Mysensors si7021 sketch

[Tommas]

Dear All!

Has anybody a sketch for this temperature and humidity sensor? I would like to use it with mini pro combined easypcb board.

Thank you in advance!

[sundberg84]

@Tommas - some resources i found.

https://forum.mysensors.org/topic/2432/si7021-multisensor-first-try
https://github.com/mysensors/MySensorsArduinoExamples/tree/master/libraries/SI7021
https://forum.mysensors.org/topic/6434/solved-problems-with-an-si7021-temp-humidity-sensor/3

[Tommas]

Dear @sundberg84

Thanks for the suggestions!
Another, which pin should i connect to the si7021? I cant find this info...

Thanks,

[mfalkvidd]

@Tommas the si7021 uses i2c so you can use the wiring described at https://www.mysensors.org/build/light-bh1750 which also is an i2c device.

[Tommas]

Dear @mfalkvidd !

Thank you, and to everyone for the help!
I got it work!
If the sketch will be completed i will upload that!

[Tommas]

@sundberg84

What is the problem with my sketch? It is in developement phase, but the reading stops at this line, but sometimes it works for 3-4 loop...

" DEBUG_PRINTLN("Send TEMP and HUM started"); "

/**
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
 * Copyright (C) 2013-2015 Sensnology AB
 * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 *******************************
 *
 * REVISION HISTORY
 * Version 1.0: Henrik EKblad
 * Version 1.1 - 2016-07-20: Converted to MySensors v2.0 and added various improvements - Torben Woltjen (mozzbozz)
 * 
 * DESCRIPTION
 * This sketch provides an example of how to implement a humidity/temperature
 * sensor using a DHT11/DHT-22.
 *  
 * For more information, please visit:
 * http://www.mysensors.org/build/humidity
 * 
 */
#define MY_NODE_ID 4
// Enable debug prints
#define MY_DEBUG

// Enable and select radio type attached 
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69
//#define MY_RS485
/* Sketch with Si7021 and battery monitoring.
by m26872, 20151109 
*/
#include <MySensors.h>  
#include <Wire.h>
#include <SI7021.h>
#include <SPI.h>
#include <RunningAverage.h>

#define DEBUG

#ifdef DEBUG
#define DEBUG_SERIAL(x) Serial.begin(x)
#define DEBUG_PRINT(x) Serial.print(x)
#define DEBUG_PRINTLN(x) Serial.println(x)
#else
#define DEBUG_SERIAL(x)
#define DEBUG_PRINT(x) 
#define DEBUG_PRINTLN(x) 
#endif

#define NODE_ID 4             // <<<<<<<<<<<<<<<<<<<<<<<<<<<   Enter Node_ID
#define CHILD_ID_TEMP 0
#define CHILD_ID_HUM 1
//#define SLEEP_TIME 15000 // 15s for DEBUG
#define SLEEP_TIME 10000   // 5 min
//#define FORCE_TRANSMIT_CYCLE 36  // 5min*12=1/hour, 5min*36=1/3hour 
#define FORCE_TRANSMIT_CYCLE 1  // 5min*12=1/hour, 5min*36=1/3hour 
//#define BATTERY_REPORT_CYCLE 2880   // Once per 5min   =>   12*24*7 = 2016 (one report/week)
//#define VMIN 1900
//#define VMAX 3300
#define HUMI_TRANSMIT_THRESHOLD 3.0  // THRESHOLD tells how much the value should have changed since last time it was transmitted.
#define TEMP_TRANSMIT_THRESHOLD 0.5
#define AVERAGES 2

//int batteryReportCounter = BATTERY_REPORT_CYCLE - 1;  // to make it report the first time.
int measureCount = 0;
float lastTemperature = -100;
int lastHumidity = -100;

RunningAverage raHum(AVERAGES);
SI7021 humiditySensor;

