The 8x relay board, which can be controlled by Linux and can be used for automation. The following components are located on the board and are indicated in the photo given above by the following numbers:
- If 8 relays are not sufficient the board allows concatenation of several boards in daisy chain mode. The software supports the controlling of the relays on the concatenated boards. The interface outlined by (1) is used for the connection between the boards. If several boards are used the jumper JP1 mus be activated.
- The board is connected to the PC by serial cable. The serial plug has to be connected to the socket indicated by (2).
- Furthermore it is possible to connect the board via USB. In this case the socket (3) will be used.
- For USB mode an additional adapter with product number 197257 is needed. This adapter is available at Conrad for approximately 15 Euro. Only by adding this USB to RS232 adapter the relay board can be connected to the USB port of the PC.
- The connections indicated by (5) are used for the power supply of the relay board. The board needs a supply between 12V/DC to 24V/DC. Hence most standard transformers are sufficient.
- The 8 relays that can be controlled are indicated by (6).
Each relay is equipped with an additinal LED which visualizes the state of the relay. An additional LED is available at one side of the board and indicates the status of the power supply.
Controlling <24V consumers
The relays can be used for up to 7A/24 V/DC, e.g. it is therefore possible to connect the power button of an ATX-PC to one of the relays (i.e. the corresponding pins on the mainboard). In this way the pressing of the power button can be controlled by the relay board. This can be used for systems that do not support WOL.
Further details to possible scenarios where the relay board can be used can be found in the article (in german) Verbraucher per Netzwerk ein- und ausschalten – Teil 1 / Hardware und Verbraucher per Netzwerk ein- und ausschalten – Teil 2 / Software.