BMP180 barometric sensor (I2C) not detected.

Hello all,

I've bought myself a BMP180 sensor exactly like shown here :

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The problem is that my RPi, using "i2cdetect -y 1" doesn't seem to detect it. The RTC connected at the same time does show up though (meaning: I2C is enabled and working).

I've tried to power the BMP board thru both the "3.3" as well as the "vcc" connections (with 3.3 volts) (not at the same time), checked the electrical connections from the boards header to the other side of the cable, tried with and without the RTC and even swapped "sdl" and "sda" to see if that would make a change. Nothing worked. :-(

Any idea what might be going on, or should I consider it DOA ?

Regards, Rudy Wieser

Reply to
R.Wieser
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Rudy, I have some notes here:

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but I don't think they'll help (because your i2c is working). There's a newer version BMP/BME 280 if you decide to replace.

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Cheers, 
David 
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Reply to
David Taylor

David,

Thanks. Stored for later use.

:-) I bought that sensor just a week or so ago, just to see what it does. Currently I'm just trying to figure out if I should return it to the store, or that I forgot a step somewhere (I've read that it can sometimes be finicky).

Regards, Rudy Wieser

Reply to
R.Wieser

If as you say the i2c is enabled and working on the RTC then it strongly sounds as though the module is DOA. The wiring is not exactly complicated and doesn't seem particularly sensitive to cable lengths or types. The one extra check I would suggest is a quick check with a new unmodified OS install to just check that any software loaded as part of the RTC or otherwise hasn't interfered with normal operation of the i2c bus.

I got these:

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Hello all,

Reply to
notvalid

notvalid,

Yup.

Indeed. The only problem I had was how to supply 3.3 volts to mine (as I have two candidate pins for that).

:-) I did not install any such software. I just used some Python to read the RTC and than shelled a command to set the clock with it, executed on startup. In other words, AFAICS nothing was/is using the I2C bus.

But to make sure nothing of the kind would be happening I also tried, instead of the pressure sensor, an MCP9808 temperature sensor. It was detected without a problem.

The only thing that that keeps nagging me is that the breakout board perhaps never was designed to accept power on the "3.3" pin, and that something got destroyed when I did (later on changing it by applying 5 volts to the "vcc" pin didn't help).

Regards, Rudy Wieser

P.s. Yesterday I emailed the webstore with my findings, and they had no problem with sending another. They didn't even mention anything about returning the old one.

Reply to
R.Wieser

I received it yesterday and connected it today using 5 volt on the "vcc" pinc (just wanted to make sure), and it was detected without any kind of problem. After that I switched to providing 3.3 volt to the "3.3" pin (bypassing the voltage regulator), and it again detected. Phew. I did not blow anything up after all. :-)

After that I took a look at the old sensor using a magnifier to see if I could perhaps spot a mis-solder. Only than I noticed that it had, somewhere between now and two days back, lost its cap (with the tiny hole in it) ... I did not bother looking any further, and tossed it.

Regards, Rudy Wieser

Reply to
R.Wieser

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