Kallio DesignsTeemu Latonen
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MCP23017 Break out board IOBOB

MCP23017 BoB with DIN rail mounting and proper wire to board connectors and indicator LEDs.

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MCP23017 Break out board IOBOB

Things used in this project

Story

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Custom parts and enclosures

Enclosure drawing

Schematics

Schematic of indicator LEDs

High treshold 3/4 of supply voltage

Code

Example code for Arduino

Arduino
Example code using Adafruit MCP23017 library. Adafruit provides a variety of I2C capable controllers.
//Software License Agreement (BSD License)
//
//Copyright (c) 2012, Adafruit Industries
//All rights reserved.
//
//Redistribution and use in source and binary forms, with or without
//modification, are permitted provided that the following conditions are met:
//1. Redistributions of source code must retain the above copyright
//notice, this list of conditions and the following disclaimer.
//2. Redistributions in binary form must reproduce the above copyright
//notice, this list of conditions and the following disclaimer in the
//documentation and/or other materials provided with the distribution.
//3. Neither the name of the copyright holders nor the
//names of its contributors may be used to endorse or promote products
//derived from this software without specific prior written permission.
//
//THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
//EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
//WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
//DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
//DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
//(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
//LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
//ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
//(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
//SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include <Wire.h>
#include "Adafruit_MCP23017.h"

// Basic pin reading and pullup test for the MCP23017 I/O expander
// public domain!

// Connect pin #12 of the expander to Analog 5 (i2c clock)
// Connect pin #13 of the expander to Analog 4 (i2c data)
// Connect pins #15, 16 and 17 of the expander to ground (address selection)
// Connect pin #9 of the expander to 5V (power)
// Connect pin #10 of the expander to ground (common ground)
// Connect pin #18 through a ~10kohm resistor to 5V (reset pin, active low)

// Input #0 is on pin 21 so connect a button or switch from there to ground

Adafruit_MCP23017 mcp;
  
void setup() {  
  mcp.begin();      // use default address 0

  mcp.pinMode(0, INPUT);
  mcp.pullUp(0, HIGH);  // turn on a 100K pullup internally

  pinMode(13, OUTPUT);  // use the p13 LED as debugging
}



void loop() {
  // The LED will 'echo' the button
  digitalWrite(13, mcp.digitalRead(0));
}

Credits

Kallio Designs

Kallio Designs

5 projects • 0 followers
Teemu Latonen

Teemu Latonen

0 projects • 1 follower

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