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Linux PinePhone has physical kill switches for its cameras, mic, data, BT, Wi-Fi

androidpolice.com

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Re: Linux PinePhone has physical kill switches for its cameras, mic, data, BT, Wi-Fi

#2

Post by m0zg »

Too bad the battery "kill switch" seems to be turned on permanently. I don't blame them - it's a hard problem to solve. Todays higher end phones go as far as to turn off parts of the chips on the fly, dynamically, on demand. But until it is solved, the device is more or less a curiosity rather than something useful in practice.

Re: Linux PinePhone has physical kill switches for its cameras, mic, data, BT, Wi-Fi

#4

Post by damip »

What are the killswitches acting on ? Are they acting only on the dedicated "enable" or "poweroff" inputs of various chips ? Are they cutting the power supply of the chips ? Are they cutting both the power and logic busses, thus isolating the target chips (at least electrically) ?

Re: Linux PinePhone has physical kill switches for its cameras, mic, data, BT, Wi-Fi

#5

Post by hawski »

damip wrote: post #4

What are the killswitches acting on ? Are they acting only on the dedicated "enable" or "poweroff" inputs of various chips ? Are they cutting the power supply of the chips ? Are they cutting both the power and logic busses, thus isolating the target chips (at least electrically) ?

From https://wiki.pine64.org/index.php/PinePhone_FAQ#What_are_the...

  1  Modem | Pulls Q1501 gate up (FET killing modem power) | "On" enables 2G/3G/4G communication and GNSS hardware, "off" disables it.
  2  WiFi / Bluetooth | Pulls up CHIP_EN | "On" enables WiFi and Bluetooth communication hardware, "off" disables it.
  3  Microphone | Breaks microphone bias voltage from the SoC | "On" enables audio input from on-board microphones (not 3.5mm jack), "off" disables it.
  4  Rear camera | Pulls up PWDN on OV5640 | "On" enables the rear camera, "off" disables it.
  5  Front camera | Pulls up PWDN on GC2145 | "On" enables the front camera, "off" disables it.
  6  Headphone | Pulls up IN2 on analog switch BCT4717ETB | "On" enables audio input and output via the 3.5mm audio jack, "off" switches the jack to hardware UART mode.

Re: Linux PinePhone has physical kill switches for its cameras, mic, data, BT, Wi-Fi

#7

Post by fsflover »

prox wrote: post #3

Is anyone usimg a linux phone? Love to hear use cases. I know about the PinePhone and the Librem, don’t know if there are others.

There are a lot of videos on Youtube, e.g. https://www.youtube.com/watch?v=bH3RbrwhNd8

Re: Linux PinePhone has physical kill switches for its cameras, mic, data, BT, Wi-Fi

#8

Post by fsflover »

m0zg wrote: post #2

Too bad the battery "kill switch" seems to be turned on permanently. I don't blame them - it's a hard problem to solve. Todays higher end phones go as far as to turn off parts of the chips on the fly, dynamically, on demand. But until it is solved, the device is more or less a curiosity rather than something useful in practice.

Why do you need it? You can simply remove the battery (without any tools).

Re: Linux PinePhone has physical kill switches for its cameras, mic, data, BT, Wi-Fi

#9

Post by fsflover »

damip wrote: post #4

What are the killswitches acting on ? Are they acting only on the dedicated "enable" or "poweroff" inputs of various chips ? Are they cutting the power supply of the chips ? Are they cutting both the power and logic busses, thus isolating the target chips (at least electrically) ?

One can check the schematics: http://files.pine64.org/doc/PinePhone/PinePhone%20v1.2a%20Re...

Re: Linux PinePhone has physical kill switches for its cameras, mic, data, BT, Wi-Fi

#10

Post by KMag »

hawski wrote: post #5
damip wrote: post #4

What are the killswitches acting on ? Are they acting only on the dedicated "enable" or "poweroff" inputs of various chips ? Are they cutting the power supply of the chips ? Are they cutting both the power and logic busses, thus isolating the target chips (at least electrically) ?

From https://wiki.pine64.org/index.php/PinePhone_FAQ#What_are_the... 1 Modem | Pulls Q1501 gate up (FET killing modem power) | "On" enables 2G/3G/4G communication and GNSS hardware, "off" disables it. 2 WiFi / Bluetooth | Pulls up CHIP_EN | "On" enables WiFi and Bluetooth communication hardware, "off" disables it. 3 Microphone | Breaks microphone bias voltage from the SoC | "On" enables audio input from on-board micr…

With the microphone bias floating, what prevents some digital signal processing form recovering faint and fuzzy audio? I'm sure the microphone loses at least several dB of gain with the bias floating, but isn't it much safer to either disconnect the bias and tie it to ground, or else pull up/down the the digital output of the ADC?

I understand that with the bias floating, the microphone output will be a combination of radio and quantum thermal noise, but won't that noise still be slightly modulated by the microphone? Or is it that the noise being modulated will be below detectable by the ADC and the digital output will always be exactly 0?

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