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Monday, 22 December 2014

MyPiFi I/O Expander for Raspberry Pi assembly guide

Firstly open up the packet and sort out the parts.


First job is to solder the GPIO header on as due to it being extended you won't be able to do it later on.


Next the MCP23017 holder, make sure the semi circle indent is the right way round, ie closest to GPIO like the outline is drawn on the board.

Now we move onto the header pins 9 pins per side, I found bluetac a great way to hold the board when soldering it.


Then place the MCP23017 chip in, you will need to bend the legs slightly in to do it. I found holding it and the ends then pressing one side on its side against a flat surface lightly I was able to bend the legs inwards slightly so it would fit straight into the holder. A little bit of pressure is needed to push into the slot but be careful not to use to much as if a leg isn't in place it will break it.

Finally this is how the board should look.



The chip is controlled by the sda and scl pins on the pi.

Heres a video I made in assemblying the board (my second ever video with a new camera), its not the best quality but gives you an idea what to do. the linky is as follows:  http://youtu.be/c9pg37xRwB0

A great write up in getting this running is on the raspberry Pi spy site telling you what to do to set up a mcp23017 device, the link is http://www.raspberrypi-spy.co.uk/2013/07/how-to-use-a-mcp23017-i2c-port-expander-with-the-raspberry-pi-part-1/

Gordon has also written an excellent blog on controlling things though it too using wiringPi http://wiringpi.com/extensions/i2c-mcp23008-mcp23017/

Lastly Alex Eames from the HDMIPI kickstarter and regular Pi blogger has written this with demo scripts.  http://raspi.tv/2013/using-the-mcp23017-port-expander-with-wiringpi2-to-give-you-16-new-gpio-ports-part-3


I haven't written any demo scripts yet as there is plenty about on the Internet, but feel free to send me a link to your projects and I'll add them below.

A great place to get started with demo codes and instructions is here http://nathan.chantrell.net/20120602/raspberry-pi-io-expander-board/