these wires go to the DC+ terminal, and NO1 (or 2) when NO1 and NO2 are jumpered together. GND from the arduino goes to NC1 or NC2 which is jumpered. Then DC- goes to another GND on the arduino. I have IN1 and IN2 going to pins 7 & 8, but that's variable. The COM1 and COM2 terminals are connected to my 12v linear actuator. This works to open and close the relay. The way the LEDS light up is confusing . . . both light up when I expect only one to, but everything functions properly. NOTE that your board must put out 12v to power the relay (if you are powering from the board) like my the Arduino Mega 2560 does, but I believe (did not test, but according to documentation) pins 7&8 (in my case, or if you use other output pins) only put out 5 volts. SO . . . 5 volts is OK for setting the high or low signals, but you need 12v to power. I was confused by the seller's description which I misunderstood, and thought this couldn't work with Arduino at all. BUT BE WARNED . . . make sure your actuator is not drawing too much amperage for the board to handle. If that is the case you can power directly off of the 12v power source to the NO and NC terminals and bypass the VIN pin. However, you can still control the relay with the 5v pins to set HIGH and LOW . . . which the description led me to believe wasn't possible

The relays work as they should!You can have a choice of 2 ganged SPDT or separate SPDT or just one relay.You can also switch the relay coil to ground (recommended) or the coil to V+

These little relays are quick, reliable, and almost bullet proof! It's handy to have two sets of two relays, that are both DPDT and can be triggered by positive or negative switching! I used one to reverse polarity to a 12v servo to open a chicken coop door, and used the other one to choose whether to send the power through to the first relay or to a DPDT switch to manually control the door. I also had to use a diode to prevent the manual switch from sending power back through the normally closed contact of the first relay. Since it was reversing polarity, one of the positions would create a short. The diode did the trick. However in the process of figuring that out, I shorted these out (trial and error), but they did not damage. They are very tough built. I'm impressed!

The idea was to put two DC relays into as small a space as possible. These products worked great. No issues, just worked as advertised. Excellent product.NOTE: Be aware that each relay draws approximately 50-60ma. Trigger is approx 4ma.

I ordered the two pack the first time. One unit worked fine the other did not. The relays actuated fine but the front end electronics did not work. I ordered two more and they both came on time and worked fine. The board is small has mounting holes and terminal strips which making field wiring connections easy for both input and output. I have installed in my device and like it very much.

I bought these to use as a trailer light controller (instead of spending $30 on an actual one that did not have an option for a reverse light) for my SUV. These relay's worked perfect, and are exactly what I needed. The 12v signal needed to trigger the relay is not directly triggering the relay, there are microchips that read the signal to activate the relay resulting is VERY low signal amperage needed to trigger these relays. As for longevity, we will see...I have only made one trip with this set up so far. TBH six bucks was completely worth it if these last for a few years.

While I've not yet tried these relays, I can report that the dimensions listed are incorrect. The listing has the following:Module size : 50mm * 26mm * 18.5mm (L * W * H)Has four mounting bolts holes , hole 3.1mm, 44.5mm * 20.5mm pitchThe actual dimensions are 50mm L x 41mm W x 19.5mm H. The mounting holes pitch is approximately 44.5mm x 35.75mm. If the dimensions are important to you, know that what you'll get are not what they say. (I now have to see if I can make it fit into my design.)

It's true no schematic, but its very easy to understand. 12V coil; connect DC- to Ground and DC+ to 12V. The two switches have a common, normally closed position and normally open position and rated at 10 Amps; identified as COM1, NC1, NO1 & COM2, NC2, N02. Positive or Negative trigger is selectable by jumpers; identified as Com, High and Low. I used High trigger so I connected jumper Com to High. If you want Low trigger jumper Com to Low. IN1 and IN2 have to be at 12v in order for the relays to switch; IN1 controls relay 1 and IN2 controls relay 2. I just jumper both IN1 and IN2 to 12V Power for my application. Note: When DC+ 12v Power is on, a green led lights up. When IN1 is at 12V a Red LED lights up next to relay 1. When IN2 is at 12V a Red LED lights up next to relay 2. I actually had a wire not connected to IN1 (by mistake) and it was immediately obvious. I used 4 of these cards in my circuit so I had several wires connected and it was easily to see my error because of the lights.At this time of year (December) when my circuit is activated it looks like Christmas with Green and red LEDS.