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Topic: May indicate a problem with BMP085 + RTC with I2C and sending data to COSM.COM (Read 1 time) previous topic - next topic

icnmfabro

after several tests by sending data to the platform COSM.COM I discovered a possible problem with the two sensors connected in I2C namely: 1 RTC + 1 BMP085 causing a block after several hours of arduino.
on run the test ... code done with random numbers seems to work ... cosm respond and forward the data it locks... so I connected one by one sensor, it seems that also works with the DHT22 sensor connected ... but it crashes (with different timing) when I insert the RTC and the barometer BMP085 connected to the i2c. sensors are also connected to a logic level converter sparkun so in theory should not give big problems ... I groped to turn off after wire.begin () pull up the interior door SCL and SDA, but you is one thing to do with a logic level converter connected between the two sensors (RTC 5V, 3.3V BMP085)?

I hope I can give you an idea of how to solve the problem ...

Grumpy_Mike

What dose this mean?
Quote
but you is one thing to do with a logic level converter connected between the two sensors

Have you got an external pull up resistor? I would use 4K7.

icnmfabro

I turned off the internal pullup SCL and SDA (for I2C) of arduino with the commands:

     / / Join i2c bus (I2Cdev library does not do this automatically)
     Wire.begin ();
     digitalWrite (SDA, 0);
     digitalWrite (SCL, 0);

I put pullup resistor in both RTC and BMP085 or only BMP085?
10k resistors that are located in the converter logic levels of SparkFun not perform the work of the external pullup for each device?

let me know. Thank you.

Grumpy_Mike

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I turned off the internal pullup SCL and SDA (for I2C) of arduino

There is no need to do this. The internal pull up resistors are quite high and so they don't make much of an impact.

You only need one set of pull up resistors of 4K7 for all your devices.

Read again the information on the SparkFun level converter, people seem to wire this up wrong.
Is it a bi-directional level converter, some SparkFun converters are not. A link would be good.

icnmfabro

ok rehabilitated the internal pullup on SCL and SDA, insert the resistance of each device, then let you know ...
Do you think the project designed with fritzing the connection to the devices and the Sparkfun converter correct?

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