[SOLVED] Multisensor Node stops working after some days...

[OliverDog]

Hi folks...

I have a multisensor node on my baby's room created with:

• Arduino Nano powered by wiring VIN from an old cell phone power adapter, which is connected on a wall switch, where I can turn it on and off easily if something is wrong...
• MQ-2 gas sensor
• DHT-11 for humidity and temp
• 1 channel Relay which is connected to a wall AC power to turn on/off a Humidifier.

When connected through the VIN it works during some days and them stop working as soon as I act the relay.
If I use the relay the same day I turn it for the first time, it works, but after 2 or 3 days it stops working.
When reseted, it sends the first value but when reach the relay presentation stop.

When powered by USB all works fine, because of that I have nothing on the serial monitor...

Is it a soldering problem in VIN terminal?
If it is a power problem, why is it intermittent?

This is my sketch:

#define MY_DEBUG
#define MY_RADIO_NRF24
#define MY_NODE_ID 10

#include <SPI.h>
#include <MySensors.h>
#include <DHT.h>  
#include <Bounce2.h>

#define RELAY_ON 0
#define RELAY_OFF 1
#define RELAY_MSG_ON 1
#define RELAY_MSG_OFF 0
#define RELAY_PIN  3
#define BUTTON_PIN  2
#define HUMIDITY_SENSOR_DIGITAL_PIN 5
#define MQ_SENSOR_ANALOG_PIN         (0)  //define which analog input channel you are going to use

#define RL_VALUE                     (1)     //define the load resistance on the board, in kilo ohms
#define RO_CLEAN_AIR_FACTOR          (9.83)  //RO_CLEAR_AIR_FACTOR=(Sensor resistance in clean air)/RO,
#define CALIBARAION_SAMPLE_TIMES     (50)    //define how many samples you are going to take in the calibration phase
#define CALIBRATION_SAMPLE_INTERVAL  (500)   //define the time interal(in milisecond) between each samples in the
#define READ_SAMPLE_INTERVAL         (50)    //define how many samples you are going to take in normal operation
#define READ_SAMPLE_TIMES            (5)     //define the time interal(in milisecond) between each samples in
#define GAS_LPG                      (0)
#define GAS_CO                       (1)
#define GAS_SMOKE                    (2)

#define CHILD_ID_TEMP 3
#define CHILD_ID_HUM 2
#define CHILD_ID_MQ 0
#define CHILD_ID_SWITCH 1

unsigned long SLEEP_TIME = 6000; // Sleep time between reads (in loops)
unsigned long sleeptimer = 5000;

DHT dht;
signed int lastTemp;
signed int lastHum;
int temp_correct;
int hum_correct;
int med_LPG;
int med_CO;
int med_SMOKE;
bool metric = true; 
Bounce debouncer = Bounce();
bool state;
bool initialValueSent = false;

float Ro = 10000.0;    // this has to be tuned 10K Ohm
int val = 0;           // variable to store the value coming from the sensor
int valMQ = 0;
int lastMQ = 0;
float LPGCurve[3]  =  {2.3,0.21,-0.47};   //two points are taken from the curve.
float COCurve[3]  =  {2.3,0.72,-0.34};    //two points are taken from the curve.
float SmokeCurve[3] = {2.3,0.53,-0.44};   //two points are taken from the curve.

MyMessage msg(CHILD_ID_MQ, V_LEVEL);
MyMessage msgPrefix(CHILD_ID_MQ, V_UNIT_PREFIX);
MyMessage msgHum(CHILD_ID_HUM, V_HUM);
MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);
MyMessage msgSwitch(CHILD_ID_SWITCH, V_LIGHT);

void presentation()  
{ 
  sendSketchInfo("Baby", "1.0");
  wait(200);
  present(CHILD_ID_TEMP, S_TEMP);
  wait(200);
  present(CHILD_ID_HUM, S_HUM);
  wait(200);
  present(CHILD_ID_SWITCH, S_LIGHT);
  wait(200);
  present(CHILD_ID_MQ, S_AIR_QUALITY);
  metric = getControllerConfig().isMetric;
}

void setup()  
{ 
  pinMode(BUTTON_PIN, INPUT);
  digitalWrite(BUTTON_PIN, HIGH);
  debouncer.attach(BUTTON_PIN);
  debouncer.interval(5);

