Files
OpenMQTT-Gateway/ZsensorBH1750.ino
T
Florian da859cc6ae Some memory optimization for Arduino UNO following this thread:
https://community.openmqttgateway.com/t/arduino-uno-ethernet-shield-reboots-on-receiving-rf-signal-on-v-0-9/346/22
Rework led management to avoid use of global variables
and specify special JSON_MSG_BUFFER for arduino UNO
led can now be used for all the boards

generalize use of F macro
for memory optimization
change jsonbuffer calculation method
reduce pubsubclient max packet size for uno and nano
2019-03-09 17:28:54 +01:00

129 lines
4.3 KiB
Arduino

/*
OpenMQTTGateway Addon - ESP8266 or Arduino program for home automation
Act as a wifi or ethernet gateway between your 433mhz/infrared IR signal and a MQTT broker
Send and receiving command by MQTT
This is the Light Meter Addon:
- Measures ambient Light Intensity in Lux (lx), Foot Candela (ftcd) and Watt/m^2 (wattsm2)
- Required Hardware Module: BH1750
Connection Schemata:
--------------------
BH1750 ------> Arduino Uno ----------> ESP8266
==============================================
Vcc ---------> 5V -------------------> Vu (5V)
GND ---------> GND ------------------> GND
SCL ---------> Pin A5 ---------------> D1
SDA ---------> Pin A4 ---------------> D2
ADD ---------> N/C (Not Connected) --> N/C (Not Connected)
Copyright: (c) Hans-Juergen Dinges
This file is part of OpenMQTTGateway.
OpenMQTTGateway is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OpenMQTTGateway is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifdef ZsensorBH1750
#include "math.h" // Library for trig and exponential functions
#include "Wire.h" // Library for communication with I2C / TWI devices
void setupZsensorBH1750()
{
Wire.begin();
Wire.beginTransmission(BH1750_i2c_addr);
Wire.write(0x10); // Set resolution to 1 Lux
Wire.endTransmission();
delay(300);
}
// void loop()
void MeasureLightIntensity()
{
if (millis() > (timebh1750 + TimeBetweenReadingBH1750)) {//retriving value of Lux, FtCd and Wattsm2 from BH1750
trc(F("Creating BH1750 buffer"));
const int JSON_MSG_CALC_BUFFER = JSON_OBJECT_SIZE(3);
StaticJsonBuffer<JSON_MSG_CALC_BUFFER> jsonBuffer;
JsonObject& BH1750data = jsonBuffer.createObject();
timebh1750 = millis();
unsigned int i=0;
static float persistedll;
static float persistedlf;
static float persistedlw;
unsigned int Lux;
float ftcd;
float Wattsm2;
// Check if reads failed and exit early (to try again).
Wire.requestFrom(BH1750_i2c_addr, 2);
if(Wire.available() != 2) {
trc(F("Failed to read from LightSensor BH1750!"));
}else{
i = Wire.read();
i <<=8;
i |= Wire.read();
// Calculate the Values
Lux = i/1.2; // Convert to Lux
ftcd = Lux/10.764;
Wattsm2 = Lux/683.0;
/*
Useful Information ;-)
lux (lx) # 1 lx = 1 lm/m² = 1 cd·sr·m⁻².
meter-candle (m-cd) # 1 m·cd = 1 lx = 1 lm/m² = 1 cd·sr·m⁻².
centimeter-candle (cm-sd) # 1 m·cd = 1 lx = 1 lm/m² = 1 cd·sr·m⁻².
foot-candle (ft-c) #
phot (ph) # 1 ph = 1 lm/cm² = 10,000 lm/m² - 10,000 lx = 10 klx
nox (nx) # 1 nox = 1 millilux
candela steradin/meter2(cd·sr·m⁻²) # 1 lx = 1 lm/m² = 1 cd·sr·m⁻²
lumen/meter2 (lm·m⁻²) # 1 lx = 1 lm/m² = 1 cd·sr·m⁻²
lumen/centimeter2 (lm·cm⁻²) # 1 lm/cm² = 10,000 lx = 10,000 cd·sr·m⁻²
lumen/foot2 (lm·ft⁻²) # (lm·ft⁻²)
watt/centimeter2 at 555nm (W·cm⁻²) #
*/
// Generate Lux
if(Lux != persistedll || bh1750_always){
BH1750data.set("lux", (unsigned int)Lux);
}else{
trc(F("Same lux don't send it"));
}
// Generate FtCd
if(ftcd != persistedlf || bh1750_always){
BH1750data.set("ftcd", (unsigned int)ftcd);
}else{
trc(F("Same ftcd don't send it"));
}
// Generate Watts/m2
if(Wattsm2 != persistedlw || bh1750_always){
BH1750data.set("wattsm2", (unsigned int)Wattsm2);
}else{
trc(F("Same wattsm2 don't send it"));
}
if(BH1750data.size()>0) pub(subjectBH1750toMQTT,BH1750data);
}
persistedll = Lux;
persistedlf = ftcd;
persistedlw = Wattsm2;
}
}
#endif