Dimming PX6 MCPE Display - Android Head-Units

Hi guys,
So I just recently got a Dasaita PX6 MCPE for my 2014 Honda Accord. The screen is so bright its insane, my dashboard can't even match it at the brightest night setting. Daytime it is good, but I can't dim the display enough for night use. I've contacted Dasaita about it and there response was "put window tint on your radio". The problem is it wouldn't be bright enough for day with window tint on it :/
I'm wondering if anyone has had any success with these units to make the screen brightness at night dimmer. I've tried using apps like Lux but my display is still putting out too much light. I live in the country and am on very dark roads, its tolerable when I hit the city. Right now I have to keep the screen off while driving on my road.
Now naturally, I'm not just posting "how do you fix it": instead I'd like to share what I've done so far and see if anyone else has any ideas:
1) Finding the PWM device in the kernel. Using the ADB root shell I've looked around to find some PWM devices. I figured they must be controlling the display brightness using one of the RK3399 PWM outputs. After a lot of searching, I found a PWM device which somewhere had been labelled as Backlight:
```
$ more pwm
platform/ff420030.pwm, 1 PWM device
pwm-0 (vdd-log ): requested enabled period: 24997 ns duty: 4246 ns polarity: inverse
platform/ff420010.pwm, 1 PWM device
pwm-0 (backlight ): requested enabled period: 24997 ns duty: 0 ns polarity: normal
```
`ff420010.pwm`
I tried sending a new brightness to the device by editing the power file in `/sys/devices/platform/ff420010.pwm/pwm/pwmchip0/power` using `echo "250" > power` but it didn't change anything. Perhaps I'm not editing this file right, but in my experiences in the past this is usually how screen brightness is controlled, via PWM driven off the main processor (for embedded applications of course).
If we can find how this device is driven, (wether its the MCU or CPU) I'm confident we can dim the display. I think the frequency for the PWM is too high, so even though the duty cycle may only be 5%, we get very little range as our eyes are compensating for it. I contacted Dasaita with this information and theory behind it but they don't care (they already have my money of course). This is something I've observed with LED's in the past when I set the PWM frequency too high.
2) My next plan was to modify the actual device driver circuit and add a RC filter so when the device was being given a shorter duty cycle it would start to ground out some of the power, effectively adding more range, as when the duty cycle neared 100% it would be DC and the circuit would no longer pass any power to ground. At this point I was still under the assumption that the backlight was LED, as it is 2020 of course. Upon further inspection I realized that it is not driven by LED, but is a CCFL driven display. I unplugged the harness for the backlight and voltages were above 30v, and you could hear the circuit trying to ignite the bulb. To be extra sure, the measured impedance across the terminals was immeasurable with my equipment. I have very little experience with this kind of florescent so I started messing around and was able to get the device to dim by putting a resistor inline, but the driver was struggling (you could hear it hissing) and I lost all range on the devices dimmer.
My theory is that the display is actually running off the MCU and not from the CPU... even though I can't prove it and it doesn't make sense to do it like that. Its a CCFL so it can't be easily dimmed with hardware modifications that I can do.
If anyone has any input on how to make the display dimmer it would be super appreciated. Normally I would find another solution but this is the only radio I can find for my car that isn't god awful. I'm pretty new to Android, but come from a Linux and embedded systems background so perhaps there is something I'm missing?

Have to tried something a bit simpler like using darker colours on your themes and apps? Most nav apps for example have "day" themes and "night" themes which makes a HUGE difference in glare and brightness.

Yes I have tried that, even with a screen filter app like lux the screen is still too bright. The problem is the display can only limit so much light itself. It just glows so bright.

Good write up and attempts to solve
Assume your device is an MTCD device and thread heading is a typo? (The MCU starts with MTCD, MTCE, or MTCP. If so, head over to the MTCD forums and also take a look at the schematics for the MTCD in my signature.

