# Speaker PHAT invisible on i2c

**URL:** <https://forums.pimoroni.com/t/speaker-phat-invisible-on-i2c/7035>\
**Category:** Support\
**Created:** [January 29, 2018, 4:10pm UTC](https://forums.pimoroni.com/t/speaker-phat-invisible-on-i2c/7035 "2018-01-29T16:10:07Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![rcw88](https://avatars.discourse-cdn.com/v4/letter/r/aca169/32.png) [@rcw88](https://forums.pimoroni.com/u/rcw88)\
**Post date:** [January 29, 2018, 4:10pm UTC](https://forums.pimoroni.com/t/speaker-phat-invisible-on-i2c/7035/1 "2018-01-29T16:10:07Z")

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I’m building a deskside clock radio because my ancient one is dying - I have several I2C devices running through a 3v/5v adafruit level convertor because the Adafruit display and Lux sensor run on 5V this means I cannot just plug the Speaker PHAT onto the Pi Zero with a 40way header…

The Lux sensor and Adafruit display respond to i2cdetect -y 1, the speakerphat doesn’t, I’ve tried speakerphat on its own and still no joy. I2C still works on the Pi so there’s no problem with anything other than speakerphat :-(.

Any ideas? - its not a disaster, I don’t want to use the VU meters but I’d like the i2c interface to respond [N.B. there’s no address clash]

P.S, Stretch, full GUI, on a Pi Zero… but that’s just for prototyping…

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**Author:** ![gadgetoid](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/gadgetoid/32/13_2.png) [@gadgetoid](https://forums.pimoroni.com/u/gadgetoid)\
**Post date:** [January 29, 2018, 6:27pm UTC](https://forums.pimoroni.com/t/speaker-phat-invisible-on-i2c/7035/2 "2018-01-29T18:27:32Z")

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This is normal. Speaker pHAT uses an SN3218 which is write-only, so `i2cdetect -y 1` wont “see” it. You need to use, IIRC, `i2cdetect -q 1` which attempts a write to all addresses.

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**Author:** ![rcw88](https://avatars.discourse-cdn.com/v4/letter/r/aca169/32.png) [@rcw88](https://forums.pimoroni.com/u/rcw88)\
**Post date:** [January 30, 2018, 8:54am UTC](https://forums.pimoroni.com/t/speaker-phat-invisible-on-i2c/7035/3 "2018-01-30T08:54:45Z")

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Hi there, many thanks - that command isn’t one I was aware of - but the three devices now appear. I’ll put that in my build notes… Easy to miss that the device is write only - interestingly the other devices also appear with a write command.

Can get on with the case design and final cabling, waiting for an Adafruit perma-proto hat [without EEPROM].

Thanks for your help, I was thinking it was the wiring and I’d somehow blown something. But its all Good!.

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**Author:** ![gadgetoid](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/gadgetoid/32/13_2.png) [@gadgetoid](https://forums.pimoroni.com/u/gadgetoid)\
**Post date:** [January 30, 2018, 9:22am UTC](https://forums.pimoroni.com/t/speaker-phat-invisible-on-i2c/7035/4 "2018-01-30T09:22:51Z")

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Yeah it’s caught me out on numerous occasions, despite me _knowing_ that it’s write-only! Glad you’re sorted.