[James_NZ]

Thanks @shicks. COVID has meant that not everything is available at my end of the world, so I need to compromise sometimes!

[James_NZ]

Thanks @neilh20. I will definitely be interested in these when they are available.

@aufdenkampe do you have any feedback about YOSEMITECH turbidity sensors? My questions are:

1) Are they as reliable as other turbidity sensors, i.e. do they drift more readily, or provide strange values? For $510USD (non-wiper) or $680USD (wiper), they seem like a good deal.

2) Is it worth getting the wiper version over the non-wiper version?

3) We have a YSI multi-sonde deployed for another project using a modbus wing. Our technicians noted that the wiper powers on every-time the Mayfly connects to the probe, draining the battery. Is this the same for the YOSEMITECH sensors or is there a way around this?

3) How much does the RS485-to-TTL interface board cost to build?

Thanks for your help.

James

[James_NZ]

Hi @shicks.  I need a number of turbidity sensors for an upcoming project, and I have a reasonable quote from Yosemitech (~510USD each).  What additional interface hardware are you referring to for the Yosemitech probes?  Has anyone tested them and can vouch for their accuracy?

 

 

[James_NZ]

Hi everyone,

Just a quick update.  The 100k voltage divider worked perfectly. My new voltage water level relationship is below.

Thanks again for your help @shicks.

James
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Attachments:

1. 

   eTapeV2.png
   

[James_NZ]

Hi all,

Just an update. I sent an email to the tech support team at Millonetech, and we were able to confirm that the eTape sensor I am using is not a resistance to voltage module (as I suggested above), but contains a simple voltage divider. This version works fine with 5v VCC, so that is not a problem.

I purchased some 100k resistors and will build a 1/2 voltage divider tonight. I will let you know if I am successful at eliminating the strange behavior.

Thanks for your help.

James

[James_NZ]

Hi Shannon,

Yes using the Mayfly ver 0.5b.  I am using the ADS1115, and reading 50 ADS readings at 50us intervals and storing them in an array.  I am then taking the median of the array and multiplying by 3.3 before dividing the whole thing by 17585.0.

I have the Mayfly jumper on the ADC section set to 5v rather than 3.3.
It was my understanding that there is a voltage divider already built into the eTape.  Would I need to create another on top?

Relevant code is attached.

Thanks for your help.

