Help with Arduino Mega With Relay8 Boards

1

Hi Guys, im having trouble with getting my Arduino to actually communicate over the i2c bus to toggle relay outputs.

This is the code i currently have,

Relay Controller MQTT Code

#include <SPI.h>
#include “Ethernet.h”
#include “Wire.h”
#include <PubSubClient.h>
#include <stdlib.h>

#define SHIELD_1_I2C_ADDRESS 0x20 // 0x20 is the address with all jumpers removed
#define SHIELD_2_I2C_ADDRESS 0x21 // 0x21 is the address with a jumper on position A0

#define MAC_I2C_ADDRESS 0x50 // Microchip 24AA125E48 I2C ROM address

/* If channelInterlocks is set to true, the channels are grouped into

  • pairs starting at 1 (ie: channels 1 & 2, 3 & 4, etc) and only one
  • channel in each pair can be on at any time. For example, if channel
  • 1 is on and 2 is set to on, channel 1 will be turned off first and
  • vice versa. This is to allow control of dual-active devices such as
  • electric curtain motors which must only be driven in one direction
  • at a time. */
    const byte channelInterlocks = false;

/* CHANGE THIS TO YOUR OWN UNIQUE VALUE. The MAC number should be

  • different from any other devices on your network or you’ll have
  • problems receiving packets. Can be replaced automatically below
  • using a MAC address ROM. */
    static uint8_t mac[] = { 0xDE, 0xA7, 0x0E, 0xEF, 0xFE, 0xED };

/* CHANGE THIS TO MATCH YOUR HOST NETWORK. Most home networks are in

  • the 192.168.0.XXX or 192.168.1.XXX subrange. Pick an address
  • that’s not in use and isn’t going to be automatically allocated by
  • DHCP from your router. Can be replaced automatically using DHCP. */
    static uint8_t ip[] = { 192, 168, 1, 182 };

static uint8_t serverIP[] = { 192, 168, 1, 108 };

char* outputTopic="/output";
char topic[37];
char message[22];

byte shield1BankA = 0; // Current status of all outputs on first shield, one bit per output
byte shield2BankA = 0; // Current status of all outputs on second shield, one bit per output
EthernetClient ethClient;
PubSubClient client(serverIP, 1883, ethClient);

// New message receive
void callback(char* topic, byte* payload, unsigned int length) {
String strPayload= String((char*)payload).substring(0,length);

Serial.print(“Receive message”);
Serial.println(strPayload);

// topic will be something like /relay/power/1/01

char channel[]=" ";
channel[0]= *(topic+13);
channel[1]= *(topic+14);

unsigned short int relay = atoi(channel);

if (strPayload.equals(“on”))
{
setLatchChannelOn( relay );
publishState(atoi(channel),1,outputTopic);
Serial.print("Turning on ");
Serial.println(channel);
}

  if (strPayload.equals("off"))

  {
    setLatchChannelOff( relay );
    publishState(atoi(channel),0,outputTopic);
            Serial.print("Turning off ");
             Serial.println(channel);
  }

}

void setup()
{
Wire.begin(); // Wake up I2C bus
Serial.begin( 38400 );
Serial.println(“Strting MQTT Relay 8 board”);

Serial.print("Getting MAC address from ROM: ");
// mac[0] = readRegister(0xFA);
// mac[1] = readRegister(0xFB);
// mac[2] = readRegister(0xFC);
// mac[3] = readRegister(0xFD);
// mac[4] = readRegister(0xFE);
// mac[5] = readRegister(0xFF);
char tmpBuf[17];
sprintf(tmpBuf, “%02X:%02X:%02X:%02X:%02X:%02X”, mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
Serial.println(tmpBuf);

// setup the Ethernet library to talk to the Wiznet board
Ethernet.begin(mac, ip); // Use static address defined above
//Ethernet.begin(mac); // Use DHCP

// Print IP address:
Serial.print(“My IP: “);
for (byte thisByte = 0; thisByte < 4; thisByte++) {
// print the value of each byte of the IP address:
Serial.print(Ethernet.localIP()[thisByte], DEC);
if( thisByte < 3 )
{
Serial.print(”.”);
}
}

/* Set up the Relay8 shields */
initialiseShield(SHIELD_1_I2C_ADDRESS);
sendRawValueToLatch1(0); // If we don’t do this, channel 6 turns on! I don’t know why

initialiseShield(SHIELD_2_I2C_ADDRESS);
sendRawValueToLatch2(0); // If we don’t do this, channel 6 turns on! I don’t know why

