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I am curious if it is possible to change the 3.5mm jack output on the raspberry pi to use it to charge a jawbone up fitness tracker?

Ghanima
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avk
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  • It's a headphone jack. Is your device normally charged from a headphone jack? – joan Apr 19 '15 at 10:05
  • yes, it is normally charged from a headphone jack. This is what is normally looks like https://jawbone.com/kb/articles/406.html – avk Apr 19 '15 at 10:27

1 Answers1

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No; The raspberrypi headphone jack (0.3mW, 1V) will not output enough watts for the jawbone (2W?, 5v? likely set to max out USB).

You can skip the raspberrypi and just use the USB power supply directly. If you have lost your headphone to USB adapter you can (assuming the adapter is only for shape) desolder a headphone jack from a raspberrypi but then your pi would be limited to HDMI audio.

user1133275
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  • Desolder the jack from the Pi? Really? Why not just buy one for half a dollar instead of potentially ruining a $35 system? – Ghanima Apr 19 '15 at 16:08
  • Yah well that's why I started with 'No' and only mentioned the other option as a "technicaly you could' but it would be silly under most conditions. – user1133275 Apr 19 '15 at 16:13
  • Okay, that makes sense. I can wait for the cable to deliver then. was thinking if there was a better way to get it done. BTW, where did you find out that the required output was 5v ? – avk Apr 19 '15 at 16:27
  • @user1133275 why would the pi not output 5v 1A over the headphone jack, i am curious. – avk Apr 19 '15 at 16:36
  • @avk The rPi is designed to plug into an amp, so spending the extra to make it able to drive big speakers (or charge stuff over the audio jack) was an unjustifiable cost for most of the target market. – user1133275 Apr 19 '15 at 16:52
  • @avk, on a side note. The Pi itself is powered via its USB plug and according to raspberrypi.org it consumes between 700-1000mA (Type B). Neither the power supplies typically used nor the USB plug powering the Pi would support another additional 1A. – Ghanima Apr 19 '15 at 20:25