One Raspberry Pi 3 B & Four IO PI expanders
2182 Views - Created 24/06/2017
If you are using mostly inputs and the outputs will not be drawing much power then you can probably get away with powering the IO Pi Plus boards directly through the Raspberry Pi GPIO connector. Each of the MCP23017 IO chips on the board can supply up to 125mA to the IO bus so with four boards mounted to the Raspberry Pi the most power it could draw if you put the maximum load on every chip is 1A. As most of your signals are inputs it will not draw anywhere near that amount so the GPIO connector should be able to supply enough current.
The IO Pi Plus boards stack on top of each other. I would recommend using our mounting kits to hold the boards secure on top of the Raspberry Pi. As you are planning on stacking four boards it may be worth using right-angle IDC sockets on the boards with ribbon cables going to your other devices. We designed the IO Pi Plus to work with the right angle or straight IDC sockets but you can only use right angle sockets if you want to stack the boards as there isn't enough clearance for the straight socket and ribbon cable to sit in between the boards.
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