The product funktionniert and can be used very easily, once it has been found that the circuit is low active. Unfortunately, it is not immediately recognizable by the lack of wiring diagram. The circuit has a lot of sophistication. such as the possible separation of the supply voltage of the signal circuit and the power supply for switching the relays. (5V). This is important in the use of a microcontroller such as the Arduino Due operating at 3.3V. A possible enhancement would be the use of a demultiplexer at the input, to reduce the number of control lines.
