Arduino ADC Channel Multiplexing

[imranahmed]

Please let me know that I want to connect two sensors with Arduino UNO,

1)ACS712 current sensor. (for Amperes).
2)LM324 op-amp as a Precision rectifier. (for Voltages).

but how to set ADC for measuring both (Amps/Volts) on ADC channels.

OR how to multiplex channels.

 

[MagicianT]

int Volt = analogRead(A0) <- voltage sensor connected to A0
int Amps = analogRead(A1) <- current sensor connected to A1
Two sensors would share a common Ground

 

[imranahmed]

Dear MagicianT,

I connected them as you mentioned in the post but the readings are changing very fast.

How to set it with calm display?

 

[MagicianT]

You are asking for help w/o posting your code, it doesn't make any sense, at least for human bean.
You cant start troubleshooting from this web-link:
https://openenergymonitor.org/emon/buildingblocks/how-to-build-an-arduino-energy-monitor

 

[imranahmed]

Please find the attached code.

#include "LedControlMS.h"
#include <Arduino.h>

#define CURRENT_SENSOR A0 // Analog input pin that sensor is attached to
#define VOLTAGE_SENSOR A1 // Analog input pin that sensor is attached to

/*
 Now we need a LedControl to work with.
 ***** These pin numbers will probably not work with your hardware *****
 pin 12 is connected to the DataIn pin 1 of MAX7219
 pin 11 is connected to the CLK pin 13 of MAX7219
 pin 10 is connected to LOAD pin 12  of MAX7219
 We have only a single MAX72XX.*/

LedControl lc=LedControl(12,11,10,1); 

byte dp0=0,dp1=0,dp2=0,dp3=0,dp4=0,dp5=0;
unsigned int dv1 = 0, dv3 = 0;
float dv = 0, dv2 = 0;
float amplitude_current;                 //amplitude current
float effective_value;                   //effective current 
int ones, tens, hundreds,ones1, tens1, hundreds1,thousands1;
byte dp0=0,dp1=0,dp2=0,dp3=0,dp4=0,dp5=0;

void setup()
{
 /*
   The MAX72XX is in power-saving mode on startup,
   we have to do a wakeup call
   */
  lc.shutdown(0,false);
  /* Set the brightness to a medium values */
  lc.setIntensity(0,15);
  /* and clear the display */
  lc.clearDisplay(0);
  
  pinMode(CURRENT_SENSOR, INPUT);
  pinMode(VOLTAGE_SENSOR, INPUT);
}

void Volts_Reading(void)
{
    unsigned int adc1 = analogRead(VOLTAGE_SENSOR);
   
    dv2 = adc1;      
    if(dv2 >= 0 && dv2 <= 9)
    {
    dv3 = dv2 * 100;    
    dp3 = 1; 
    dp4 = 0;
    dp5 = 0; 
    ones1 = dv3%10;
    tens1 = (dv3/10)%10;
    hundreds1 = (dv3/100)%10;  
    lc.setDigit(0,3,(byte)hundreds1,dp3);
    lc.setDigit(0,4,(byte)tens1,dp4);
    lc.setDigit(0,5,(byte)ones1,dp5);   
    } 
    else if(dv2 >= 10 && dv2 <= 99)
    {
    dv3 = dv2 * 10;  
    dp3 = 0;  
    dp4 = 1;
    dp5 = 0;
    ones1 = dv3%10;
    tens1 = (dv3/10)%10;
    hundreds1 = (dv3/100)%10;  
    lc.setDigit(0,3,(byte)hundreds1,dp3);
    lc.setDigit(0,4,(byte)tens1,dp4);
    lc.setDigit(0,5,(byte)ones1,dp5);
    } 
    else if(dv2 >= 100 && dv2 <= 999)
    {
    dv3 = dv2 * 1;  
    dp3 = 0;  
    dp4 = 0;
    dp5 = 0;
    ones1 = dv3%10;
    tens1 = (dv3/10)%10;
    hundreds1 = (dv3/100)%10;  
    lc.setDigit(0,3,(byte)hundreds1,dp3);
    lc.setDigit(0,4,(byte)tens1,dp4);
    lc.setDigit(0,5,(byte)ones1,dp5);
    }     
    else if(dv2 > 999)
    {    
    lc.setChar(0,3,'-',false);
    lc.setChar(0,4,'-',false);
    lc.setChar(0,5,'-',false);    
    }    
}

void Amps_Reading(void)
{
    int sensor_max;
    sensor_max = analogRead(CURRENT_SENSOR);
    amplitude_current=(float)(sensor_max-512)/1024*5/66*1000000;   // for 5A mode,you need to modify this with 20 A and 30A mode; 
    effective_value=(amplitude_current/1.414);                     // 05A = 185  
    dv = effective_value/1000;   //Divide by 1000       
    if(dv >= 0 && dv <= 9)
    {
    dv1 = dv * 100;  
    dp0 = 1;     
    dp1 = 0; 
    dp2 = 0; 
    ones = dv1%10;
    tens = (dv1/10)%10;
    hundreds = (dv1/100)%10;   
    lc.setDigit(0,0,(byte)hundreds,dp0);
    lc.setDigit(0,1,(byte)tens,dp1);
    lc.setDigit(0,2,(byte)ones,dp2);
    } 
    else if(dv >= 10 && dv <= 99)
    {
    dv1 = dv * 10;  
    dp0 = 0;
    dp1 = 1;  
    dp2 = 0;
    ones = dv1%10;
    tens = (dv1/10)%10;
    hundreds = (dv1/100)%10;   
    lc.setDigit(0,0,(byte)hundreds,dp0);
    lc.setDigit(0,1,(byte)tens,dp1);
    lc.setDigit(0,2,(byte)ones,dp2);
    } 
    else if(dv >= 100 && dv <= 999)
    {
    dv1 = dv * 1;
    dp0 = 0;
    dp1 = 0;  
    dp2 = 0;  
    ones = dv1%10;
    tens = (dv1/10)%10;
    hundreds = (dv1/100)%10;   
    lc.setDigit(0,0,(byte)hundreds,dp0);
    lc.setDigit(0,1,(byte)tens,dp1);
    lc.setDigit(0,2,(byte)ones,dp2);
    }
    else if(dv > 999)
    {
    lc.setChar(0,0,'-',false);
    lc.setChar(0,1,'-',false);
    lc.setChar(0,2,'-',false);
    }
    }
    
    
    void loop()
    {
    Volts_Reading();
    Amps_Reading();    
    }

 

[ud23]

I don't know what is the clock selection for ADC you can reduce the ADC clock or do with delays between updates.

  void loop()
    {
    Volts_Reading();
    Amps_Reading(); 
     delay(1000);   //use what ever makes your update smooth..
    }

http://www.microsmart.co.za/technical/2014/03/01/advanced-arduino-adc/