  // Make sure relays are off when starting up
  digitalWrite(RELAY_PIN, RELAY_OFF);
  pinMode(RELAY_PIN, OUTPUT);

  state = loadState(CHILD_ID_SWITCH);
  digitalWrite(RELAY_PIN, state?RELAY_ON:RELAY_OFF);
  
  dht.setup(HUMIDITY_SENSOR_DIGITAL_PIN); 
  wait(2000);
  signed int temperature = dht.getTemperature() + 0.5;
  wait(2000);
  signed int humidity = dht.getHumidity() + 0.5;
  wait(100);
  send(msgTemp.set(temperature));
  wait(100);
  send(msgHum.set(humidity));
  wait(100);
  send(msg.set("0"));

  Ro = MQCalibration(
           MQ_SENSOR_ANALOG_PIN);         //Calibrating the sensor. Please make sure the sensor is in clean air
  send(msgPrefix.set("GCF"));
}

void loop()  { 
  if (!initialValueSent) {
    Serial.println("Sending initial value");
    send(msgSwitch.set(state?RELAY_MSG_ON:RELAY_MSG_OFF));
    Serial.println("Requesting initial value from controller");
    request(CHILD_ID_SWITCH, V_STATUS);
    wait(2000, C_SET, V_STATUS);
  }
  bool changed = debouncer.update();
  int value = debouncer.read();
  if (changed && value==0) {
    // Send new state and request ack back
    send(msgSwitch.set(state?false:true), true);
  }
  
  if (sleeptimer > SLEEP_TIME)    {
    sleeptimer= 0;
    // Fetch temperatures from DHT sensor
    signed int temperature = dht.getTemperature() + 0.5;
    if (isnan(temperature)) {
        Serial.println("Failed reading temperature from DHT");
    } else if (temperature != lastTemp) {
      lastTemp = temperature;
      if (!metric) {
        temperature = dht.toFahrenheit(temperature) + 0.5;
      }
      int temp_correct = temperature * 1.08;
      send(msgTemp.set(temp_correct));
      #ifdef MY_DEBUG
      Serial.print("Temp: ");
      Serial.println(temperature);
      #endif
    }
    
    // Fetch humidity from DHT sensor
    signed int humidity = dht.getHumidity() + 0.5;
    if (isnan(humidity)) {
        Serial.println("Failed reading humidity from DHT");
    } else if (humidity != lastHum) {
      lastHum = humidity;
      int hum_correct = 2.7 * humidity - 0.015 * humidity * humidity - 31.125;
      send(msgHum.set(hum_correct));
      #ifdef MY_DEBUG
      Serial.print("Umid: ");
      Serial.println(humidity);
      #endif
    }

    // Air Sensor - I wanted a composed number to knowing what kind of gas is reported. Everything bellow 80 is reported as 0, and increases from 111, where each number is about a different gas
 
    med_LPG = ((int) (MQGetGasPercentage(MQRead(MQ_SENSOR_ANALOG_PIN)/Ro,GAS_LPG) + 80) / 80) * 100;
    med_CO = ((int) (MQGetGasPercentage(MQRead(MQ_SENSOR_ANALOG_PIN)/Ro,GAS_CO) + 80) / 80) * 10;
    med_SMOKE = ((int) (MQGetGasPercentage(MQRead(MQ_SENSOR_ANALOG_PIN)/Ro,GAS_SMOKE) + 80) / 80);
    valMQ = med_LPG + med_CO + med_SMOKE;
    if (valMQ != lastMQ) {
      if (valMQ < 112) {
        send(msg.set(0));
      } else send(msg.set(valMQ));
      lastMQ = valMQ;
      Serial.print("Gas (LPG CO SMOKE): ");
      Serial.println(valMQ);
    }
  } else sleeptimer++;
  wait(10);
}

void receive(const MyMessage &message) {
  if (message.isAck()) {
     Serial.println("This is an ack from gateway");
  }

  if (message.type == V_LIGHT) {
    if (!initialValueSent) {
      Serial.println("Receiving initial value from controller");
      initialValueSent = true;
    }
    // Change relay state
    state = message.getBool();
    digitalWrite(RELAY_PIN, state?RELAY_ON:RELAY_OFF);
    saveState(CHILD_ID_SWITCH, state);
    send(msgSwitch.set(state?RELAY_MSG_ON:RELAY_MSG_OFF));
  }
}