What you should try:
Connect via ADB (Laptop/PC and unit in the same WiFi network) to your unit and send this command to the unit:
Code:
adb shell settings put system screen_brightness 0
and afterwards
Code:
adb shell settings put system screen_brightness 255
If that works, you should think about using Tasker to get the unit to night view.
...and if it works, there is an alternative to Tasker: Just use the Fcc Car Launcher. There is a widget to get this done dependent on sunrise and sunset.

marchnz said:
Good write up and attempts to solve
Assume your device is an MTCD device and thread heading is a typo? (The MCU starts with MTCD, MTCE, or MTCP. If so, head over to the MTCD forums and also take a look at the schematics for the MTCD in my signature.
Click to expand...
Click to collapse
Haha yes you are right it is a typo. It was a long day. It is a MTCE MCU. I’ll see what I can dig up, I find it really difficult to navigate XDA and find anything lol

rigattoni said:
What you should try:
Connect via ADB (Laptop/PC and unit in the same WiFi network) to your unit and send this command to the unit:
Code:
adb shell settings put system screen_brightness 0
and afterwards
Code:
adb shell settings put system screen_brightness 255
If that works, you should think about using Tasker to get the unit to night view.
...and if it works, there is an alternative to Tasker: Just use the Fcc Car Launcher. There is a widget to get this done dependent on sunrise and sunset.
Click to expand...
Click to collapse
Good point! I did try actually to set the screen brightness using the settings command in ADB root mode but got no response on the screen which is why I believe it’s controlled by the MCU and not android. The brightness dials on the system are just addons. I didn’t write this part up another one of my mistakes lol
I have used a widget for that too, my screen does change based on brightness automatically (day/night mode) with my headlights fortunately but it doesn’t dim enough is all.

Related

Athena, Automatic Backlight Adjustment?

I wonder if somebody can give a solution of automatic backlight adjusting.
I think as a phone Athena need to be bright enough to use outdoor as well as in house. But it is a pity that the screen looks poor outdoor if the environment is already light.
My idea is to check the brightness via its built-in camera and adjust the backlight setting automatically. But it is again a pity that I am not able to develop on WM...
Can anybody give a solution? I would appreciate very much!!!
I have this feature on my Dell D620 notebook (dim sensor) and can tell, it's not significantly useful - at least I can see no difference, since the display itself is too dark for regular outdoor use.
Regarding your solution: I think the permanent camera-use would consume quite some power, wouldn't it? So the costs would be a faster leeching of the battery while the benefits are to automate a rather simple backlight-slider changing...
Any good? Camera+program vs. eye+hand?
will_990 said:
I have this feature on my Dell D620 notebook (dim sensor) and can tell, it's not significantly useful - at least I can see no difference, since the display itself is too dark for regular outdoor use.
Regarding your solution: I think the permanent camera-use would consume quite some power, wouldn't it? So the costs would be a faster leeching of the battery while the benefits are to automate a rather simple backlight-slider changing...
Click to expand...
Click to collapse
Hello will_990,
I totally disagree with you. Form view points of benfit and battery.
I agree with you that the display itself is too dark. It is dark even if I manually turn it to max when I stay in sunlight. But won't software help a little bit? For me at least this will enable me to dail. Then the question is how to make a dail faster.
I do not see any clue it will drain larger power. If I move from a light place to a dark place, then the reduced backlight can then save some power. In addition, the camera does not have to stay on and keep acquiring brightness all the time. The use case could be:
1. User activate on screen.
2. Due to the event camera is on and light is acquired.
3. Software caculate brightness and suitable backlight.
4. The program set backlight and switch off the camera.
You have to check if a while of camera-on consumes more or lighting backlight high does. Assume that P1 is camera power and P2 is backlight power. t1 is calculation time and t3 is manual adjust delay. t2 is the duration you use it then. I expect
(P1+P2)*t1<(P2-P2')*t2.
Certainly, you can use your finger energy to adjust and thus save battery. Then P1=0 but P2*t3 is existing yet. Especially, in case you hold a device already dark, you have difficulty to find the slider so t3 becomes a consuming factor. I expect optimally even
(P1+P2)*t1<P2*t3.
I still looking for solutions...
Your opinion is well founded, however, in my opinion it is lacking at a certain point: I simply don't think that (P1+P2)*t1<P2*t3 could ever become true, unless you'd spend a really long time in changing the slider - or calculation time (and therefor CPU power consumption) would be set rather low...
I have to admit, though, that I don't know the variables' true values, therefor I can't verify or falsify your equations.
Anyway, it would certainly be interesting to test it, google is somewhat lacking on this topic.
Suppose a Case
The later equation deduces to
P1/P2 < t3/t1 - 1.
The battery is 2200mAh. I assume it lasts 3 hours with simple taping operation. So I suppose then 733mA is drawing normally without camera. Suppose the camera(the upper camera) boost the current double, addition 733mA, and calculation time is 10 seconds, and if you spend more than 20 seconds on handling the setting, you make it true.
Nevertheless I have to say, the number is just my estimation.
Even if the later one is false the feature is still attractive.
Looking for somebody to go on with this idea...
Could anybody to go on with this idea?

