Water pressure sensor

[lekeb]

Hello,

I need your help to write my first "My sensor" sketch.
I use this 5V sensor (link below) and pro-mini arduino to mesure water pressure inside my home water pipe.
https://fr.aliexpress.com/item/0-0-5-Mpa-Water-Gas-Pressure-Sensor-G1-4-DC-5V-Air-Compressor-Pressure-Transmitter/32660132491.html?spm=a2g0s.9042311.0.0.KxZ6lv

I used this simple sketch to read water pressure in Bar. I can read a pressure around 2.20 Bar

void setup() {
  Serial.begin(9600);
}

void loop() {
int lecture_adc;
float pression;

lecture_adc = analogRead(A0);
Serial.print("Sensor Value: ");
Serial.println(lecture_adc);
pression = (((lecture_adc*5/1024.0)-0.52)/1.7); //read pressure in Bar, remove 1.7 to read Voltage, divide 0.17 to read in  MPa        
Serial.print("Pression: ");
Serial.println(pression);

delay(1000);

Now, I tried to monitore my water pressure with my sensor and domoticz, that's why I wrote this sketch

// Enable debug prints to serial monitor
#define MY_DEBUG 

// Enable and select radio type attached
#define MY_RADIO_NRF24

#define MY_NODE_ID 7

#include <MySensors.h>

#define BARO_CHILD 0
#define BAR_SENSOR_ANALOG_PIN 0

unsigned long SLEEP_TIME = 60000;

MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
void setup(){
  
}

void presentation() {
  sendSketchInfo("pressure Sensor", "1.0");
  present(BARO_CHILD, S_BARO);
}

void loop() {
  int lecture_adc;
  float pression;

  lecture_adc = BAR_SENSOR_ANALOG_PIN;
  pression = ((lecture_adc*5/1024.0)-0.52)/1.7;
  Serial.println(pression);        
  send(pressureMsg.set(pression, 2));
        
  sleep(SLEEP_TIME);
}

But with this code, my node send as value -0.21 (check in DEBUG). I don't understand why.
Could you help me to understand what is wrong?

Thanks

[mfalkvidd]

Welcome to the MySensors community @lekeb Congratulations on your first node :)

Do you mean that

Serial.println(pression); 

prints the correct value, but

send(pressureMsg.set(pression, 2));

results in .0.21?

Could you post the full debug output?

[lekeb]

Thanks for your answer.

Exactly, I don't get the same value

Here my full debug

0 MCO:BGN:INIT NODE,CP=RNNNA--,VER=2.1.1
3 TSM:INIT
4 TSF:WUR:MS=0
11 TSM:INIT:TSP OK
12 TSM:INIT:STATID=7
14 TSF:SID:OK,ID=7
16 TSM:FPAR
35 TSF:MSG:SEND,7-7-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
2042 !TSM:FPAR:NO REPLY
2044 TSM:FPAR
2063 TSF:MSG:SEND,7-7-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
2071 TSF:MSG:READ,0-0-7,s=255,c=3,t=8,pt=1,l=1,sg=0:0
2076 TSF:MSG:FPAR OK,ID=0,D=1
4071 TSM:FPAR:OK
4072 TSM:ID
4073 TSM:ID:OK
4075 TSM:UPL
4077 TSF:MSG:SEND,7-7-0-0,s=255,c=3,t=24,pt=1,l=1,sg=0,ft=0,st=OK:1
4083 TSF:MSG:READ,0-0-7,s=255,c=3,t=25,pt=1,l=1,sg=0:1
4088 TSF:MSG:PONG RECV,HP=1
4091 TSM:UPL:OK
4092 TSM:READY:ID=7,PAR=0,DIS=1
4097 TSF:MSG:SEND,7-7-0-0,s=255,c=3,t=15,pt=6,l=2,sg=0,ft=0,st=OK:0100
4104 TSF:MSG:READ,0-0-7,s=255,c=3,t=15,pt=6,l=2,sg=0:0100
4110 TSF:MSG:SEND,7-7-0-0,s=255,c=0,t=17,pt=0,l=5,sg=0,ft=0,st=OK:2.1.1
4118 TSF:MSG:SEND,7-7-0-0,s=255,c=3,t=6,pt=1,l=1,sg=0,ft=0,st=OK:0
4128 TSF:MSG:READ,0-0-7,s=255,c=3,t=6,pt=0,l=1,sg=0:M
4134 TSF:MSG:SEND,7-7-0-0,s=255,c=3,t=11,pt=0,l=15,sg=0,ft=0,st=OK:pressure Sensor
4144 TSF:MSG:SEND,7-7-0-0,s=255,c=3,t=12,pt=0,l=3,sg=0,ft=0,st=OK:1.0
4151 TSF:MSG:SEND,7-7-0-0,s=0,c=0,t=8,pt=0,l=0,sg=0,ft=0,st=OK:
4157 MCO:REG:REQ
4160 TSF:MSG:SEND,7-7-0-0,s=255,c=3,t=26,pt=1,l=1,sg=0,ft=0,st=OK:2
4166 TSF:MSG:READ,0-0-7,s=255,c=3,t=27,pt=1,l=1,sg=0:1
4171 MCO:PIM:NODE REG=1
4173 MCO:BGN:STP
4175 MCO:BGN:INIT OK,TSP=1
-0.29
4178 TSF:MSG:SEND,7-7-0-0,s=0,c=1,t=4,pt=7,l=5,sg=0,ft=0,st=OK:-0.29
4186 MCO:SLP:MS=60000,SMS=0,I1=255,M1=255,I2=255,M2=255
4191 MCO:SLP:TPD
4192 MCO:SLP:WUP=-1
-0.29
4196 TSF:MSG:SEND,7-7-0-0,s=0,c=1,t=4,pt=7,l=5,sg=0,ft=0,st=OK:-0.29
4202 MCO:SLP:MS=60000,SMS=0,I1=255,M1=255,I2=255,M2=255
4207 MCO:SLP:TPD```

[mfalkvidd]

@lekeb looks like you've forgotten analogRead :ghost:

[lekeb]

Makes sense! My value didn't change over time
But what means this ligne

#define BAR_SENSOR_ANALOG_PIN 0

I guessed it was to declare AnalogRead on pin 0?

[mickecarlsson]

Change

lecture_adc = BAR_SENSOR_ANALOG_PIN;

To

lecture_adc = analogRead(BAR_SENSOR_ANALOG_PIN);

[lekeb]

Thanks a lot, It works!!!

Here my code updated

// Enable debug prints to serial monitor
//#define MY_DEBUG 

// Enable and select radio type attached
#define MY_RADIO_NRF24

//#define MY_NODE_ID 7

#include <MySensors.h>

#define BARO_CHILD 0
#define BAR_SENSOR_ANALOG_PIN 0

unsigned long SLEEP_TIME = 60000;

MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
void setup(){
  
}

void presentation() {
  sendSketchInfo("pressure Sensor", "1.0");
  present(BARO_CHILD, S_BARO);
}

void loop() {
    
  int lecture_adc = analogRead(BAR_SENSOR_ANALOG_PIN);
  float pression = ((lecture_adc*5/1024.0)-0.50)/1.7;
  Serial.println(pression);        
  send(pressureMsg.set(pression, 2));
        
  sleep(SLEEP_TIME);
}

[dpancer]

@lekeb

How is your pressure sensor working out? are you getting accurate reading? I'm looking to hook up something similar to vera