VEML6070 and VEML6075 UV sensors

[alexsh1]

Hi,

I am building a UV reporting node.
I need to present the following:

• μW per cm²
• UV Index (0-11+)

What's the best pay to present it to GW and controller (Domoticz)?

• μW per cm² -> S_UV / V_UV
  -UV Index -> S_LIGHT_LEVEL/V_LIGHT_LEVEL???

Thanks
Alex

[scalz]

for the moment, if i'm not wrong, i'm using S_UV/V_UV for UV index. and temporarily S_POWER/V_WATT for uW/cm².
Also note, depending on usecase, VEML6075 is better regarding its voltage range (i'm using both)

[alexsh1]

@scalz So you are using a temp one as well for uW/cm2...

VEML6075 is a more complex one. I think it can differentiate UV-a and UV-b or something. I ordered it a short while ago, but it would take some time before it arrives. Right now I have to think where to place it so that (1) the battery sensor is water tight if placed externally (2) direct UV exposure to the sensor (3) a transparent lid? Possible to 3d print? (4) externally or internally?

[scalz]

@alexsh1 for type of msg, yep..
hehe i have some custom boards with this one :yum: I'm using it because of voltage range, one less part, and "new". UVA/UVB is a nice bonus then.
For the enclosure, i'm still thinking the best options regarding environments i want to use them.
If printing for outdoor, i would recommend PETG, ABS (more tricky), or better but more expensive ASA.

[alexsh1]

@scalz The sensor has got a certain angle (55 degrees half sensitivity if I remember correctly) to provide the correct reading so the ideal place for it would be a roof? This would put an extra hurdle on enclosure design.

I suppose it has to be outside. I can seal atmega328p with electronic leaving only the battery box and the sensor. However, as I said before designing the box is very tricky.

[alexsh1]

http://www.vishay.com/docs/84310/designingveml6070.pdf

Interesting info on the sensor

[tbowmo]

Normal transparent glass can apparently block up to 75% of UV-B..

So one should look into what to use as a window over the chip area..

[alexsh1]

@tbowmo correct. This is why it has to be placed outside. And the sensor must be exposed as well. We need to build MySensors watertight IP67 enclosure now :-)

[tbowmo]

@alexsh1

But you can not expose the sensor to rain etc. So you still need to have some cover above the chip, and this should be UV transparent..

[alexsh1]

@tbowmo As I have just discovered there is a UV transparent plastic.
Maybe the enclosure can be 3D printed with such plastic?

There is also a UV transparent glass.

[alexsh1]

The sensor has a peak
sensitivity at 355 nm.

UV Spectrum:
UV-a -> 315-400nm
UV-b -> 280-315nm
UV-c -> 100-280nm

UV-a goes through the glass and is a major one
UV-b account for only 3% of UV radiation
UV-c is absorbed by ozone layer

[scalz]

@alexsh1 so if i were you i would have bought a veml6075 when you ordered at some ic supplier! I'm joking.. or not ;)

[korttoma]

Anyone care to share a sketch that includes the VEML6075?

[alexsh1]

@korttoma I have not received VEML6075 yet so cannot help you

[scalz]

@korttoma what do you need exactly?? I can share some example, but there is nothing fancy for veml6075. On my side i'm using this lib for the moment https://github.com/schizobovine/VEML6075 , not digged much yet but it's working with MySensors of course. You simply need the same cooking in your sketch, as usual ;)

[korttoma]

Well, I'm looking to replace my Oregon Scientific UV Sensor UVN800 (that finally stopped reporting any values) by using a VEML6075 and a Sensebender Micro.

I can probably work out the code for the sketch myself but I'm not a fan of reinventing the wheel so if someone already created a sketch it would simply save me the time.

I would expect the sensor to report a UV Index value between 0 and 10 like the Oregon sensor did according to this -> https://www.epa.gov/sunsafety/uv-index-scale-1

The example in the Lib you mentioned @scalz seems to have the UV Index posibility

[alexsh1]

@korttoma this thread is about VEML6075 :-)
However, VEML6075 is more complex - it does report uv-a and uv-b. I do not think you'd get UVI from this sensor straight away, you'd need to do it in the sketch.