Beware of the Brightness Of Death

Hi all,
On a number of occasions, I've used Market apps to control the screen brightness, either manually (like a brightness widget) or scheduled (using Timeriffic - a great tool for automatic profile changes throughout the day).
Apparently, these apps are not aware of the correct minimum brightness supported by the Leo, making it too easy to go too low, which essentially disables the display completely.
Touch still works, so if I'm lucky enough to remember the location of the widget/slider/controls, I may be able to turn brightness back up to a "sane" level.
For example, Timeriffic turns the screen off with a brightness level of 10% - 15% is the lowest working setting.
If I'm unable to fix it this way, I'm basically forced to reset. The problem is that Android *remembers* this setting after a reboot, and reapplies it just when the device is vibrated slightly at the "Android" logo animation. Thus, with a black screen, it is impossible for me to unlock the SIM, hard to unlock the screen lock, and virtually impossible to correct the brightness setting. I need to remove my data.img ("hard resetting" Android) and restore what I can from backups.
The problem also seems to occur with the standard screen dimming which occurs at about half time before the "screen off" setting. I can see the display start to dim, then it suddeny turns off. In this case, however, Android of course reverts to normal brightness at the touch of the screen or press of a button.
On a related note, I have experienced (like right now) that brightness range used by Android is much dimmer then normal. That is, using the regular brightness slider in Settings, I can only vary between almost invisible (min) and quite dim (max). Curiously, in this situation, the display can get *much* dimmer than normal, without becoming disabled.
Any ideas on these issues would be most welcome!
Workarounds found later in this thread:
- Shine a bright light on the screen - the graphics are still there if you look really hard. It's not a joke!
- Use Screencast in Droid Explorer to "remote control" your Android
- adb shell "echo 255 >/sys/class/leds/lcd-backlight/brightness"
ugumba said:
Hi all,
On a number of occasions, I've used Market apps to control the screen brightness, either manually (like a brightness widget) or scheduled (using Timeriffic - a great tool for automatic profile changes throughout the day).
Apparently, these apps are not aware of the correct minimum brightness supported by the Leo, making it too easy to go too low, which essentially disables the display completely.
Touch still works, so if I'm lucky enough to remember the location of the widget/slider/controls, I may be able to turn brightness back up to a "sane" level.
For example, Timeriffic turns the screen off with a brightness level of 10% - 15% is the lowest working setting.
If I'm unable to fix it this way, I'm basically forced to reset. The problem is that Android *remembers* this setting after a reboot, and reapplies it just when the device is vibrated slightly at the "Android" logo animation. Thus, with a black screen, it is impossible for me to unlock the SIM, hard to unlock the screen lock, and virtually impossible to correct the brightness setting. I need to remove my data.img ("hard resetting" Android) and restore what I can from backups.
The problem also seems to occur with the standard screen dimming which occurs at about half time before the "screen off" setting. I can see the display start to dim, then it suddeny turns off. In this case, however, Android of course reverts to normal brightness at the touch of the screen or press of a button.
On a related note, I have experienced (like right now) that brightness range used by Android is much dimmer then normal. That is, using the regular brightness slider in Settings, I can only vary between almost invisible (min) and quite dim (max). Curiously, in this situation, the display can get *much* dimmer than normal, without becoming disabled.
Any ideas on these issues would be most welcome!
Click to expand...
Click to collapse
I don't know these app(s) but if they are writing their settings and configured values into a ini or settings file, than you might be able to connect via adb and change the setting by this way.
With tools like Droidexplorer or ADB magic, browsing through the files should be very comfortable and you might find the correct file.
this happens on regular android devices ...i have a couple of them
thatruth132 said:
this happens on regular android devices ...i have a couple of them
Click to expand...
Click to collapse
What happens? That brightness is set too low, essentially disabling the screen, so you're forced to hard reset or perform some root magic? How do you cope with it? Or does it happen that the permitted brightness range is just dimmer than usual?
