[solved, lesson learned] Do these libraries conflict with I2C?

Projects General Guidance
1

I've got a project that logs data to ThingSpeak from a range of sensors. The latest sensor I added was a BH1750FVI digital I2C light intensity sensor. It worked on a bare Mega 2560, but does not work in the data logger Mega loaded with sensors. It returns '54612 lux' despite changes to illumination. I'm suspicious that conflicts between the libraries are at fault. What libraries could interact with the I2C communication to the light sensor? It is the only I2C sensor connected. Any ideas? The libraries included are listed below:

#include <Wire.h>      //LUX Light Sensor
#include <BH1750FVI.h> //LUX Light Sensor

#include <SPI.h>     // W5100 Ethernet Board
#include <Ethernet.h>// W5100 Ethernet Board

#include <OneWire.h>          //Dallas 1 wire
#include <DallasTemperature.h>//Dallas 1 wire

#include <dht.h>   //DHT22 Sensor

#include <FreqMeasure.h>  //Flow Meter, Hall Sensor
#include <FreqMeasure2.h> //Flow Meter, Hall Sensor
2

The answer to my problem was that I had a stack of shields three high, with short pin headers in-between as spacers. Some were making contact, and some weren't. When it's not working - get the voltmeter out and check continuity!

3

Yep, lesson learned :slight_smile:

Rob