James

// #include <Arduino.h> // The base Arduino library // // #define RESISTOR 1000 // #define SENSORPIN A1 // // // // // // void setup(void) { // Serial.begin(115200); // } // // // void loop(void) { // // float reading; // reading = analogRead(SENSORPIN); // // Serial.print("Analog reading "); // Serial.println(reading); // // reading = (1023 / reading) - 1; // (1023/ADC - 1) // reading = RESISTOR/ reading; // 10K / (1023/ADC - 1) // Serial.print("Sensor resistance "); // Serial.println(reading); // // delay(1000); // } #include <EnableInterrupt.h> // for external and pin change interrupts #include <LoggerBase.h> // The modular sensors library #include <Adafruit_ADS1015.h> #define eTapePin 2 //#define VREF 3.3 // analog reference voltage(Volt) of the ADC #define SENS_ON 22 Adafruit_ADS1115 ads; #define SCOUNT 40 // number of sample points to collect for averaging // the value of the 'other' resistor //#define SERIESRESISTOR 1000 // What pin to connect the sensor to //#define SENSORPIN A0 void setup(void) { Serial.begin(115200); ads.begin(); pinMode(eTapePin,INPUT); digitalWrite(SENS_ON, HIGH); } void loop(void) { float reading; float voltage; int analogBuffer[SCOUNT]; // store the analog value in the array, read from ADC int analogBufferTemp[SCOUNT]; int analogBufferIndex = 0, copyIndex = 0; while (analogBufferIndex < SCOUNT) // read the sensor every 50 milliseconds, SCOUNT times and store in array { analogBuffer[analogBufferIndex] = ads.readADC_SingleEnded(eTapePin); //read the analog value and store into the buffer analogBufferIndex++; // if(analogBufferIndex == SCOUNT) delay(50u); //delay 50 milliseconds between taking sample } analogBufferIndex = 0; for(copyIndex=0;copyIndex<SCOUNT;copyIndex++) // for coppyIndex = 0 to SCOUNT-1 analogBufferTemp[copyIndex]= analogBuffer[copyIndex]; // copy analogBuffer to analogBufferTemp voltage = (getMedianNum(analogBufferTemp,SCOUNT) *3.3)/17585.0; // read the analog value, // // // convert the value to resistance //reading = (65536/reading) - 1; //reading = SERIESRESISTOR / reading; Serial.print("Sensor voltage: "); Serial.println(voltage,5); delay(1000); } // calculate a median for set of values in buffer float getMedianNum(int bArray[], int iFilterLen) { int bTab[iFilterLen]; for (byte i = 0; i<iFilterLen; i++) bTab[i] = bArray[i]; // copy input array into BTab[] array int i, j, bTemp; for (j = 0; j < iFilterLen - 1; j++) // put array in ascending order { for (i = 0; i < iFilterLen - j - 1; i++) { if (bTab[i] > bTab[i + 1]) { bTemp = bTab[i]; bTab[i] = bTab[i + 1]; bTab[i + 1] = bTemp; } } } if ((iFilterLen & 1) > 0) // check to see if iFilterlen is odd or even using & (bitwise AND) i.e if length &AND 1 is TRUE (>0) bTemp = bTab[(iFilterLen - 1) / 2]; // then then it is odd, and should take the central value else bTemp = (bTab[iFilterLen / 2] + bTab[iFilterLen / 2 - 1]) / 2; // if even then take aveage of two central values return bTemp; } //end getmedianNum // Liquid Level Sensor Sketch // Show the raw resistance values measured from an eTape liquid level sensor. // See details on the sensor at: // https://www.adafruit.com/products/1786 // Created by Tony DiCola // Released under an MIT license: http://opensource.org/licenses/MIT // // Configuration values: // #define SERIES_RESISTOR 1000 // Value of the series resistor in ohms. // #define SENSOR_PIN 1 // Analog pin which is connected to the sensor. // // // The following are calibration values you can fill in to compute the volume of measured liquid. // // To find these values first start with no liquid present and record the resistance as the // // ZERO_VOLUME_RESISTANCE value. Next fill the container with a known volume of liquid and record // // the sensor resistance (in ohms) as the CALIBRATION_RESISTANCE value, and the volume (which you've // // measured ahead of time) as CALIBRATION_VOLUME. // #define ZERO_VOLUME_RESISTANCE 0.00 // Resistance value (in ohms) when no liquid is present. // #define CALIBRATION_RESISTANCE 0.00 // Resistance value (in ohms) when liquid is at max line. // #define CALIBRATION_VOLUME 0.00 // Volume (in any units) when liquid is at max line. // // void setup(void) { // Serial.begin(9600); // } // // void loop(void) { // // Measure sensor resistance. // float resistance = readResistance(SENSOR_PIN, SERIES_RESISTOR); // Serial.print("Resistance: "); // Serial.print(resistance, 2); // Serial.println(" ohms"); // // Map resistance to volume. // float volume = resistanceToVolume(resistance, ZERO_VOLUME_RESISTANCE, CALIBRATION_RESISTANCE, CALIBRATION_VOLUME); // Serial.print("Calculated volume: "); // Serial.println(volume, 5); // // Delay for a second. // delay(1000); // } // // float readResistance(int pin, int seriesResistance) { // // Get ADC value. // float resistance = analogRead(pin); // // Convert ADC reading to resistance. // resistance = (1023.0 / resistance) - 1.0; // resistance = seriesResistance / resistance; // return resistance; // } // // float resistanceToVolume(float resistance, float zeroResistance, float calResistance, float calVolume) { // if (resistance > zeroResistance || (zeroResistance - calResistance) == 0.0) { // // Stop if the value is above the zero threshold, or no max resistance is set (would be divide by zero). // return 0.0; // } // // Compute scale factor by mapping resistance to 0...1.0+ range relative to maxResistance value. // float scale = (zeroResistance - resistance) / (zeroResistance - calResistance); // // Scale maxVolume based on computed scale factor. // return calVolume * scale; // }

