Database Users

Distance between two devices (with a high accuracy)

Hi,
i need a Tool to calculate the distance of two devices with an accuracy of about 1 meter by a distance of 0-3 meter.
GPS doesn't suite this needs, but i guess bluetooth signal-strength does.
I was looking up the android bluetooth api but can't find anything to read signal strength. Anyone any tips how to get on the strength of the bluetooth signal?
thanks, exec

Cool idea
That is a pretty cool idea. I'm not a developer but I like it.

Another way is to use sound along with a tcp/ip or bluetooth connection
1) keep track of each phone's clock (or difference between)
2) make the second phone chirp/beep and record
a)the time the second phone started the beep
b)the time the first phone heard the beep.
3) calculate the distance using the amount of time it took to hear the beep.
note: the speed of sound may differ slightly but should be within your accuracy range
see http://www.sengpielaudio.com/calculator-soundpath.htm for an example.

nice idea, i'll keep this in mind. But for the moment it doens't fit my needs, cause it can be a loud enviorment with a lot of phones where i have to find the nearest one

exec87 said:
nice idea, i'll keep this in mind. But for the moment it doens't fit my needs, cause it can be a loud enviorment with a lot of phones where i have to find the nearest one
Click to expand...
Click to collapse
A pure tone at an agreed upon frequency will be hard to miss. If you have the service installed on all the phones you can query each one in turn and then figure out which one is nearest.

do you know any example how to analyse the frequenze of the current recorded tone?

exec87 said:
do you know any example how to analyse the frequenze of the current recorded tone?
Click to expand...
Click to collapse
This looks promising
http://code.google.com/p/moonblink/wiki/Audalyzer

sry but if you want to measure distances of up to 3 metres with the help of sound speed, that wont work
sonic speed is 343m/s, that means it takes 0,002.9sec for one meter to pass.
or otherwise, it would pass the 3 meters in 0,008.7 sec for 3m
to compare it, a nexus one would do a clock cycle every 0,000.000.01 seconds, and in that time, the sound weave moves 0,000.000.343 metres.
So if you're optimistic and it takes "only" 100.000 to 500.000 cycles to sample the sound AND compare it to the clock, your diffrence of that two cases would be 3cm to 15cm, so you got a standard "uncorrectness" of about 12cm.
but thats if it takes 100.000 to 500.000 cyles, and it would be worse if it takes more time or if the clock is not 100% correct (this example is with a 100% exact clock)
if the clock is only correct for 1ms, you must add another 30cm of "uncorrectness"

arthofer said:
So if you're optimistic and it takes "only" 100.000 to 500.000 cycles to sample the sound AND compare it to the clock, your diffrence of that two cases would be 3cm to 15cm, so you got a standard "uncorrectness" of about 12cm.
but thats if it takes 100.000 to 500.000 cyles, and it would be worse if it takes more time or if the clock is not 100% correct (this example is with a 100% exact clock)
if the clock is only correct for 1ms, you must add another 30cm of "uncorrectness"
Click to expand...
Click to collapse
Dont think sampling and processing cpu-time matters so much as to make this method unusable.
a)The sample time does not matter. It will be:
system time when the recording started + time within the sample where the frequency is found (comparison is part of post-processing). The sample window can be fixed at 0.5 seconds (or less) as 343/2= 171.5m is huge.
The phone emitting the frequency can be triggered over wifi/radio and that will be very very quick (speed of light+message processing time)
b)the time taken for the comparison will not matter as its done after the event has occurred. (post-processing)
The 1ms clock problem can possibly be overcome by using System.nanoTime()

exec87 said:
Hi,
i need a Tool to calculate the distance of two devices with an accuracy of about 1 meter by a distance of 0-3 meter.
GPS doesn't suite this needs, but i guess bluetooth signal-strength does.
I was looking up the android bluetooth api but can't find anything to read signal strength. Anyone any tips how to get on the strength of the bluetooth signal?
thanks, exec
Click to expand...
Click to collapse
Maybe use a ruler?
Sorry that I can't stop myself doing this after reading your question
ok, to a more serious side, if bluetooth don't work, then maybe use wi-fi. don't know if they have the api for wi-fi to measure signal strength neither.