Serial.println(“Ready.”);
}

void connect() {
if (client.connect(“arduinoClient”, “openhabian”, “bedrock”)) {
Serial.println(“Connected”);
client.subscribe("/relay/power/1/#");
}
}

void loop()
{
if (!client.connected()) {
connect();
}

client.loop();
}

void publishState(int channel,int state,char* theTopic) {
sprintf(topic,theTopic,channel);
sprintf(message,"{channel:%1d,state:%1d}",channel,state);
client.publish(topic,message);
}

void initialiseShield(int shieldAddress)
{
// Set addressing style
Wire.beginTransmission(shieldAddress);
Wire.write(0x12);
Wire.write(0x20); // use table 1.4 addressing
Wire.endTransmission();

// Set I/O bank A to outputs
Wire.beginTransmission(shieldAddress);
Wire.write(0x00); // IODIRA register
Wire.write(0x00); // Set all of bank A to outputs
Wire.endTransmission();
}

/**
*/
void toggleLatchChannel(byte channelId)
{
if( channelId >= 1 && channelId <= 8 )
{
byte shieldOutput = channelId;
byte channelMask = 1 << (shieldOutput - 1);
shield1BankA = shield1BankA ^ channelMask;
sendRawValueToLatch1(shield1BankA);
}
else if( channelId >= 9 && channelId <= 16 )
{
byte shieldOutput = channelId - 8;
byte channelMask = 1 << (shieldOutput - 1);
shield2BankA = shield2BankA ^ channelMask;
sendRawValueToLatch2(shield2BankA);
}
}

/**
*/
void setLatchChannelOn (byte channelId)
{
if( channelInterlocks == true )
{
if ( (channelId % 2) == 0) // This is an even number channel, so turn off the channel before it
{
setLatchChannelOff( channelId - 1 );
} else { // This is an odd number channel, so turn off the channel after it
setLatchChannelOff( channelId + 1 );
}
}

if( channelId >= 1 && channelId <= 8 )
{
byte shieldOutput = channelId;
byte channelMask = 1 << (shieldOutput - 1);
shield1BankA = shield1BankA | channelMask;
sendRawValueToLatch1(shield1BankA);
}
else if( channelId >= 9 && channelId <= 16 )
{
byte shieldOutput = channelId - 8;
byte channelMask = 1 << (shieldOutput - 1);
shield2BankA = shield2BankA | channelMask;
sendRawValueToLatch2(shield2BankA);
}
}

/**
*/
void setLatchChannelOff (byte channelId)
{
if( channelId >= 1 && channelId <= 8 )
{
byte shieldOutput = channelId;
byte channelMask = 255 - ( 1 << (shieldOutput - 1));
shield1BankA = shield1BankA & channelMask;
sendRawValueToLatch1(shield1BankA);
}
else if( channelId >= 9 && channelId <= 16 )
{
byte shieldOutput = channelId - 8;
byte channelMask = 255 - ( 1 << (shieldOutput - 1));
shield2BankA = shield2BankA & channelMask;
sendRawValueToLatch2(shield2BankA);
}
}

/**
*/
void sendRawValueToLatch1(byte rawValue)
{
Wire.beginTransmission(SHIELD_1_I2C_ADDRESS);
Wire.write(0x12); // Select GPIOA
Wire.write(rawValue); // Send value to bank A
shield1BankA = rawValue;
Wire.endTransmission();
}

/**
*/
void sendRawValueToLatch2(byte rawValue)
{
Wire.beginTransmission(SHIELD_2_I2C_ADDRESS);
Wire.write(0x12); // Select GPIOA
Wire.write(rawValue); // Send value to bank A
shield2BankA = rawValue;
Wire.endTransmission();
}

/**

  • Required to read the MAC address ROM
    */
    byte readRegister(byte r)
    {
    unsigned char v;
    Wire.beginTransmission(MAC_I2C_ADDRESS);
    Wire.write®; // Register to read
    Wire.endTransmission();

Wire.requestFrom(MAC_I2C_ADDRESS, 1); // Read a byte
while(!Wire.available())
{
// Wait
}
v = Wire.read();
return v;
}

not all of it is mine so im trying to piece this together. i should be able to publish into /relay/power/1/01 ‘on’ or ‘off’ and that should trigger the relay. am i missing something here?