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// #include <Arduino.h>  // The base Arduino library // // #define RESISTOR 1000 // #define SENSORPIN A1 // // // // // // void setup(void) { // Serial.begin(115200); // } // // // void loop(void) { // //   float reading; //   reading = analogRead(SENSORPIN); // //   Serial.print("Analog reading "); //   Serial.println(reading); // //   reading = (1023 / reading)  - 1;     // (1023/ADC - 1) //   reading = RESISTOR/ reading;  // 10K / (1023/ADC - 1) //   Serial.print("Sensor resistance "); //   Serial.println(reading); // //   delay(1000); // }         #include <EnableInterrupt.h>  // for external and pin change interrupts #include <LoggerBase.h>  // The modular sensors library #include <Adafruit_ADS1015.h>   #define eTapePin 2 //#define VREF 3.3      // analog reference voltage(Volt) of the ADC #define SENS_ON 22 Adafruit_ADS1115 ads; #define SCOUNT  40           // number of sample points to collect for averaging   // the value of the 'other' resistor //#define SERIESRESISTOR 1000 // What pin to connect the sensor to //#define SENSORPIN A0   void setup(void) {   Serial.begin(115200);   ads.begin();   pinMode(eTapePin,INPUT);   digitalWrite(SENS_ON, HIGH); }   void loop(void) {   float reading; float voltage;   int analogBuffer[SCOUNT];    // store the analog value in the array, read from ADC   int analogBufferTemp[SCOUNT];   int analogBufferIndex = 0,  copyIndex = 0;     while (analogBufferIndex < SCOUNT)   // read the sensor every 50 milliseconds, SCOUNT times and store in array     {        analogBuffer[analogBufferIndex] = ads.readADC_SingleEnded(eTapePin);    //read the analog value and store into the buffer        analogBufferIndex++; //         if(analogBufferIndex == SCOUNT)         delay(50u);  //delay 50 milliseconds between taking sample     }     analogBufferIndex = 0;       for(copyIndex=0;copyIndex<SCOUNT;copyIndex++)  // for coppyIndex = 0 to SCOUNT-1                analogBufferTemp[copyIndex]= analogBuffer[copyIndex]; // copy analogBuffer to analogBufferTemp       voltage = (getMedianNum(analogBufferTemp,SCOUNT) *3.3)/17585.0; // read the analog value,     //     // // convert the value to resistance     //reading = (65536/reading)  - 1;     //reading = SERIESRESISTOR / reading;     Serial.print("Sensor voltage: ");    Serial.println(voltage,5);     delay(1000); }           // calculate a median for set of values in buffer float getMedianNum(int bArray[], int iFilterLen) {     int bTab[iFilterLen];    for (byte i = 0; i<iFilterLen; i++) bTab[i] = bArray[i];                  // copy input array into BTab[] array    int i, j, bTemp;    for (j = 0; j < iFilterLen - 1; j++)        // put array in ascending order    {  for (i = 0; i < iFilterLen - j - 1; i++)        {  if (bTab[i] > bTab[i + 1])            {  bTemp = bTab[i];               bTab[i] = bTab[i + 1];               bTab[i + 1] = bTemp;             }         }    } if ((iFilterLen & 1) > 0)  // check to see if iFilterlen is odd or even using & (bitwise AND) i.e if length &AND 1 is TRUE (>0)      bTemp = bTab[(iFilterLen - 1) / 2];     // then then it is odd, and should take the central value else     bTemp = (bTab[iFilterLen / 2] + bTab[iFilterLen / 2 - 1]) / 2;  // if even then take aveage of two central values return bTemp; } //end getmedianNum                                       // Liquid Level Sensor Sketch   // Show the raw resistance values measured from an eTape liquid level sensor. // See details on the sensor at: //   https://www.adafruit.com/products/1786   // Created by Tony DiCola // Released under an MIT license: http://opensource.org/licenses/MIT   // // Configuration values: // #define SERIES_RESISTOR     1000    // Value of the series resistor in ohms. // #define SENSOR_PIN          1      // Analog pin which is connected to the sensor. // // // The following are calibration values you can fill in to compute the volume of measured liquid. // // To find these values first start with no liquid present and record the resistance as the // // ZERO_VOLUME_RESISTANCE value.  Next fill the container with a known volume of liquid and record // // the sensor resistance (in ohms) as the CALIBRATION_RESISTANCE value, and the volume (which you've // // measured ahead of time) as CALIBRATION_VOLUME. // #define ZERO_VOLUME_RESISTANCE    0.00    // Resistance value (in ohms) when no liquid is present. // #define CALIBRATION_RESISTANCE    0.00    // Resistance value (in ohms) when liquid is at max line. // #define CALIBRATION_VOLUME        0.00    // Volume (in any units) when liquid is at max line. // // void setup(void) { // Serial.begin(9600); // } // // void loop(void) { // // Measure sensor resistance. // float resistance = readResistance(SENSOR_PIN, SERIES_RESISTOR); // Serial.print("Resistance: "); // Serial.print(resistance, 2); // Serial.println(" ohms"); // // Map resistance to volume. // float volume = resistanceToVolume(resistance, ZERO_VOLUME_RESISTANCE, CALIBRATION_RESISTANCE, CALIBRATION_VOLUME); // Serial.print("Calculated volume: "); // Serial.println(volume, 5); // // Delay for a second. // delay(1000); // } // // float readResistance(int pin, int seriesResistance) { // // Get ADC value. // float resistance = analogRead(pin); // // Convert ADC reading to resistance. // resistance = (1023.0 / resistance) - 1.0; // resistance = seriesResistance / resistance; // return resistance; // } // // float resistanceToVolume(float resistance, float zeroResistance, float calResistance, float calVolume) { // if (resistance > zeroResistance || (zeroResistance - calResistance) == 0.0) { //   // Stop if the value is above the zero threshold, or no max resistance is set (would be divide by zero). //   return 0.0; // } // // Compute scale factor by mapping resistance to 0...1.0+ range relative to maxResistance value. // float scale = (zeroResistance - resistance) / (zeroResistance - calResistance); // // Scale maxVolume based on computed scale factor. // return calVolume * scale; // }

 

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[James_NZ]

Hi Sara,

I worked through this and everything compiles correctly now!  Thanks for your help.

I did wonder about the linter in Atom.  From what I have read there seems to be an issue with linters working with .ino files in Atom.  Have you guys found anything that works?

James

 

 

[James_NZ]

Thanks @srgdamiano! I will try again when I get home from work.

I am using Atom with PlatformIO. How do I turn the linter tools on? thanks also for the tip on ‘extVoltage’. I was going to write a function that did the same thing as the unnecessary repetition was starting to bug me!

James

[James_NZ]

Hi Scott @ensign,

Thank you for this, and apologies for not getting back to you sooner.  For some reason I wasn’t alerted to your reply.

This is exactly what I was after!

Thanks again.  I will let you know how we get on.

James

[James_NZ]

Haha, that worked! Thanks @mbarney.

[Author]

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