What if you had one phone act as a Wi-fi hot spot, then the other connect to it. Then someone write an app that will use GPS to determine the distance between the two. IDK, just a shot in the dark. I really dont have a lot of knowledge about that stuff.

You could use a PRF (pulse repitition frequency) but I have no idea what these would be for bluetooth or even the radios. Honestly I think using the GPS coordinates and distance equation would be the easiest.

Unfortunately our consumer gps's rarely go down to 1m, and that the max... And it will likely not work indoors

britoso is right... i'll keep the hint with wlan strength in mind, but atm i'm working at the audio idea... it's a little bit hard, and first tests show that an accuracy of 1-2 meters is possible... i'll reply if i'm done.
however i'm thankful for EVERY input
edit: i think i will give up... the delay of analyzing the sound is between 150ms and 250ms... and i can't see in code where this 100ms difference come from... i think i need a kind of realtime system to build this...

exec87 said:
britoso is right... i'll keep the hint with wlan strength in mind, but atm i'm working at the audio idea... it's a little bit hard, and first tests show that an accuracy of 1-2 meters is possible... i'll reply if i'm done.
Click to expand...
Click to collapse
however i'm thankful for EVERY input

exec87 said:
edit: i think i will give up... the delay of analyzing the sound is between 150ms and 250ms... and i can't see in code where this 100ms difference come from... i think i need a kind of realtime system to build this...
Click to expand...
Click to collapse
If you can PM me the code I can take a look.
I didn't want to start coding this because
a) I only have one phone
b) havent used the bluetooth API.
I'm comfortable using tcp/ip though

i don't know if this is impossible.. but i think its worth the try.. i'm horrible at development nor i have taken any advanced math courses... so heres the concept:
how about getting two people hold a phone facing each other.... they both have to hold the phone upright and straight...(using Spirit Leveler)
with one of the phones... the app takes a picture of the other phone... and asks you to point out the phone's height in the picture...
and given the real height of the phone (this should be a dropdown box for known phone types.. and custom if you want to use a credit card... or anything else u find) it should tell you the height..
possible?

oh and one more thing.. u can have the phone's screen facing the camera with white background and black DOT... if that helps to do live tracking of the phone's size...??

britoso said:
If you can PM me the code I can take a look.
I didn't want to start coding this because
a) I only have one phone
b) havent used the bluetooth API.
I'm comfortable using tcp/ip though
Click to expand...
Click to collapse
This is what i first thought of when i saw this thread. Why not establish an ad-hoc network and send over a series of pings, each one send over one packet of info from phone A to phone B. have phone B process the information and show its good then send it back to A and have it verify it also. Then based of this data(and experiments to see hwo long it takes to process the information. you the time from a-b-a to calculate the distance.
This is all hoping that the speed of travel of the packet is not to fast to calculate the distance lol.

Any results?
This is the exact answer I'm looking for, which method produce better accuracy, is it the sound (measuring time difference) or the signal strength test (measuring the RSSI)

[Q] Cell signal graphic on "CM9 by elginsk8r"

Just wondering if the appearance of the cell network signal is normal (shows its like half full)
I've flashed a few different radios and none seem to get the signal higher than what looks likes about 50% (as measured by the graphic)
Is this just how the graphic appears?
i can't link because i'm new but the picture is at
dl.dropbox.com/u/9195034/signal.png

Are you losing signal or having reception problems?
Be careful flashing radios too often. A bad flash equals a bricked phone.

willshep said:
Just wondering if the appearance of the cell network signal is normal (shows its like half full)
I've flashed a few different radios and none seem to get the signal higher than what looks likes about 50% (as measured by the graphic)
Is this just how the graphic appears?
i can't link because i'm new but the picture is at
dl.dropbox.com/u/9195034/signal.png
Click to expand...
Click to collapse
Same issue. I use WiFi so much I hadn't noticed it. I am able to get full WiFi bars though. Maybe the software isn't coding to report a high signal even when it's available? I'll have to test this again while standing/driving next to a cell tower.