/****************** MQResistanceCalculation ****************************************
Input:   raw_adc - raw value read from adc, which represents the voltage
Output:  the calculated sensor resistance
Remarks: The sensor and the load resistor forms a voltage divider. Given the voltage
         across the load resistor and its resistance, the resistance of the sensor
         could be derived.
************************************************************************************/
float MQResistanceCalculation(int raw_adc)
{
  return ( ((float)RL_VALUE*(1023-raw_adc)/raw_adc));
}

/***************************** MQCalibration ****************************************
Input:   mq_pin - analog channel
Output:  Ro of the sensor
Remarks: This function assumes that the sensor is in clean air. It use
         MQResistanceCalculation to calculates the sensor resistance in clean air
         and then divides it with RO_CLEAN_AIR_FACTOR. RO_CLEAN_AIR_FACTOR is about
         10, which differs slightly between different sensors.
************************************************************************************/
float MQCalibration(int mq_pin)
{
  int i;
  float val=0;

  for (i=0; i<CALIBARAION_SAMPLE_TIMES; i++) {          //take multiple samples
    val += MQResistanceCalculation(analogRead(mq_pin));
    delay(CALIBRATION_SAMPLE_INTERVAL);
  }
  val = val/CALIBARAION_SAMPLE_TIMES;                   //calculate the average value

  val = val/RO_CLEAN_AIR_FACTOR;                        //divided by RO_CLEAN_AIR_FACTOR yields the Ro
  //according to the chart in the datasheet

  return val;
}
/*****************************  MQRead *********************************************
Input:   mq_pin - analog channel
Output:  Rs of the sensor
Remarks: This function use MQResistanceCalculation to caculate the sensor resistenc (Rs).
         The Rs changes as the sensor is in the different consentration of the target
         gas. The sample times and the time interval between samples could be configured
         by changing the definition of the macros.
************************************************************************************/
float MQRead(int mq_pin)
{
  int i;
  float rs=0;

  for (i=0; i<READ_SAMPLE_TIMES; i++) {
    rs += MQResistanceCalculation(analogRead(mq_pin));
    delay(READ_SAMPLE_INTERVAL);
  }

  rs = rs/READ_SAMPLE_TIMES;

  return rs;
}

/*****************************  MQGetGasPercentage **********************************
Input:   rs_ro_ratio - Rs divided by Ro
         gas_id      - target gas type
Output:  ppm of the target gas
Remarks: This function passes different curves to the MQGetPercentage function which
         calculates the ppm (parts per million) of the target gas.
************************************************************************************/
int MQGetGasPercentage(float rs_ro_ratio, int gas_id)
{
  if ( gas_id == GAS_LPG ) {
    return MQGetPercentage(rs_ro_ratio,LPGCurve);
  } else if ( gas_id == GAS_CO ) {
    return MQGetPercentage(rs_ro_ratio,COCurve);
  } else if ( gas_id == GAS_SMOKE ) {
    return MQGetPercentage(rs_ro_ratio,SmokeCurve);
  }

  return 0;
}

/*****************************  MQGetPercentage **********************************
Input:   rs_ro_ratio - Rs divided by Ro
         pcurve      - pointer to the curve of the target gas
Output:  ppm of the target gas
Remarks: By using the slope and a point of the line. The x(logarithmic value of ppm)
         of the line could be derived if y(rs_ro_ratio) is provided. As it is a
         logarithmic coordinate, power of 10 is used to convert the result to non-logarithmic
         value.
************************************************************************************/
int  MQGetPercentage(float rs_ro_ratio, float *pcurve)
{
  return (pow(10,( ((log10(rs_ro_ratio)-pcurve[1])/pcurve[2]) + pcurve[0])));
}

[gohan]

Don't you have any other power supply to try? What is the output current of that power supply you are using?

[OliverDog]

My power supply shows 900mah written on the case... can't measure because when tried with a multimeter, it stops the arduino power supply...

But to change the power I should decide first if it worth keep trying through VIN connection or change to USB, which will be easier because could use a phone adapter without any mod or soldering...

Does it do seem to be a power supply problem?

Thanks

[gohan]

if you have already a USB power supply, just try that and see what happens. It is quite strange that it stops the arduino when measuring the voltage

[OliverDog]

thanks @gohan I solved the problem by changing the power supply...

Now I'm powering through USB using a phone charger... so I'll never know if it was a soldering problem on VIN or a low current problem from the other disassembled phone charger... but it is working now...

Thanks for the help...

[gohan]

Arduino does not require a lot of current so it could have been an issue with wiring or the charger wasn't very stable