@chris something you could possibly help me with?
Thanks again for your help

2

I’ll have a proper look this weekend, that’s a lot of code!

1 Like
3

Rewrote my code @chris

after spending the last 3hrs bashing my head against a wall its finally working

turns out
Wire.begin(); // Wake up the I2C Bus

is actually needed, i just forgot that part somehow.

Hopefully me bashing my head against a wall helps others who may need this

   // This subscribes to MQTT IOT get the PIR sensor states //

#include <SPI.h>
#include <Ethernet.h>
#include <PubSubClient.h>
#include <Wire.h>

#define SHIELD_1_I2C_ADDRESS  0x20  // 0x20 is the address with all jumpers removed
#define SHIELD_2_I2C_ADDRESS  0x21  // 0x21 is the address with a jumper on position A0
#define MAC_I2C_ADDRESS       0x50  // Microchip 24AA125E48 I2C ROM address

// Update these with values suitable for your network.
byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
IPAddress ip(192, 168, 1, 67);
IPAddress server(192, 168, 1, 108);

byte shield1BankA = 0; // Current status of all outputs on first shield, one bit per output
byte shield2BankA = 0; // Current status of all outputs on second shield, one bit per output

void callback(char* topic, byte* payload, unsigned int length) {
  // handle message arrived
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();


  if (strcmp(topic, "relay1") == 0) {
    if ((char)payload[0] == '1')
    {
      setLatchChannelOn(1);
      delay(100);   // not actually needed, but i added this in here for how my lights work
      Serial.println("Relay 1 triggered ON");
      
    }
    else if ((char)payload[0] == '0')
    {
      setLatchChannelOff(1);
      Serial.println("Relay 1 triggered OFF");
    }
  }
}



EthernetClient ethClient;
PubSubClient client(server, 1883, callback, ethClient);

void setup()
{
  Wire.begin(); // Wake up the I2C Bus
  Serial.begin(38400);
  Ethernet.begin(mac, ip);
  // Note - the default maximum packet size is 128 bytes. If the
  // combined length of clientId, username and password exceed this,
  // you will need to increase the value of MQTT_MAX_PACKET_SIZE in
  // PubSubClient.h

/* Set up the Relay8 shields */
  initialiseShield(SHIELD_1_I2C_ADDRESS);
  sendRawValueToLatch1(0);  // If we don't do this, channel 6 turns on! I don't know why
  
  initialiseShield(SHIELD_2_I2C_ADDRESS);
  sendRawValueToLatch2(0);  // If we don't do this, channel 6 turns on! I don't know why
 Serial.println("Ready.");
}

void reconnect() {
// Loop until we're reconnected
while (!client.connected()) {
  Serial.print("Attempting MQTT connection...");
  // Attempt to connect
  if (client.connect("arduinoClient", "openhabian", "openhabian")) {
    Serial.println("connected");
    client.subscribe("relay1");

  } else {
    Serial.print("failed, rc=");
    Serial.print(client.state());
    Serial.println(" try again in 5 seconds");
    // Wait 5 seconds before retrying
    delay(5000);
   }
 }
}
void loop()
{
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
}

void initialiseShield(int shieldAddress)
{
  // Set addressing style
  Wire.beginTransmission(shieldAddress);
  Wire.write(0x12);
  Wire.write(0x20); // use table 1.4 addressing
  Wire.endTransmission();

  // Set I/O bank A to outputs
  Wire.beginTransmission(shieldAddress);
  Wire.write(0x00); // IODIRA register
  Wire.write(0x00); // Set all of bank A to outputs
  Wire.endTransmission();
}

void setLatchChannelOn (byte channelId)
{
  if ( channelId >= 1 && channelId <= 8 )
  {
    byte shieldOutput = channelId;
    byte channelMask = 1 << (shieldOutput - 1);
    shield1BankA = shield1BankA | channelMask;
    sendRawValueToLatch1(shield1BankA);
  }
  else if ( channelId >= 9 && channelId <= 16 )
  {
    byte shieldOutput = channelId - 8;
    byte channelMask = 1 << (shieldOutput - 1);
    shield2BankA = shield2BankA | channelMask;
    sendRawValueToLatch2(shield2BankA);
  }
}