I can share the sketch after I get the sensor, write a code and convert it into MySensors

[scalz]

@korttoma oki, i agree with you about reinventing the wheel, but for big job. I think it's always better to know how to use the lib, so that's not a waste imho ;)

No time for the moment to check my bigger sketch and extract everything.

But in case you would like to try your new sensor, here a quick 5-10min conversion and mix of the lib example to mysensors uv. I wouldn't release it like this, not optimized, and untested version. But it's compiling, it should work :)

// Enable debug prints to serial monitor
#define MY_DEBUG

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

//#define MY_NODE_ID 10

#include <MySensors.h>

#include <VEML6075.h>


VEML6075 veml6075 = VEML6075();
bool sensorFound = false;

#define CHILD_ID_UVI 0
#define CHILD_ID_UVA 0
#define CHILD_ID_UVB 0

uint32_t SLEEP_TIME = 30*1000; // Sleep time between reads (in milliseconds)

MyMessage uviMsg(CHILD_ID_UVI, V_UV);
MyMessage uvaMsg(CHILD_ID_UVA, V_UV);
MyMessage uvbMsg(CHILD_ID_UVB, V_UV);


void presentation()
{
    // Send the sketch version information to the gateway and Controller
    sendSketchInfo("UV Sensor", "1.3");

    // Register all sensors to gateway (they will be created as child devices)
    present(CHILD_ID_UVI, S_UV);
    present(CHILD_ID_UVA, S_UV);
    present(CHILD_ID_UVB, S_UV);
}

void setup()
{
  if (!veml6075.begin()) {
    Serial.println(F("VEML6075 not found!"));
  } else 
    sensorFound = true;

}

void loop()
{
  if (sensorFound) {
    unsigned long lastSend =0;
    float uvi;
    float uva;
    float uvb;
    static float uviOld = -1;
    static float uvaOld = -1;
    static float uvbOld = -1;

    // Poll sensor
    veml6075.poll();

    uva = veml6075.getUVA();
    Serial.print(F("UVA = "));
    Serial.println(uva, 2);

    uvb = veml6075.getUVB();
    Serial.print(F("UVB = "));
    Serial.println(uvb, 2);

    uvi = veml6075.getUVIndex();
    Serial.print(F("UV Index = "));
    Serial.println(uvi, 1);

    uint16_t devid = veml6075.getDevID();
    Serial.print(F("Device ID = "));
    Serial.println(devid, HEX);

    Serial.println(F("----------------"));
    
    if (uvi != uviOld) {
        send(uviMsg.set(uvi,2));
        uviOld = uvi;
    }
    if (uva != uvaOld) {
        send(uvaMsg.set(uva,2));
        uvaOld = uva;
    }
    if (uvb != uvbOld) {
        send(uvbMsg.set(uvb,2));
        uvbOld = uvb;
    }    
  }

  sleep(SLEEP_TIME);
}

It simply read sensor, send messages, and sleep.

As you can see, it's possible to get the three values from the lib.

[korttoma]

Thanks for the sketch @scalz , I made an attempt at it myself also. I was not avare that V_UV and S_UV could be used so I had V/S_LIGHT_LEVEL but I changed it now. Seems to compile just fine. Just need to get it tested.

SensebenderMicroWithUVIndex:

/**
 * 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 - Thomas Bowman Mørch
 * 
 * DESCRIPTION
 * Default sensor sketch for Sensebender Micro module
 * Act as a temperature / humidity sensor by default.
 *
 * If A0 is held low while powering on, it will enter testmode, which verifies all on-board peripherals
 *  
 * Battery voltage is as battery percentage (Internal message), and optionally as a sensor value (See defines below)
 *
 *
 * Version 1.3 - Thomas Bowman Mørch
 * Improved transmission logic, eliminating spurious transmissions (when temperatuere / humidity fluctuates 1 up and down between measurements) 
 * Added OTA boot mode, need to hold A1 low while applying power. (uses slightly more power as it's waiting for bootloader messages)
 * 
 * Version 1.4 - Thomas Bowman Mørch
 * 
 * Corrected division in the code deciding whether to transmit or not, that resulted in generating an integer. Now it's generating floats as expected.
 * Simplified detection for OTA bootloader, now detecting if MY_OTA_FIRMWARE_FEATURE is defined. If this is defined sensebender automaticly waits 300mS after each transmission
 * Moved Battery status messages, so they are transmitted together with normal sensor updates (but only every 60th minute)
 * 
 */

