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[Q] Can my N7 completely turn off when power is disconnected?

hi all
like many others iv put my nexus 7 into the dash of my car. i was wondering if there is an app or way for my nexus to turn itself off when i turn the car off. iv figured out how to make the device turn on when power is restored to the device but still not sure how to turn the device off.
also would anyone know why when the nexus turns on, it immediately mutes itself? it is connected via 3.5mm jack 100% of the time and tasker opens up power amp but other then that i don't know what might be causing it. any help is appreciated on both issues
cheers
tittysprinklez

Tittysprinklez said:
hi all
like many others iv put my nexus 7 into the dash of my car. i was wondering if there is an app or way for my nexus to turn itself off when i turn the car off. iv figured out how to make the device turn on when power is restored to the device but still not sure how to turn the device off.
also would anyone know why when the nexus turns on, it immediately mutes itself? it is connected via 3.5mm jack 100% of the time and tasker opens up power amp but other then that i don't know what might be causing it. any help is appreciated on both issues
cheers
tittysprinklez
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If you have tasker installed, create a state which is dependant on battery power - as an exit task tell the tablet to wait for 10 seconds, then call the misc->reboot action with type shutdown to turn the tablet off. The wait 10 seconds it to prevent it powering off when you are cranking the car...
If you just want to turn the screen off, not power the whole tablet down, there's a tasker action Display->System Lock which will turn the screen off..
You could also use tasker to change the system volume for you if you needed as a workaround...
*edit* - BTW - the tasker reboot options don't gracefully reboot / shutdown, so if you have apps running, there's a chance that you may lose data. To do a 'graceful' reboot / shutdown, you are better off using the secure setting plugin...

shutdown process with eunavi

Hello everyone,
I just installed a eunavi head unit.
First of all it doesn't have acc delay off function. There are no options in the menu and the seller told me that it's not possible. I tried to connect the acc line with an external battery but the unit still turns off while cranking the engine. (I have verified that all the connections are correct). I suspect that it has to do with the voltage drop of the car battery while cranking the engine. My next project will be to install an auxilary battery (a small one, 12V 2Ah). While the engine is running, the unit will be using the main battery. The small one will be there to supply current while the engine is cranking and it will be charged from the car while the alternator is working. It will also power the acc line using a delay off circuit.
My question has to do with the shutdown process. When I put the key on the off position, the unit turns off almost immediately. There is no any message on the screen telling me that it's turning of. I put an ammeter on the power line to see what's happening while it's turning off. After cutting the acc line, in less than 1", the current dropped from ~900mA to 50mA, after 1" to 33mA and then to 16mA. After 3-4" it dropped to 3mA and it stays there. Is this normal? Could this behaviour harm the unit? Should I be concerned? How could I check it's shutting down correctly?
The power button doesnt turn off completely the unit. It turns off the lcd but the unit still gets 700mA. There is a secret menu that could change the button function from "false shutdown" to "true shutdown". If I select the "true shutdown" and press the button the unit turns off like when I cut the acc line. Is this a good sign?
Thank you

anyone?
I've noticed that if I shutdown the unit (by turning off ACC power) while some apps are open (like the music is playing), the next time I turn it on, the apps are opening automatically. It this a good sign that the unit is shutting down properly or the same thing would happen if it shuts down violently (by cutting the power line).
Could anyone explain us how the MCU shuts down the unit properly? Does is trigger a pin on android to perform shutdown or it sends a command using a communication protocol (like UART).
I don't know what happens on mine but I suspect that the MCU cuts the power on the Android if it doesn't get power on the ACC line. I was thinking if that would be possible to send a shutdown signal on Android (using hardware or software mod) when the ACC power is off.

[Question] Head Unit that doesn't shut down / go to sleep

Hi,
I've bought a new Head Unit, and I wired everything on the car.
It's working like a charm, but, there a big but.
The Head Unit which should go to sleep / deep sleep or whatever when I remove my car key after 30 seconds, stays on.
For the time being I've unpluger the ACC cable (the red wire) so that the Head Unit only receives power when the car key is plugged in.
Do you know why am I facing this Issue and how to resolve it ? I had hope to enjoy a fast boot and not a full boot everytime I use my car.. it would be nice
I have another question also, if you know about it, I'm trying to get the light buttons always on, because they're not very visible to me. Si I went to the special menu (with the 126 code) and tried changing the parameter "Power LED control" to "By Power" instead of "By head light" but they still won't turn on unless head light is on. Am I missing something ?

I'm not sure what head unit you have but a) what is your amp wire from the head unit connected to? B) there's is usually an illumination wire, what is that connected to?
Sent from my SM-G950U using Tapatalk

Also do not know what head unit you have but it sounds like it is not wired up correctly.
If you dont get much help on these forums maybe go visit an auto electrician as they should be able to advise further.

Incrase time "power off delay when acc off"

Hi, I bought a Chinese navigation for a Peugeot 307, the problem is that the maximum time I can set to stay on after cutting the ignition is a maximum of 5 minutes, I need more time because I often listen music at a nature outing. Do you want a solution? Navigation has android 10. I will attach some pictures with the navigation.