Btw, until there is no light-sensor support in kernel, you can't use such apps for the brightness
Stills a good advice
I have had the same issue with the brightness range being too low. The max brightness is really dim and the colors don't seem right. That may just be the dimming effect though. If I restart the phone it seems to take care of this. I have not had the screen go below the minimum level and turn off though.
is there a fix for this. i just experienced this problem
I experienced the same with Multicon widgets.. had to delete Android and start over
somebully said:
I experienced the same with Multicon widgets.. had to delete Android and start over
Click to expand...
Click to collapse
Oh wow, not good at all, crap...
so that means if i do that i'll lose everything huh?
Theres no way to restore the factory brightness or factory settings for the android?
aznsHD2 said:
Oh wow, not good at all, crap...
so that means if i do that i'll lose everything huh?
Theres no way to restore the factory brightness or factory settings for the android?
Click to expand...
Click to collapse
As long as you have a working WinMo it should be possible to edit the values of brightness, but I have no idea where this information is stored.
Deleting Android folder and unzipping again is esentially restoring to factory settings.
yea this happens to me all the time, its a *****. it cuts off at exactly 12% for me. what i do is have aldiko(a book reader) on the home screen. if i click on it and open a book i can just swipe on the left side of the screen to adjust brightness. since i know that its on the home screeen on the right side middle, i can usually find my way back to it.
somebully said:
As long as you have a working WinMo it should be possible to edit the values of brightness, but I have no idea where this information is stored.
Deleting Android folder and unzipping again is esentially restoring to factory settings.
Click to expand...
Click to collapse
which means that i'll lose everything such as data correct? new contacts etc. msgs...
any thing on this... isnt their a file in the android folder that i could maybe replace to restore to factory settings.
and could someone post a screen shot of their phone so i know where the numbers for the pin code lockscreen. tryin to get past that, then i can adjust my brightness
LOL I experienced it one time. And I must delete data.img to restore the phone. After this, I don't use any brightness tools (except ones already in the Android build).
If anyone have solution, please point us
Well i was able to get my screen back to normal. lol.
I didnt delete the data.img, i simply copied it and then removed it, started a fresh install, and then just marked on my screen where the numbers were, turned it off, put the old data.img back. Followed my marks, and was able to unlock it and then found the power control widget. And bam! screen back to bright...
This might work for you!
Erm... In similar circumstances I found this worked...
I was trying out different Android builds and I found a screen brightness widget. It had various available levels of brightness, one being 0%. As soon as I selected it I felt pretty stupid as true to it's word it gave me 0% brightness placing me in a similar position to the OP.
My Solution. I used my (very bright) led torch to light the screen. By playing around with the angle and beam width I found I could just make out the on screen graphics enough to re-adjust the brightness level.
Simples!
Just as " Justblair " said .. you can place your device under a very bright light thus you'll be able to see the screen and what it's showing .. idk what build you guys are using but in cyanogen you can adjust the lowest dim level so that any app or widget tries to set the brightness to 0% it's automatically set to your preset, 15% for instance.
I've only faced this problem once
Is it absolutely necessary to flood the main thread with all these useless noob posts?
It really has nothing to do with Android development on HD2 and should be posted in the General section IMO.
kawazaki said:
Just as " Justblair " said .. you can place your device under a very bright light thus you'll be able to see the screen and what it's showing .. idk what build you guys are using but in cyanogen you can adjust the lowest dim level so that any app or widget tries to set the brightness to 0% it's automatically set to your preset, 15% for instance.
I've only faced this problem once
Click to expand...
Click to collapse
Cyanogen allows you a max dim level of 26 - which is too little on the HD2.
In Tasker, 30 is the lowest setting that still provides light. Maybe Cyanogen can be patched for the HD2 in coming builds?
Thanks for the tip on shining a bright light on the screen.
Another tip is to use Droid Explorer's "Screencast" feature, to view and control your Android's screen on your PC desktop. Of course, the brightness setting has no effect here.

