Proximity sensor goes crazy in sunlight (WhatsApp, Signal, Facebook Messenger, Stock Dialer, WaveUp)


I came across a curious bug today. I use WaveUp to turn the screen on/off using the proximity sensor. Today when I was on a walk, the screen just kept turning on and off like crazy. I noticed that it happens only when the sun shines directly on the phone. If I am correct, the proximity sensor uses IR light to detect objects. So I suspect it’s badly calibrated, but unfortunately (as far as I know) there is no tool to recalibrate it. Note that it works flawlessly inside and outside in the shade or in cloudy weather.

To be fair, I use an unofficial screen protector and altough I made sure that it doesn’t cover the proximity sensor nor the light sensor, the edge of the protector is directly next to it. (I cannot move it any lower.) Could this behavior be caused by some reflection from the edge?

My guess is it’s just a bad calibration. But before I contact support about this, I have to ask, does this issue affect anyone else?

I don’t think that problem is FP4 specific, I have the same behaviour with my Nexus 4 (haven’t used the FP4 enough in outdoor settings to notice it there). Direct sunlight or the refraction from small drops of water will sometimes make WaveUp go crazy.

I fixed it by disabling WaveUp when cycling / hiking. Not the best solution, I know :smirk:

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Thank you, I didn’t know about this. I’ve actually never used WaveUp on any other phone. My previous phone was Moto Z2 Play, which had a similar feature out of the box (Moto Peek Display), but it used ultrasound and worked flawlessly in basically any condition. I really miss that. :smiley:

Well, stupid problems require stupid solutions. Fortunately, WaveUp supports enabling/disabling the service using broadcasts ( and So I just created a small Automate script, which disables it when the ambient light is over 10,000 lx. :smiley:


Automatically turning it off when it’s too bright, brilliant :smiley:

I used Easer and NFC tags to do it manually (and not so elegantly) :see_no_evil:

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Hey there, I have noticed this behaviour of my Fairphone4 too, especially in good weather with a low sun, like there is atm in Germany. I don’t think this is normal, my old Huawei P9 lite never did something like this. It goes as far as that in certain lighting situations, the phone becomes unusable. If you are passenger in a car and the nearby trees, houses, bridges cause a rapid change between shadows and sunlight, sometimes the phone can’t keep up and straight up locks the screen and takes “a pause” (like 10 seconds) before it will respond again. This even happens when walking through a forest. This only happens in applications where the proximity sensor is used, of course, like making phone calls, using threema and WhatsApp. Listening to a voice message while casually walking through the forest in nice weather? Not possible, it will be interrupted 30 times until the phone freezes completely. Is there something i could do, maybe thorugh developer tools, to change the proximity sensor behaviour? Thanks for any ideas!


Hello and welcome to the forum. Thank you for your message. I’ve already contacted support and I’m waiting for their answer. I really hope it’s just a matter of calibration. But please make sure to report it too (#contactsupport). The more people tell them about this, the more likely it will be fixed.


Just to clarify the situation: Are you also using WaveUp? Or is your FP4 behaving like that without this App?

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Sorry, I mainly replied under this post, because the title did fit well. But no, I don’t use this app. It’s just the standard behaviour on my Fairphone I guess. I just loaded system patch FP3S.A.0103, but that is literally moments ago, so I can’t say if that fixes anything.

Well, in my case it’s mainly WaveUp, but basically anything that turns off the screen based on proximity is affected, such as phone calls or audio recordings in WhatsApp and Facebook Messenger. So this is just a general problem with the proximity sensor on direct sunlight.


But without WaveUp, the screen would never turn on based on signals of the proximity sensor.

It would if you are making a phone call.
Holding the phone to your ear will disable the screen and removing it from your ear will enable the screen again. Apparently WhatsApp also uses that for audio recordings.


Just adding a Reddit thread that also reports this:


Update from support:

Concerning the issue with the proximity sensor, we are indeed aware of this as well and have started investigations.

Let’s hope it will be just a matter of calibration.


I think so. I’m calling indoors with no direct sunlight or artificial light. But sometimes the screen goes on while I keep the phone to my ear. Using official screen protector.

If I understand this problem correctly it’s mostly a WaveUp issue that’s also present on other phones? Sounds like this issue is then more related to WaveUp. There is an issue indeed with the sensor while calling, this issue is also included in the known issues wiki.

I suggest the following. Since this issue in this topic is about WaveUp, I would like to remove it from the known issues list and keep the topic on the wiki about the proximity sensor while calling.

That topic is more related to something Fairphone can fix. In case they improve the sensors and WaveUp works better as a result of that, then that’s a win.

But now there are 2 topics about the same issue(?), while this topic seems to be more of a 3rd party app issue. Dropping that one keeps the list more organized without duplicates or app isues beyond the scope of FP. Unless of course FP really acknowledged this is a FP issue with WaveUp. But when I read the support response it seems they are working on a general improvement of the sensors.

What do you think?

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I think its confirmed its not Wave Up (alone)


It’s a proximity sensor issue, not an app issue. On direct sunlight it occasionally (for a brief moment) thinks it’s covered even though that’s not the case. In other words, it sometimes falsely reports 0 cm distance.

I’m not sure how much these two issues are related. In fact, the opposite problem occurs when making a phone call. The proximity sensor reports 5 cm, even though it should report 0 cm.


Since a few people agree with you I’ll leave it as is. There is indeed a sensor issue which needs to be resolved. But I’m not sure if we need 2 of them in the list, of which one is classified as “Medium impact - I can only partially use the phone”, while it seems to be only an issue when using WaveUp. Since these classifications should reflect the impact on the average user, I don’t think a medium impact is really in proportion. Since most people probably don’t use WaveUp.

The sensor issue while calling doesn’t happen very often to me either. I have daily calls for work. So last suggestion would then to lower the impact from medium to low impact. To make sure these issues carry a proportional weight.

Not really. You are also basically unable to play WhatsApp or Facebook Messenger audio messages on direct sunlight, because the screen flickers and playback stops. (This is not caused by WaveUp. Those apps themselves use proximity sensor for cases when you hold the phone to your ear.) You could argue that it’s not a medium impact issue (I’m willing to change it to low impact), but it’s definitely not only WaveUp.


Got it, in that case I would suggest the following (final one) :nerd_face:

I’ll update this topic title to include a few most used apps, such as WhatsApp and Facebook Messenger, Stock Dialer, along with WaveUp. And then I’ll remove the other topic which only mentions the dialer from the wiki list.

That way it has the weight to justify a medium impact and we keep the list free of redundant topics.