This is a fantastic product at a great price. Just one thing! Do NOT set the jumper to GND-VCC! This will cause a short! This is not a design error! You can use the board non-isolated the way it comes. This jumper is used to separate the opto-coupler circuit from the relay side. To fully isolate the inputs from the relays: 1) Pull the jumper and use secondary 5 volt power to the relay using GND and VCC next to JD-VCC. Do NOT use the VCC and GND pins next to the IN1 and IN2 input pins! 2) The JD-Vcc is the common for all inputs. The input side consists of the indicator LED and opto-coupler-LED and a 100 ohm resistor in series. 3) Apply Arduino 5 volt to JD-VCC and IN1 or IN2 to the Arduino outputs (LOW) and the relay will be triggered. Hope this helps! The board is missing one star for the mounting hole issue! Thanks to Eric for the schematic! You can find a schematic on amazon.

The links for the data go nowhere. The driver schematic everyone is discussing cannot be correct. The diagram would require a high voltage to activate. This board activates on low voltage. This is the beginning of a good product, but not yet.

At the same day I purchased this relay from this web site I bought the same one from eBay. I did that because the last one I ordered from eBay never arrived and I was well into my project and just needed this relay. So, to make sure I got it this time I ordered 1 from an eBay seller (2 USD with shipping) and 1 from here (5 USD + 6 USD for international shipping!). The eBay one came one week before this one! Great product, but will never order from here again.

I don’t wanna say more in details. It’s of good value with my project. Other products I ordered in your shop are great too.

I don’t wanna say more in details. It’s of good value with my project. Other products I ordered in your shop are great too.

This relay board works well with the Raspberry Pi, If I need other tools, I will come to your store again!

The relay works really good for my project. Great!

This is a good addition for my home automation project, but would be better if they elaborated on the circuits/ schematics a bit.

This is an easy interface for the RPI and nothing special is needed to interface to the 3 volt GPIO bus or a 3 volt powered I2C port expander. Having said that. the logic is backwards for a Rpi. A low (off) at the relay board's input energizes the relay. This is easily changed by cutting a trace on the board and adding two jumpers.

This board works well with the Arduino but needs more than just a schematic for the average hobbyist to be comfortable purchasing it.