If the signal is reporting the same at all times no matter what, it's probably b/c he forgot to add a line to the build.prop
I spotted this in zips' older builds and he fixed it when I told him what it was and what he needed to do

I2IEAILiiTY said:
If the signal is reporting the same at all times no matter what, it's probably b/c he forgot to add a line to the build.prop
I spotted this in zips' older builds and he fixed it when I told him what it was and what he needed to do
Click to expand...
Click to collapse
Care to share with the rest of the class what this line is?
Sent from my HTC Glacier using XDA

I have the same issue. Im guessing its because the build isnt finished yet. Also, do any of you have the wifi calling feature on this rom? When i first got the phone, i can use the wifi calling whenever I am not in range of a signal or something, like in my basement, but now that i flashed my phone I dont have it, and i dont know where to get it from.
Any help would be appreciated

edit system/build.prop and add
ro.telephony.ril.v3=signalstrength
reboot and done
hxxp://dl.dropbox.com/u/9195034/Screenshot_2012-04-18-13-56-58.png

How to increase wifi signal on any TW Rom

Just thought I'd share. It's a trick I learned on the Samsung epic OG
No root needed very simple
Go to dialer pad
Enter *#0011#
When the info screen appears hit the menu hard key
You'll see wifi.... Click it
Next you'll see by default powersave mode is enabled. (it sets signal power to 6 out of 10)
Uncheck powersave mode
And that's it. Watch the signal on your wifi in areas where you had maybe 1 bar you'll have 3 now etc.
Enjoy
Sprint GS5 Moars 6.2

This screwed up my battery

OP, Can you undo this if it gives any issues (like the battery one above)?

arozer said:
OP, Can you undo this if it gives any issues (like the battery one above)?
Click to expand...
Click to collapse
yes do the exact same thing but check the power save box.
i see no battery difference at all ive been doing it since the samsung epic. in fact theres a way to allow LTE to connect at a higher decibel than normal (then you'll have LTE at farther distances) but i cant find the proper code yet. its under Entry RX
in the dialer codes

RollingThunder94 said:
This screwed up my battery
Click to expand...
Click to collapse
This is expected IMO. I mean you are physically unchecking "power save" which I believe increases the gain on the amplifier. Unless you are actually suffering from poor wifi signal in an area where there's nothing you can do about it, I would leave it as is. If you're having wifi issues in your home, I would upgrade hardware or add a wifi repeater before messing with the phone.

[MOD]Brighter Torch for Z5C

This is a very powerful mod that changes the brightness of the Xperia flashlight / torch.
This can cause damage if left on for extended periods of time. It is advised you install the medium version.
Source
Pre-Caution:
I take no responsibility to any burnt hands, burnt phones, or bricked phones. The chances of getting into a brick or bootloop is very low and I will aid you as much as possible, but will take no responsibility for this happening.
CAUTION:
The extreme version sets the torch to 1,000,000 Ua - in other words, its basically an industrial flashlight now, meaning it will get very hot, very quickly. Please take caution with using the extreme version.
DOWNLOAD:
Medium
Extreme
Uninstaller
SmarTemperature (To increase the temperature limit)
Installation:
1. Have a rooted device with /system access (So not the temp root method)
2. Download and move one of the zips to your SD Card
3. Enter recovery and backup your phone (Incase you want to revert back to default values)
4. Flash the Torch ZIP, and then flash the SmarTemperature ZIP
5. Enjoy!
Code:
# LED If setting for Indicator(uA)
if_indicator_level = 4125
# LED If setting for Torch or video recording (uA).
if_torch_vr = 500000
# Vf measured at factory (mV).
vf_factory = 2869
# Min voltage for VBat (mV)
v_batt_min = 3500
This mod works by modifying /etc/flashled_calc_parameters.cfg with custom values
NOTE:Take caution if you plan to modify this config file yourself.​
XDA:DevDB Information
Xperia Brighter Torch Mod, Tool/Utility for the Sony Xperia Z5 Compact
Contributors
nzzane
Version Information
Status: Stable
Current Stable Version: V2
Stable Release Date: 2016-10-04
Created 2016-10-03
Last Updated 2016-11-22

