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The assembled boards are $41 (way too expensive), but the bare PCBs are $3 and maybe $5 $12 in additional components. I assemble them myself.
http://www.modelrailroadcontrolsystems.com/iox32-version-2-0-32-line-i-o-expander/
Build Notes
Version 2.2 of the IOX32 does not have the slave address select pins of one of the post expanders tied to the address select headers and will always be at address 0x20. The fix was simple enough.
Microchip Port Expander
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