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TSL2561
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TSL2561

by chellia on Thu May 05, 2016 9:31 am

Hi,

I want to connect three TSL2561 sensors to the same I2C bus. I know that I can assign to each sensor a different address by connecting the address pin either to VCC or GND or keeping it unconnected. My question is regarding the pullup resistors set. What I know is that each TSL2561 breakout board contains a pullup resistors set. If I connect 3 TSL2561 sensors to the same I2C bus only one set of pullup resistors should be used on that I2C bus. This means that I need to remove the pullup resistors in 2 of the TSL2561 that I want to connect and keep the pullup resistor in only one TSL2561 (reminder I have 3 TSL2561 connected on the same I2C bus). Is my understanding correct? Do I need to remove 2 pullup resistors set? How can I remove these pullup resistors without damaging the breakout board?

chellia
 
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Re: TSL2561

by adafruit_support_bill on Thu May 05, 2016 9:54 am

only one set of pullup resistors should be used on that I2C bus.

This is not necessarily true.

The pullups used on these sensors are 10Kohms which is a relatively 'weak' pullup. 3 sets of 10K pullups on the same bus is only 3.3K and will not cause a problem. You might run into problem when you have 4 or more, In that case the extra pullups can be removed.

adafruit_support_bill
 
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Please be positive and constructive with your questions and comments.