6Pack 2 Channel DC 5V Relay Module with Optocoupler Relay Board for Arduino Raspberry Pi MEGA2560

The 4 channel relays work as advertised. While the pictures indicate that the module can be driven directly from an Arduino board, make sure it can source that much current on the 5V input.A typical Arduino Mega can provide a maximum of about 1W on it's internal 5V supply, which translates to about 200mA. But when all 4 relays are turned on, the 5V draw is about 280mA.Recommend that an inexpensive (external) DC to DC supply is used to provide the 5V to the relays instead of the Arduino board as was shown. Note that the relay board even has a pin which can be used to provide that external power once the jumper is removed.Gave it 5 stars though because it works just fine. Good value for the cost.

Stays cool under 24v 6 amp power draws. I use this to raise and lower a chain at the end of my driveway using an actuator and this PCB allows me to Extend and Retract the actuator, ie essentially reversing the circuit with an arduino uno and some code. I key off the 24v power supply in my Driveway Gate Controller further down the driveway. Gate opens, chain drops and vice-versa. Since this is in the Virgin Islands, heat tolerance is paramount.

Great relay modules using industry standard components. These are what SainSmart used to carry but they no longer list dual relay modules. Given the price for this, I think I understand why. I had actually looked there first, noted they don't sell them any more, then hit AMZ and found them here.I have modules from both sources and these are exactly the same - same pcbs, same components, same placement, etc. Good stuff!

First 2 I opened didn't work? The 3rd one worked fine then suddenly stopped outputting power? One half of the double would work the other won't? This continued working then not. I gave up before opening the other 3, ended up buying a different relay. The single relays worked better for me then the doubles?

No issues.

Great value for a quality product. Just note that there is no separate ground pin for JD-VCC so if you are using an a separate power supply for the high power side of the realy then you have to use the common ground pin on the low power side.

Can't actually set it to active high, can only be controlled active low. Works fine otherwise.

Used these to set up some sequential triggers for consumer pyrotechnics. Works well!