Reserved:

My device shutdown when turning on the LED on medium, could you provide the initial value please?

raphoun said:
My device shutdown when turning on the LED on medium, could you provide the initial value please?
Click to expand...
Click to collapse
What firmware are you on & what Kernel are you using?
I have updated the OP with the first few lines of code for the medium version - as well as adding an uninstaller zip

nzzane said:
What firmware are you on & what Kernel are you using?
I have updated the OP with the first few lines of code for the medium version - as well as adding an uninstaller zip
Click to expand...
Click to collapse
The last firmware with OM5Z kernel. Thanks for the uninstaller

raphoun said:
The last firmware with OM5Z kernel. Thanks for the uninstaller
Click to expand...
Click to collapse
Very weird, do you still have "Allow OEM Unlock" enabled?

I am having the same issue here...
I am on Xpower 5.0 androplus kernel and it also happened on previous kernel... what could be the problem?

mine shutting down to , last stock rooted rom

If someone can find where the temp warning config file is, I will update this mod with that in.
i have tried to increase the temp warning temp but it has failed..

nzzane said:
If someone can find where the temp warning config file is, I will update this mod with that in.
i have tried to increase the temp warning temp but it has failed..
Click to expand...
Click to collapse
i dont think its the temp warning because my device doesnt over heat at all it just turns off...
if it was temp warning then it should get hot first then shut down am I right or ?

hey every one I just found this :
http://forum.xda-developers.com/xpe...-smartemperaturex-best-balanced-s810-t3438890
smartemp mod fixed my issue! had the extreme mod installed and turned on for couple of minutes , no shut down no warnings and also device doesnt even heat after the first couple of minutes on EXTREME TORCH
hope it works for you guys 
 @Gewiz told me about this so credit for him

madshark2009 said:
i dont think its the temp warning because my device doesnt over heat at all it just turns off...
if it was temp warning then it should get hot first then shut down am I right or ?
Click to expand...
Click to collapse
From what I have seen. The device, for Some reason, detects that it is heating quickly even thought it's not. This prompts the over heating warning.
It could be that the phone has a procedure in place to stop modification of the flashlight, but I have not seen this yet

madshark2009 said:
hey every one I just found this :
http://forum.xda-developers.com/xpe...-smartemperaturex-best-balanced-s810-t3438890
smartemp mod fixed my issue! had the extreme mod installed and turned on for couple of minutes , no shut down no warnings and also device doesnt even heat after the first couple of minutes on EXTREME TORCH
hope it works for you guys
@Gewiz told me about this so credit for him
Click to expand...
Click to collapse
Thanks, will add this to the OP

Hi, first of all, sorry in advance if it is a stupid post, I am no developer. Is it possible that everybody is running an extreme version and getting thermal problems because of a typo? I ve tried this mod (the medium version), and read the thread.
I opened the default configuration file, and compared it to the same file in the zip.
Two values change:
___________________default_____Medium________Extreme
if_indicator_level = _____3125_______4125___________5125
if_torch_vr = _________25000_____500000_________1000000
Isn't that strange? In the medium and the extreme versions, the indicator current is increased by 30% and 60% respectively, but the flash led's current goes from 25k to 500k and 1 million
The values seem to be in μA, that makes the default value of 25.000μA equal to 25mA, which seems about right for a led.
I ve modified the medium vetsion to the value "if_torch_vr =50.000 instead of 500.000. No shutdown, but I cannot judge how bright it is right now.