Please post a picture of the setting for this.
The ignition has 3 positions...OFF, Accessory, On. On is a temporary position used to start the engine.
If I'm not mistaken, the setting is for how long it will take the head unit to completely turn off after the ACC has no power and the ignition is OFF. So, if you leave the ignition in accessory mode, then the radio will continue to be powered during the entire time. My Sorento has a 15 minute timer where if it is left in accessory mode, it will power down that mode...to save battery. When this happens, I open and close the door.
When you turn the ignition completely off, the head unit stays powered for a brief period of time. I believe the setting you are referring to is the length of this period of time. Maybe it was designed this way so that it can shut down properly. I believe this is a new feature. I have a TEyes SPro where this setting does not exist. The setting is only available on newer models and newer firmware, I believe.

Hi, my ignition has only two positions, off and on, I miss the accessories position. I understand that this is the case for all 307 models. In the first image you have the starting position, when I put it in this position, the navigation starts, but for a maximum of 5 minutes I can set it in image 2. I checked with a meter and the pulse which gives it is to the bus, from 3 to 4.5v when the ignition is on. Is it possible to modify a file in the android system to increase that shutdown time by a maximum of 5 minutes as much as possible?

Are you sure there is no accessory position? I believe most, if not all, cars have this position. I don't think I've seen a car without an accessory position.
I have a push button start and if I push the button without pressing the brake pedal, it goes into accessory mode. I need to press the brake pedal at the same time that I press the ignition button to start the car.
I found two different owner's manual for a Peugeot 307 that shows there should be an accessory position. So, I think this should do what you're looking for. As for the "file" to increase the shutdown time, I'm not aware of any way to do this:
I found the manuals here:
PEUGEOT 307 AUTOMOBILE MANUAL
View and Download PEUGEOT 307 manual online. 307 automobile pdf manual download.
www.manualslib.com
PEUGEOT 307 OWNER'S MANUAL Pdf Download
View and Download PEUGEOT 307 owner's manual online. 307 automobile pdf manual download.
www.manualslib.com
If yours is like the image with 3 positions, then it doesn't really seem like an accessory position, but it looks like that may be your only option.

Another option occurred to me. ACC provides power when in the Accessory or ON position. One option is to provide power to ACC even when the car is off. For example, you can add a switch that normally connects the car ACC wire to the head unit ACC wire. When you want to turn the head unit on where no power is available on the ACC car wire, you flip the switch to an alternate power source for the head unit ACC wire. This could be something like an external power supply or have the ACC connect to the car 12V wire. When I was testing my head unit on the kitchen table, before installing it into my car, I connected both 12V and ACC on the head unit to a jump starter.
You should note that there could be other issues with the car battery DISCHARGING TOO MUCH if you forget to switch back and you'll be stuck and need a boost or worse....damage your car battery. Also, you should make sure that the voltage added to the car ACC wiring does not feed back to the car...I'm not sure what would happen in that case....maybe other bad things.
If your not sure about this hardware modification, you could always have someone at a stereo shop or someone with similar skills have a look and/or do this for you.
NOTE: This should go without saying for any information you are provided, but, these are suggestions and ideas and you should verify them for yourself. Any issues that arise are solely your responsibility.

I'm sorry mate, but P307 have battery power saving feature. there is no ACC ON position, but if you leave key in second position, after few minutes battery icon will show or start blinking and car will go to 'sleep" - turning off all accessories.

Android Head Unit keeping BMW from entering sleep mode.

I recently installed an Android Head unit in my 2012 BMW 128. I have the HiFi non HK stereo.
Sound works fine. Steering wheel controls also work (set for an E90 to match the canbus decoder that was included. There is no option for E82)
GPS/WiFi, etc all work as expected.
The issue I'm having is that when I shut the car off and lock it, it never goes to sleep. Normally it takes 15-20 minutes for it to finish all the checks and enter sleep mode but with the power connected to the Android unit, that process never stops. I've waited hours and came back to it still making noises, the start button periodically lighting up, etc.
If I disconnect the power cable to the head unit/canbus controller, the car goes to sleep as expected. I have gone into the factory settings and disabled sleep mode which causes the stereo to have to boot when you start the car but that also didn't resolve the issue.
I have not connected the extra yellow cable to the fuse panel - I understand that's for clock/radio presets but those are not of concern at the moment.
I can't find any settings on the head unit that would be causing this. The yellow power appears to flow through the canbus controller to the head unit because if you disconnect the canbus controller the head unit will not power on so I tend to think it's likely the canbus controller that's the culprit.
Just wondering if anyone else has had a similar issue and how they resolved it?

Connected the yellow cable to the power for the 12v outlet and the car goes to sleep as expected.

Bumping my own old thread.
Connected to fuse #2 in the panel and the car would sleep and the stereo retains clock, etc but I get a battery drain warning.
Went back to 12v outlet and no more battery drain but it cold boots every time I start the car.
If anyone stumbles across this and has a solution please let me know!