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Morning Folks,

I'm a new Pi programmer attempting to hookup multiple TMP102 sensors over I2C. I started this journey with this http://www.instructables.com/id/Raspberry-Pi-Temperature-Logger/?ALLSTEPS instructable, and I have one sensor at a time reading just fine.

Unfortunately it looks like both sensors I'm trying to hookup are registered to address 0x48. I've tried changing the address with the code OP posted here https://www.raspberrypi.org/forums/viewtopic.php?f=44&t=63419 with no luck. It doesn't seem like the sensor wants to change addresses.

Has anyone here attempted to connect two of these to a Pi and could point me in the right direction? I'm starting to think it's not possible to connect both over i2c.

Thanks.

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TMP102 datasheet Tabel 4

DEVICE TWO-WIRE ADDRESS    A0 PIN CONNECTION
1001000 (0x48)             Ground
1001001 (0x49)             V+
1001010 (0x4A)             SDA
1001011 (0x4B)             SCL

You assign each device a unique bus address by connecting pin A0 to one of the other pins. I have added the hex address of the device to the table.

You don't configure the address in software, you configure the address with hardware.

The linked raspberrypi.org post was changing the I2C address of a SRF02 sonar ranger.

Don't use instructions for one piece of hardware on another piece of hardware unless you know they are compatible. It's like using the tuning details from a motorcycle manual in an attempt to fix a ship.

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  • Thanks a bunch! I stared at that Table for a while last night with no revelations. Just to be clear, if i hooked a jumper wire between ADD0 and SDA it would set the address to 0x4A? – Bob Herman Mar 17 '17 at 14:46
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    @BobHerman That is my interpretation of the table. You may find the module you bought to "break-out" the TMP106 already has jumpers set on board though. The tutorial you linked to shows a photo of a break-out board where a solder blob is added to jumper ADD0 to ground. You would need to undo any such mods already made. – joan Mar 17 '17 at 14:59
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For anyone coming back to this via google this is the full solution:

The ADD0 pin is used to change the address of the TMP102. If you’re using multiple TMP102s or another device that uses that address, you’ll want to use this pin to change the address. The default address is 0x48. You can change the address by cutting the ADD0 jumper on the back of the board and connecting an external jumper wire to the following pins:

VCC → 0x49

SDA → 0x4A

SCL → 0x4B

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