We are currently using temperature sensor and Bar100 pressure sensor. There have been problems with them not being discoverable/communicable over I2C that I have been troubleshooting the past few months. (I had a previous post about this about a month ago). Progress has been made, and it seems like the hardware on the Raspberry Pi may have been part of the problem, as was previously suggested by a BR team member. However, it does not explain everything. Recently a phase has been entered where the sensors will only show up under an i2cdetect scan if and only if the voltage supply lead is NOT connected. I can have the ground, data and clock wires connected, and the sensor addresses will show in the scan. But, as soon as the voltage supply/hot/red wire is connected, the sensors will disappear.
I have double-checked this many times. The voltage supply pin (on the raspberry Pi) is the correct voltage. Everything is plugged in correctly. I measured with a multimeter and the voltage level seems to be correct coming out of the Pi and onto the breadboard. I and the rest of the team are at a loss to explain this behavior. Does this indicate an internal hardware problem with the sensors?