void setLatchChannelOff (byte channelId)
{
  if( channelId >= 1 && channelId <= 8 )
  {
    byte shieldOutput = channelId;
    byte channelMask = 255 - ( 1 << (shieldOutput - 1));
    shield1BankA = shield1BankA & channelMask;
    sendRawValueToLatch1(shield1BankA);
  }
  else if( channelId >= 9 && channelId <= 16 )
  {
    byte shieldOutput = channelId - 8;
    byte channelMask = 255 - ( 1 << (shieldOutput - 1));
    shield2BankA = shield2BankA & channelMask;
    sendRawValueToLatch2(shield2BankA);
  }
}

void sendRawValueToLatch1(byte rawValue)
{
  Wire.beginTransmission(SHIELD_1_I2C_ADDRESS);
  Wire.write(0x12);        // Select GPIOA
  Wire.write(rawValue);    // Send value to bank A
  shield1BankA = rawValue;
  Wire.endTransmission();
}

void sendRawValueToLatch2(byte rawValue)
{
  Wire.beginTransmission(SHIELD_2_I2C_ADDRESS);
  Wire.write(0x12);        // Select GPIOA
  Wire.write(rawValue);    // Send value to bank A
  shield2BankA = rawValue;
  Wire.endTransmission();
}

/** Required to read the MAC address ROM */
byte readRegister(byte r)
{
  unsigned char v;
  Wire.beginTransmission(MAC_I2C_ADDRESS);
  Wire.write(r);  // Register to read
  Wire.endTransmission();

  Wire.requestFrom(MAC_I2C_ADDRESS, 1); // Read a byte
  while (!Wire.available())
  {
    // Wait
  }
  v = Wire.read();
  return v;
}

At least you wont need to read all that code now :heart:

3 Likes
4

Hi Bedrock,

In your code - how do you send channelID to the arduino?
If I send it like this from my client:
mosquitto_pub -h 10.10.10.100 -t “relay1” -m “1” -u username -P password

In serial monitor I can see that message 1 is arrived, but relay isn’t triggered. Cannot fully understand how do you pass values to relay 2, 3, etc.

Thanks.

5

if its appearing in the serial monitor sounds like its not initializing the I2C bus
you do have Wire.begine(); at the start of void setup()?

as for the relays the way i have done mine is a but different this is all you need for the triggering of the relay

if (strcmp(topic, “relay1”) == 0) {
if ((char)payload[0] == ‘1’)
{
setLatchChannelOn(1);
delay(100); // not actually needed, but i added this in here for how my lights work
Serial.println(“Relay 1 triggered ON”);
}
else if ((char)payload[0] == ‘0’)
{
setLatchChannelOff(1);
Serial.println(“Relay 1 triggered OFF”);
}
}

so if you had 2 relays it would looks like this
if its appearing in the serial monitor sounds like its not initializing the I2C bus
you do have Wire.begin(); at the start of void setup()?

as for the relays the way i have done mine is a but different this is all you need for the triggering of the relay

if (strcmp(topic, “relay1”) == 0) {
if ((char)payload[0] == ‘1’)
{
setLatchChannelOn(1);
delay(100); // not actually needed, but i added this in here for how my lights work
Serial.println(“Relay 1 triggered ON”);
}
else if ((char)payload[0] == ‘0’)
{
setLatchChannelOff(1);
Serial.println(“Relay 1 triggered OFF”);
}
}

so if you had 2 relays it would looks like this

if (strcmp(topic, “relay1”) == 0) {
if ((char)payload[0] == ‘1’)
{
setLatchChannelOn(1);
delay(100); // not actually needed, but i added this in here for how my lights work
Serial.println(“Relay 1 triggered ON”);
}
else if ((char)payload[0] == ‘0’)
{
setLatchChannelOff(1);
Serial.println(“Relay 1 triggered OFF”);
}
}
if (strcmp(topic, “relay2”) == 0) {
if ((char)payload[0] == ‘1’)
{
setLatchChannelOn(2);
delay(100); // not actually needed, but i added this in here for how my lights work
Serial.println(“Relay 2 triggered ON”);
}
else if ((char)payload[0] == ‘0’)
{
setLatchChannelOff(2);
Serial.println(“Relay 2 triggered OFF”);
}
}

the in Void Reconnect()

add another line for Relay2
client.subscribe("relay2");

i recommend getting MQTT.fx

it will show you more on what is happening on your MQTT server.

hopefully that answers your question a bit more

1 Like