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

// Define a static node address, remove if you want auto address assignment
#define MY_NODE_ID 27

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

// Enable to support OTA for this node (needs DualOptiBoot boot-loader to fully work)
//#define MY_OTA_FIRMWARE_FEATURE

#include <SPI.h>
#include <MySensors.h>
#include <Wire.h>
#include <SI7021.h>
#ifndef MY_OTA_FIRMWARE_FEATURE
#include "drivers/SPIFlash/SPIFlash.cpp"
#endif
#include <EEPROM.h>  
#include <sha204_lib_return_codes.h>
#include <sha204_library.h>
#include <RunningAverage.h>
#include <VEML6075.h>
//#include <avr/power.h>

// Uncomment the line below, to transmit battery voltage as a normal sensor value
//#define BATT_SENSOR    199

#define RELEASE "1.4"

#define AVERAGES 2

// Child sensor ID's
#define CHILD_ID_UVI    1
#define CHILD_ID_TEMP   2
#define CHILD_ID_HUM    3

// How many milli seconds between each measurement
#define MEASURE_INTERVAL 60000

// How many milli seconds should we wait for OTA?
#define OTA_WAIT_PERIOD 300

// FORCE_TRANSMIT_INTERVAL, this number of times of wakeup, the sensor is forced to report all values to the controller
#define FORCE_TRANSMIT_INTERVAL 30 

// When MEASURE_INTERVAL is 60000 and FORCE_TRANSMIT_INTERVAL is 30, we force a transmission every 30 minutes.
// Between the forced transmissions a tranmission will only occur if the measured value differs from the previous measurement

// HUMI_TRANSMIT_THRESHOLD tells how much the humidity should have changed since last time it was transmitted. Likewise with
// TEMP_TRANSMIT_THRESHOLD for temperature threshold.
#define HUMI_TRANSMIT_THRESHOLD 0.5
#define TEMP_TRANSMIT_THRESHOLD 0.5
#define UVI_TRANSMIT_THRESHOLD 0.1

// Pin definitions
#define TEST_PIN       A0
#define LED_PIN        A2
#define ATSHA204_PIN   17 // A3

VEML6075 veml6075 = VEML6075();

const int sha204Pin = ATSHA204_PIN;
atsha204Class sha204(sha204Pin);

SI7021 humiditySensor;
SPIFlash flash(8, 0x1F65);

// Sensor messages
MyMessage msgHum(CHILD_ID_HUM, V_HUM);
MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);
MyMessage msgUVI(CHILD_ID_UVI, V_UV);

#ifdef BATT_SENSOR
MyMessage msgBatt(BATT_SENSOR, V_VOLTAGE);
#endif

// Global settings
int measureCount = 0;
int sendBattery = 0;
boolean isMetric = true;
boolean highfreq = true;
boolean transmission_occured = false;

// Storage of old measurements
float lastTemperature = -100;
int lastHumidity = -100;
long lastBattery = -100;
int lastUVI = -100;

RunningAverage raHum(AVERAGES);

/****************************************************
 *
 * Setup code 
 *
 ****************************************************/
void setup() {
  
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);

  //Serial.begin(115200);
  //Serial.print(F("Sensebender Micro FW "));
  //Serial.print(RELEASE);
  //Serial.flush();

  // First check if we should boot into test mode

  pinMode(TEST_PIN,INPUT);
  digitalWrite(TEST_PIN, HIGH); // Enable pullup
  if (!digitalRead(TEST_PIN)) testMode();

  // Make sure that ATSHA204 is not floating
  pinMode(ATSHA204_PIN, INPUT);
  digitalWrite(ATSHA204_PIN, HIGH);
  
  digitalWrite(TEST_PIN,LOW);
  
  digitalWrite(LED_PIN, HIGH); 

  humiditySensor.begin();

  veml6075.begin();
  
  digitalWrite(LED_PIN, LOW);