//MySensor gw;
MyMessage msgTemp(CHILD_ID_TEMP,V_TEMP); // Initialize temperature message
MyMessage msgHum(CHILD_ID_HUM,V_HUM);

void presentation(){

sendSketchInfo("Node 4, Temp,Hum sensor", "1.1"); 
  present(CHILD_ID_TEMP, S_TEMP);   // Present sensor to controller
  present(CHILD_ID_HUM, S_HUM);
  
}


void setup() {
  DEBUG_SERIAL(115200);    
  DEBUG_PRINTLN("Serial started");
  
  //DEBUG_PRINT("Voltage: ");
  //DEBUG_PRINT(readVcc()); 
  //DEBUG_PRINTLN(" mV");
/*
  delay(500);
  DEBUG_PRINT("Internal temp: ");
  DEBUG_PRINT(GetInternalTemp()); // Probably not calibrated. Just to print something.
  DEBUG_PRINTLN(" *C");
*/  
  delay(500); // Allow time for radio if power useed as reset
  //begin(NULL,NODE_ID);
  
  //DEBUG_PRINT("Node and "); DEBUG_PRINTLN("2 children presented.");
  
  raHum.clear();
  
}

void loop() {
  DEBUG_PRINTLN("Loop started"); 
  measureCount ++;
  
  bool forceTransmit = true;
  
  //if (measureCount > FORCE_TRANSMIT_CYCLE) {
  //forceTransmit = true; 
  //}
  sleep(SLEEP_TIME);
  sendTempHumidityMeasurements(forceTransmit);
  DEBUG_PRINTLN("Loop ended"); 
  }
/*********************************************
 * * Sends temperature and humidity from Si7021 sensor
 * Parameters
 * - force : Forces transmission of a value (even if it's the same as previous measurement)
 *********************************************/
void sendTempHumidityMeasurements(bool force) {
  bool tx = force;
  DEBUG_PRINTLN("Send TEMP and HUM started"); 
  si7021_env data = humiditySensor.getHumidityAndTemperature();
  float temperature = data.celsiusHundredths / 100.0;
  DEBUG_PRINT("T: ");DEBUG_PRINTLN(temperature);
  float diffTemp = abs(lastTemperature - temperature);
  DEBUG_PRINT(F("TempDiff :"));DEBUG_PRINTLN(diffTemp);
  //if (diffTemp > TEMP_TRANSMIT_THRESHOLD || tx) {
  send(msgTemp.set(temperature, 1));
  //lastTemperature = temperature;
  //measureCount = 0;
  DEBUG_PRINTLN("T sent!");
  //}
  
  int humidity = data.humidityPercent;
  DEBUG_PRINT("H: ");DEBUG_PRINTLN(humidity);
  raHum.addValue(humidity);
  humidity = raHum.getAverage();  // MA sample imply reasonable fast sample frequency
  float diffHum = abs(lastHumidity - humidity);  
  DEBUG_PRINT(F("HumDiff  :"));DEBUG_PRINTLN(diffHum); 
  //if (diffHum > HUMI_TRANSMIT_THRESHOLD || tx) {
  send(msgHum.set(humidity, 1));
  //lastHumidity = humidity;
  //measureCount = 0;
  DEBUG_PRINTLN("H sent!");
  //}

}

[sundberg84]

@Tommas - sorry, im not the code expert...
If it stops without any indication why it can be a power issue as well.

[Tommas]

@sundberg84

There arent any indication. Sometimes it works.... i tried another si7021 and same. Voltage is Ok. A connected the sda - A4 scl - A5 on easypcb board

Any idea?

[Yveaux]

@Tommas do you have pullups (around 10k) at sda & scl lines?

[Tommas]

Dear @Yveaux

I think that yes. The si7021 module has an smd 103 part on it. Maybe it is at the sda and scl but im not sure.

https://www.ebay.com/i/401364416322

Thanks

[Nca78]

Hello,

you are missing the sensor.begin() to initialize the sensor. Return value will tell you if initialization succeeded or not.

if (!sensor.begin()) {
#ifdef MY_DEBUG
    Serial.println("FAILED TO INIT SENSOR !!!!");
#endif
...
  }