[Q] Auto dimming my car mounted Nexus 7

So I've been doing some general googling, and I haven't come across a good solution for my issue, so I thought I would post it here. Nexus 7 is mounted on the dash of my car. Powers on and powers off (deep sleep), connects to hotspot fine, generally, is working great. HOWEVER, there is one feature that I would love to be able to replicate from OEM in dash systems that I've seen. I would like the screen to dim when the unit isn't actively being used. Not time out and go to sleep, just dim (or maybe even turn off the LED backlight). Then, when I tap the screen, I want the screen to come back to automatic brightness mode based on the ambient light sensor. I've found plenty of apps that will turn the screen on or off with various gestures and such, but they all seem to require disabling or otherwise changing the way the ambient light sensor works. From those of you that use these in your car, I'm hoping that you have some suggestions. Thanks in advance.
bigdogbts said:
So I've been doing some general googling, and I haven't come across a good solution for my issue, so I thought I would post it here. Nexus 7 is mounted on the dash of my car. Powers on and powers off (deep sleep), connects to hotspot fine, generally, is working great. HOWEVER, there is one feature that I would love to be able to replicate from OEM in dash systems that I've seen. I would like the screen to dim when the unit isn't actively being used. Not time out and go to sleep, just dim (or maybe even turn off the LED backlight). Then, when I tap the screen, I want the screen to come back to automatic brightness mode based on the ambient light sensor. I've found plenty of apps that will turn the screen on or off with various gestures and such, but they all seem to require disabling or otherwise changing the way the ambient light sensor works. From those of you that use these in your car, I'm hoping that you have some suggestions. Thanks in advance.
Click to expand...
Click to collapse
Hi, bigdogbts...
What you suggest certainly sounds feasible. I have no immediate solution, just some ideas/pointers.
Three pieces of software come to mind...
A Custom Launcher such as Apex or Nova. These give you a double tap gesture on the screen, which you can associate with some action to run... app, shortcut or 'activity'.
Lux Auto Brightness.
https://play.google.com/store/apps/details?id=com.vito.lux
This is capable of reducing the screen brightness right down to zero, such that the device looks likes it's turned off.
Tasker.
https://play.google.com/store/apps/details?id=net.dinglisch.android.taskerm
An app which is capable of automating all sorts of things on an Android device. You can associate an action instigated by the the user with a desired objective. Unfortunately, it has a bit of a steep learning curve... I bought it myself a few months ago, and I still haven't got around to really fully understanding it.
I suspect that if you can 'associate' Lux Auto Brightness (set with some pre-arranged brightness settings, ie., a completely dark screen) with a specified action (like double tapping the screen) with either Apex or Nova launchers (via gesture) or possibly with Tasker, maybe via a script...then you may be able to accomplish your goal.
As I've said, I think that what you're asking sounds possible... it's just a case of finding the right apps, and 'stitching' them all together. And maybe with a bit of tinkering with the apps I've mentioned, you can, hopefully, get something that works,
Good luck.
Rgrds,
Ged.
I think tasker can do something like that.

High pitch sound when display is turned on in joying head unit

Hi guys.
It seems that when the display of my 8" detachable screen joying unit is on, there is a very high pitch sound emmitted from the unit. If I manually turn the display off, it stops. Any ideas? Should I try grounding the display itself?
I figured out this had to do specifically with the brightness of the display. If it is ~70% on brightness, I get a high frequency whine.
alexx2208 said:
I figured out this had to do specifically with the brightness of the display. If it is ~70% on brightness, I get a high frequency whine.
Click to expand...
Click to collapse
Maybe - and this is just a guess, you could check the ribbon cable going from the head unit to the screen, and remove it to see if one of the contacts is dirty/corroded or just flaky. But as you mention if it's related to illumination it could be a ground issue.

Dasaita HU Brightness control stopped working

Hi,
The issue has appeared only in last few days.
- HU is running fine but always appears to be on the lowest brightness setting. It's usable by night but too dim for sunlight.
- If I try to adjust brightness, the UI shows the slider but it has no effect on the screen brightness.
- I've looked for and disabled any and all "auto brightness" settings which could be interfering.
- The unit can also auto-dim the screen when my headlights are on. I can tell it's getting this signal because the buttons on the unit light up when my headlights are on but it has no effect on screen brightness.
That's about all. Wondering if anyone has any ideas what could be going on? This is my 2nd Android Head Unit in as many years so I'm getting unbelievably frustrated.
Thanks.

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