  //Serial.flush();
  //Serial.println(F(" - Online!"));
  
  isMetric = getControllerConfig().isMetric;
  //Serial.print(F("isMetric: ")); Serial.println(isMetric);
  raHum.clear();
  sendTempHumidityMeasurements(false);
  sendBattLevel(false);
  
#ifdef MY_OTA_FIRMWARE_FEATURE  
  //Serial.println("OTA FW update enabled");
#endif

}

void presentation()  {
  sendSketchInfo("Sensebender Micro", RELEASE);

  present(CHILD_ID_UVI,S_UV);
  present(CHILD_ID_TEMP,S_TEMP);
  present(CHILD_ID_HUM,S_HUM);
    
#ifdef BATT_SENSOR
  present(BATT_SENSOR, S_POWER);
#endif
}


/***********************************************
 *
 *  Main loop function
 *
 ***********************************************/
void loop() {
  
  measureCount ++;
  sendBattery ++;
  bool forceTransmit = false;
  transmission_occured = false;
#ifndef MY_OTA_FIRMWARE_FEATURE
  if ((measureCount == 5) && highfreq) 
  {
    clock_prescale_set(clock_div_8); // Switch to 1Mhz for the reminder of the sketch, save power.
    highfreq = false;
  } 
#endif
  
  if (measureCount > FORCE_TRANSMIT_INTERVAL) { // force a transmission
    forceTransmit = true; 
    measureCount = 0;
  }
    
  sendTempHumidityMeasurements(forceTransmit);
/*  if (sendBattery > 60) 
  {
     sendBattLevel(forceTransmit); // Not needed to send battery info that often
     sendBattery = 0;
  }*/
#ifdef MY_OTA_FIRMWARE_FEATURE
  if (transmission_occured) {
      wait(OTA_WAIT_PERIOD);
  }
#endif

  sleep(MEASURE_INTERVAL);  
}


/*********************************************
 *
 * 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;

  si7021_env data = humiditySensor.getHumidityAndTemperature();

  veml6075.poll();

    float UVA = veml6075.getUVA();
    //Serial.print(F("UVA = "));
    //Serial.println(UVA, 2);

    float UVB = veml6075.getUVB();
    //Serial.print(F("UVB = "));
    //Serial.println(UVB, 2);

    float UVI = veml6075.getUVIndex();
    //Serial.print(F("UV Index = "));
    //Serial.println(UVI, 1);
  
  
  
  raHum.addValue(data.humidityPercent);
  
  float diffTemp = abs(lastTemperature - (isMetric ? data.celsiusHundredths : data.fahrenheitHundredths)/100.0);
  float diffHum = abs(lastHumidity - raHum.getAverage());

  float diffUVI = abs(lastUVI - UVI);

  //Serial.print(F("TempDiff :"));Serial.println(diffTemp);
  //Serial.print(F("HumDiff  :"));Serial.println(diffHum); 
  //Serial.print(F("UVIDiff  :"));Serial.println(diffUVI); 
  
  if (isnan(diffHum)) tx = true; 
  if (diffTemp > TEMP_TRANSMIT_THRESHOLD) tx = true;
  if (diffHum > HUMI_TRANSMIT_THRESHOLD) tx = true;
  if (diffUVI > UVI_TRANSMIT_THRESHOLD) tx = true;

  
  if (tx) {
    measureCount = 0;
    float temperature = (isMetric ? data.celsiusHundredths : data.fahrenheitHundredths) / 100.0;
     
    int humidity = data.humidityPercent;
    //Serial.print("T: ");Serial.println(temperature);
    //Serial.print("H: ");Serial.println(humidity);
    
    send(msgTemp.set(temperature,1));
    send(msgHum.set(humidity));
    send(msgUVI.set(UVI,2));
    lastTemperature = temperature;
    lastHumidity = humidity;
    lastUVI = UVI;
    transmission_occured = true;
    if (sendBattery > 60) {
     sendBattLevel(true); // Not needed to send battery info that often
     sendBattery = 0;
    }
  }
}

/********************************************
 *
 * Sends battery information (battery percentage)
 *
 * Parameters
 * - force : Forces transmission of a value
 *
 *******************************************/
void sendBattLevel(bool force)
{
  if (force) lastBattery = -1;
  long vcc = readVcc();
  if (vcc != lastBattery) {
    lastBattery = vcc;

