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Topic: two different Sensors on I²C Bus (Read 386 times) previous topic - next topic

sunnyraven

Some question about I²C and multiple Sensors on the bus.

I will connect an RTC (with the Logger Shield from ladyada.net) and the 9DoF Sensor Stick from Sparkfun on the I²C Bus at Arduino Uno.

When booth Sensors are connected I can read only the 9DoF and not the RTC Data`s
If the 9DoF disconnected I can read the RTC Data`s

Have Some one an Idea what the problem or can`t I connect the two Sensors at one I²C Bus?

Thank you for the answers

Grumpy_Mike

Yes you should be able to have more than one sensor on a but at the same time. In fact in theory you can have 128 of them.
Are the addresses different?
Have you got two sets of pull up resistors or even no pull up resistors?

sunnyraven

Thank you Grumpy_Mike for the hint with the pull up resistors.

On the 9DoF run the Bus with 4,7K to 3.3 Volt and on the RTC with 2,2K to 5 Volt. Thats can not run.

So I have an problem what can I do? Can the DS1307 RTC run with 3,3 Volt on the I²C or have I an other chance to connect to I²C Buses with different Voltages?


Grumpy_Mike

Quote
have I an other chance to connect to I²C Buses with different Voltages?

Yes you can do that look at using a I2C level converter, it is easy enough to do:-
http://www.hagtech.com/pdf/translator.pdf

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