A few days ago my Fairphone started giving me a black screen during phone conversations. I noticed it also blacks out while having a conversation through Viber. I can’t do anything while ringing or talking, not even hang up. So when I get connected to voicemail my only option is to take out the battery to hang up. If I do get connected to someone I have to ask them to hang up after we finish the conversation, because I can’t. After that, the phone works fine again. Any clues on how to fix this, because it’s quite annoying and I can’t use my phone this way.
When you’re making a phonecall and hold the phone at your ear then the near field sensor kicks in. It takes seconds for the screen to turn to normal.
In this article you can read more about it.
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Hi Lidwien, thanks for your reply. This isn’t my issue though. I know the functioning of the sensor and that always worked fine (although the reaction time could be a bit quicker, but I got used to that). My problem however is that my screen doesn’t come back in any way during a call. It just stays black no matter how I hold the phone or which button I push. The moment I press call the screen blacks out. The only way to get out of it is when the person I’m calling hangs up (after that the screen lights up again and works fine) or if I remove the battery during the call/voicemail message.
Same issue here: I have to hope the other party hangs up…
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Not a solution, but you can configure your phone to hang up when you press the power button.
To enable this, go to settings, then to accessibility and check the option “power button ends call”.
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Thanks for the info Jerry. Like you said not the solution, but at least I can use the phone again.
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Hi,
I have the same problem. Thanks for the bypass - i always had to take out the battery if i got a mailbox or wait for the other party to hang up.
Other OS have a secret menu where you can test the near field sensor. How can i find this on my FP ?
I am using SatStat. On the second tap there is a field called distance (Edit: It says Proximity)(cm), which does not really display the distance, but indicates if the near field sensor is covered. (If it is, the indicator turns to 0).
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Never noticed, thank you. 
By the way, on my phone it is called “Proximity (cm)”, I’m using the 2.0 version of SatStat.
Bye
Installed the app and I notice that only the light intensity (lux) changes.
Proximity is and stays 0. So I guess that’s the problem, right? Is there a
way to fix this? Or at least set this manually to a higher number so I can
use other functionalities again during a call?
Mine says 1 when not covered, and turns to 0 when I cover the near field sensor. Interestingly though, it does not change back when I uncover the sensor. I haven’t experiences problems during a call.
Tested on a FP1 with Cherry 1.6.
Same configuration with me with a different result: Proximity changes to 0 if I hold something approx. 2 cms above the sensor (next to the speaker) and changes back to 1 if I lift it again.
Strange that it doesn’t work for some of us. I’d file a bug report.
As I said, this doesn’t affect calls. During a call everything works.
Which version of SatStat are you using? Mine is 2.0 (git-7e8af75).
PS.: Sometimes, after some tries, it does change back to 1 when uncovered…
Apparently a pretty ancient version 1.8. I’ll update and report back.
I’ve updated version 2.0 from F-Droid and still have same results: Proximity changes each and every time I cover and uncover the sensor.
I’ve found an app that kind of works for me. It’s still not a real solution, but at least I can use my screen again during calls. I think the app turns off the proximity meter, so my screen stays active when I call. If I do want to disable the screen during calls I have to push the on/off button of the phone to disable it, and press it again to enable it.
The app is actually meant for something else, locking and unlocking your phone with gestures. But you can turn that off in the app. The only settings I have activated are ‘Enable Proximity Unlock’ and ‘Device Admin Enable’.
https://play.google.com/store/apps/details?id=com.perfectminders.main&hl=en
Check out Sensors Sandbox (Probe available sensors) - https://f-droid.org/app/com.mustafaali.sensorssandbox.
If I select the proximity sensor, it changes immediately. So, I think the telephone-app should be revised…
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I have the same problem. For me it help when I put an headphone or speaker in the Phone. Then I get the keybord back.
I just replaced the entire display assembly on my FP1 - the old screen had broken and didn’t react to touch commands anymore. Upon opening the phone I was surprised at the amount of dust and especially tobacco crumbs (I quit smoking eight weeks ago) that had found their way into the deepest depths of the phone. Literally all components on the inside were covered. Quite amazing to see that.
Upon putting the phone back together I had a similar issue to the one you are describing above: during calls the screen would largely stay black and only intermittently turn on and then quickly off again. I figured it would have to be the proximity sensor, did a quick online search and found this topic here.
##How to clean the proximity sensor
As suggested above I installed Satstat and found that the proximity sensor indeed kept randomly turning on and off - quickly switching back and forth between 1 and 0. The only time I could get it to stay on 0 (covered) was to put my finger on the sensor field, suggesting that it might be at least partly a mechanical issue, not a software problem. I disassembled the phone again and cleaned the area around the proximity sensor in three places: 1) the sensor itself on the motherboard (CAREFUL!) 2) the little black rubber bumper piece between the display assembly and the sensor and 3) the inside of the new display assembly.
I used the following guide from ifixit.com: https://www.ifixit.com/Guide/Fairphone+Display+Assembly+Replacement/20605 – you can clearly see the little black rubber component and the inside of the display assembly which I cleaned in the first two pics in step 28.
I put it all back together a second time and now it works properly - I reckon the sensor was covered by dust or tobacco or whatever.
PS - anyone in need of a defunct display assembly for tinkering?
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