starmbi / hp_bh1750 Goto Github PK

to include the RP2040 fix from ladyada. Thanks!

https://github.com/Starmbi/hp_BH1750/wiki

On the first page of your general usage wiki, you have readLux where I believe you mean getLux, as readLux isn't in your library.

Love this library, thank you for making.

Thanks for the great work with this library.
For me it didn't work, and I'm guessing that this is based on the fact that I'm using an ESP32, and that Wire implementation is slightly different.
I think that based on the beginTransmission, requestFrom does not work in readValue.
After updating that to the following, it worked like a charm.
(main change: removed the beginTransmission/endTransmission, since that's not needed in the requestFrom/read construction)

unsigned int hp_BH1750::readValue()
{
const byte bytesRequested = 2;
byte buff[bytesRequested];

unsigned int req = _wire->requestFrom((int)_address, (int)bytesRequested); // request two bytes
if ((req == 0) || (req > bytesRequested))
{
_time = 999;
_value = 0;
return _value; // Sensor not found or other problem
}

unsigned int bytesRead=0;
while(bytesRead<req) {
if (_wire->available()) {
buff[bytesRead] = _wire->read(); // Receive one byte
bytesRead++;
}
}

_nReads++; // Inc the physically count of reads
_value = ((buff[0] << 8) | buff[1]);

unsigned long mil = millis();
if (_value > 0 && _time == 0)
_time = mil - _startMillis; // Conversion time
if (mil >= (_timeoutMillis) && (_time == 0))
_time = mil - _startMillis;
return _value;
}

For some reason I cannot get this to work on the S2, ill keep testing and see if I can gather any debug or crash data.

my serial out put just stops, so not sure what to do here..

This line is where my code just stops..
unsigned int req = _wire->requestFrom((int)_address, (int)2); // request two bytes

Any ideas welcome, pretty sure it worked on esp32, gonna test again, also all other i2c sensors work fine

I've been doing some tests with your library and noticed that the following occasionally breaks out of the following loop before the sensor has had enough time to gather a reading:

bh1750.adjustSettings(90,true);
bh1750.start();
do{
//...reading other non I2C sensors here & averaging....
} while(bh1750.hasValue(true) == false);
float lux_T1red= bh1750.getLux();

If I take readings every minute, about 1-2 of them per hour will end up with zero in lux_T1red on a ProMini system running at 8mhz (default 100khz I2C bus). When I added a counter to the loop it's clear that the do-while is ending at seemingly random times 'before' the BH1750 has had enough time to gather its next reading. It's rare, but I've seen this behavior on 3 different systems with the same code, but different hardware & BH1750 sensor modules. The sensor modules are just cheap ones from eBay, so there is a possibility of that being a factor, rather than your library (?). Anyway just passing on the info.

Hi,
Using ESP32 nodeMCU-32 board.
I cannot see in any of the examples where 'float luxFactor' is used?

It is specified in the wiki to allow for sensor calibration, however I am obviously using it wrong,
as changing the value does nothing.

I have written my code using the 'non blocking' example and below is my function, which takes a reading, increases luxFactor, prints both values and runs in a loop.

Apologies for posting here, I cannot find a way to contact you directly or a forum for your library.

void lightmeter() {
float luxFactor;
luxFactor = 0.96;
while (digitalRead(Button3) == LOW) {} // wait for button release
delay(50); // short delay for bounce
BH1750.start(); // ask sensor to take a reading

while (digitalRead(Button3) == HIGH) { // wait for button press to return from lightmeter subroutine

if (BH1750.hasValue() == true) {  // non blocking reading
  float lux = BH1750.getLux();
  Serial.print("lux: ");
  Serial.print(lux);
  BH1750.start();  // ask sensor to take a reading

  luxFactor = luxFactor + 0.01;
  if (luxFactor > 1.44) { luxFactor = 0.96; }
  Serial.print("    cal: ");
  Serial.println(luxFactor);
}

lux: 6.67 cal: 1.19
lux: 6.67 cal: 1.20
lux: 6.67 cal: 1.21
lux: 6.67 cal: 1.22
lux: 6.67 cal: 1.23
lux: 6.67 cal: 1.24
lux: 6.67 cal: 1.25
lux: 6.67 cal: 1.26
lux: 6.67 cal: 1.27
lux: 6.67 cal: 1.28
lux: 6.67 cal: 1.29
lux: 6.67 cal: 1.30
lux: 6.67 cal: 1.31
lux: 6.67 cal: 1.32
lux: 6.67 cal: 1.33
lux: 6.67 cal: 1.34
lux: 6.67 cal: 1.35
lux: 6.67 cal: 1.36
lux: 6.67 cal: 1.37
lux: 6.67 cal: 1.38
lux: 6.67 cal: 1.39
lux: 6.67 cal: 1.40
lux: 6.67 cal: 1.41
lux: 6.67 cal: 1.42
lux: 6.67 cal: 1.43
lux: 6.67 cal: 1.44
lux: 6.67 cal: 0.96

Hello @Starmbi ,

This is my code:

#include <hp_BH1750.h>                          // include the library

hp_BH1750 sensor;                               // define the sensor

void setup() {
  Serial.begin(115200);
  Serial.println("start");
  
  bool avail = sensor.begin(BH1750_TO_GROUND);  //A: set address and init sensor
  
  if (!avail) {
    Serial.println("No BH1750 sensor found!");
    while (true) {};                                        
  }
  
  Serial.println("calibrating sensor...");
  sensor.calibrateTiming();                     //B: calibrate the timings, about 855ms with a bad chip
  Serial.println("calibration finished");
  sensor.start();                               //C: start the first measurement
  Serial.println("end");
}

void loop() {
  if (sensor.hasValue()) {                      //D: most important function of this library!
    float lux = sensor.getLux();                //E: read the result
    Serial.println(lux);
    sensor.start();                             //F: start next measurement
  }

  delay(1000);
  Serial.println("waiting");
}

And it blocks at

20:11:02.892 -> entry 0x400805f0
20:11:02.993 -> start
20:11:02.993 -> calibrating sensor...

My wiring for my ESP32, and the sensor's green light is on.

• ADDR -> GND
• SDA -> pin 21 (I2C SDA) with 4.7 KOhm pull-up to 3.3V
• SCL -> pin 22 (I2C SCL) with 4.7 KOhm pull-up to 3.3V
• GND -> GND
• VIN -> 3.3V

the I2C scanner returns I2C device found at address 0x23