Details- Adding Relay Boards

Ribbon Cable Connections:

Now, for connecting the relay board hardware to the IO Pi Plus board. As for cables and connectors, I bought 20-wire ribbon cable locally. From Amazon. I bought “Antrader 20 Sets 2.54mm Pitch Connector FC-20 Pin Straight IDC Box Headers Connector Box Headers Female Connector”, 20 of ‘em for $7.00+, pictured above. The thinking, here, is that I have to mate up a 20-wire ribbon cable with two 10-pin relay boards, so I can use two 20-socket box headers separated along the ribbon cable, plug one on the relay board pins with the upper row , and plug the other relay board’s pins with the other header’s lower row. …make sense? …more about that later.

Allow plenty of room between connectors along the ribbon cable for being able to bridge the gap between cards. Just make sure you plug the upper row of one connector on one board and the lower row of the other connector on the other board. After testing, you can block the lower row of sockets on one and the upper on the other with a hot glue gun, but don’t do it until you’ve tested everything and make sure that the cables work. They might not work on the first try if you’re fumble-fingered like me.

For the relay boards, I bought four 8-SPDT relay boards from Robot Shop Inc, “8 Channel 5V Relay Shield Module,” code RB-Suf-19 manufactured by SunFounder, $48 total, and two DPDT 4-relay boards, “ELECTRONICS-SALON Four DPDT Signal Relay Module Board, 5V version” from Amazon for $20.00. The 8-relay boards accept 10-pin sockets, as described above. The DPDT boards accept only bare wire for screw-terminal connections, so you have to separate and strip out the ends of that ribbon cable. I suppose I could have done the same with the 8-relay boards and soldered female sockets on the ends, but that’s a lot of work. At the planning stage, I wanted a clean installation. As a fallback position, I could have gone with soldering female individual sockets, or else wire-wrapped and soldered directly to the pins. Testing will tell! As you will see, fortunately mine worked fine.

8-relay SPDT Board. 4-relay DPDT Board