#ifdef BATT_SENSOR
    float send_voltage = float(vcc)/1000.0f;
    send(msgBatt.set(send_voltage,3));
#endif

    // Calculate percentage

    vcc = vcc - 1900; // subtract 1.9V from vcc, as this is the lowest voltage we will operate at
    
    long percent = vcc / 14.0;
    sendBatteryLevel(percent);
    transmission_occured = true;
  }
}

/*******************************************
 *
 * Internal battery ADC measuring 
 *
 *******************************************/
long readVcc() {
  // Read 1.1V reference against AVcc
  // set the reference to Vcc and the measurement to the internal 1.1V reference
  #if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
    ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
  #elif defined (__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
    ADMUX = _BV(MUX5) | _BV(MUX0);
  #elif defined (__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
    ADcdMUX = _BV(MUX3) | _BV(MUX2);
  #else
    ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
  #endif  
 
  delay(2); // Wait for Vref to settle
  ADCSRA |= _BV(ADSC); // Start conversion
  while (bit_is_set(ADCSRA,ADSC)); // measuring
 
  uint8_t low  = ADCL; // must read ADCL first - it then locks ADCH  
  uint8_t high = ADCH; // unlocks both
 
  long result = (high<<8) | low;
 
  result = 1125300L / result; // Calculate Vcc (in mV); 1125300 = 1.1*1023*1000
  return result; // Vcc in millivolts
 
}

/****************************************************
 *
 * Verify all peripherals, and signal via the LED if any problems.
 *
 ****************************************************/
void testMode()
{
  uint8_t rx_buffer[SHA204_RSP_SIZE_MAX];
  uint8_t ret_code;
  byte tests = 0;
  
  digitalWrite(LED_PIN, HIGH); // Turn on LED.
  //Serial.println(F(" - TestMode"));
  //Serial.println(F("Testing peripherals!"));
  //Serial.flush();
  //Serial.print(F("-> SI7021 : ")); 
  //Serial.flush();
  
  if (humiditySensor.begin()) 
  {
    //Serial.println(F("ok!"));
    tests ++;
  }
  else
  {
    //Serial.println(F("failed!"));
  }
  //Serial.flush();

  //Serial.print(F("-> Flash : "));
  //Serial.flush();
  if (flash.initialize())
  {
    //Serial.println(F("ok!"));
    tests ++;
  }
  else
  {
    //Serial.println(F("failed!"));
  }
  //Serial.flush();

  
  //Serial.print(F("-> SHA204 : "));
  ret_code = sha204.sha204c_wakeup(rx_buffer);
  //Serial.flush();
  if (ret_code != SHA204_SUCCESS)
  {
    //Serial.print(F("Failed to wake device. Response: ")); Serial.println(ret_code, HEX);
  }
  //Serial.flush();
  if (ret_code == SHA204_SUCCESS)
  {
    ret_code = sha204.getSerialNumber(rx_buffer);
    if (ret_code != SHA204_SUCCESS)
    {
      //Serial.print(F("Failed to obtain device serial number. Response: ")); Serial.println(ret_code, HEX);
    }
    else
    {
      //Serial.print(F("Ok (serial : "));
      for (int i=0; i<9; i++)
      {
        if (rx_buffer[i] < 0x10)
        {
          //Serial.print('0'); // Because Serial.print does not 0-pad HEX
        }
        //Serial.print(rx_buffer[i], HEX);
      }
      //Serial.println(")");
      tests ++;
    }

  }
  //Serial.flush();

  //Serial.println(F("Test finished"));
  
  if (tests == 3) 
  {
    //Serial.println(F("Selftest ok!"));
    while (1) // Blink OK pattern!
    {
      digitalWrite(LED_PIN, HIGH);
      delay(200);
      digitalWrite(LED_PIN, LOW);
      delay(200);
    }
  }
  else 
  {
    //Serial.println(F("----> Selftest failed!"));
    while (1) // Blink FAILED pattern! Rappidly blinking..
    {
    }
  }  
}

[alexsh1]

This is the VEML6070 UV Index graph. The last day, I placed the sensor outside rather than behind my window. There is a huge difference :