argotera said:
Hi, first of all, sorry in advance if it is a stupid post, I am no developer. Is it possible that everybody is running an extreme version and getting thermal problems because of a typo? I ve tried this mod (the medium version), and read the thread.
I opened the default configuration file, and compared it to the same file in the zip.
Two values change:
___________________default_____Medium________Extreme
if_indicator_level = _____3125_______4125___________5125
if_torch_vr = _________25000_____500000_________1000000
Isn't that strange? In the medium and the extreme versions, the indicator current is increased by 30% and 60% respectively, but the flash led's current goes from 25k to 500k and 1 million
The values seem to be in μA, that makes the default value of 25.000μA equal to 25mA, which seems about right for a led.
I ve modified the medium vetsion to the value "if_torch_vr =50.000 instead of 500.000. No shutdown, but I cannot judge how bright it is right now.
Click to expand...
Click to collapse
Hey, not a stupid post - So with the Z5 series they have a pretty low thermal limit, so thats why it is so retarded and shuts down, unless you have flashed the thermal limit raiser. (created for the purpose of the z5 thermal limit being so low)
Let me know if you notice a change in brightness, as the I may have miss-typed some of the code

Hi, I haven't looked it since.
I did not want to try that thermal mod. The posts on its thread weren't very encouraging. Decided to leave it set at if_torch_vr =50000
I can test again with other values but it won't be in the next days. Probably when I decide to jump to nougat

The Medium mod send my phone in temperature protection, if someone have Xposed try this module to increase the temperature limit
http://repo.xposed.info/module/michele2.thermal.disabler
Edit:
The module does not solve the problem, after a minute with the LED on the Z5c turns off after a temperature warning message.

cioce said:
The Medium mod send my phone in temperature protection, if someone have Xposed try this module to increase the temperature limit
http://repo.xposed.info/module/michele2.thermal.disabler
Edit:
The module does not solve the problem, after a minute with the LED on the Z5c turns off after a temperature warning message.
Click to expand...
Click to collapse
https://forum.xda-developers.com/showpost.php?p=69743947&postcount=11
Did you tried that? I recommend v1.6.1

EDIT
WORKING FOR FEW SEC AND SHUTTING DOWN!
on my 1.54
im using green kernel for stock rom

Links dead, reupload? Thanks

Lg v20 US996 device keep changing the Min and max cpu frequency by itself

(FIXED)
Assalam o alaikum
Hi
I've an lg v20 Us996
Unlocked bootloader amd rooted
When i first bought this phone it was liquid and buttery but after few days device starts lagging and stucking,i farctory restored it but no fruit then plan to root it and j rooted it but still the device keep lagging.
I've strictly monitored the activities of my cpu and the thing which i captured is that My cpu min and max frequencies keep changjng by it self which makes it laggy.
Like the max frequency is 2.15, but i automatically scales down to 400mhz,900mhz,1036 and some others frequencies which slow down the device.
Even if i use kernal auditor and set the max frequency to sclae up still it automatically changes.
I've used 3different kernals and on stock based rom(weta rom)
Still the same issue.
Is it a hardware issue or software issue?
Thanks in advance

First off, this shouldn't be posted in the development section as it's unrelated to development.
Second, the CPU is supposed to scale, change frequencies depending what the phones doing, 307 MHz-2.15 GHz. If the CPU stayed at 2.15GHz, you would face dramatically shortened battery life and eventual overheating. Thermal throttling is a necessity. LG is a bit more conservative compared with some other vendors I have noticed but if the issue has just started I would look more towards a particular app running afoul.

+1 for app craziness... If you utilize any 3rd party stores, ie Aptoide,Blackmart,ect... Then I HIGHLY suggest getting some sort of active antivirus on your device at this point. Malware is getting good enough to bypass Google Play filters, what do you think is going on on the less-than-monitored stores? Mayhem... Silent, costly mayhem. Chances are, if your CPU is doing all of that randomly, and especially if it is getting warm for no reason/battery drain from sitting and doing nothing, chances are your device is part of an Ethereum/Bitcoin MineNet, making someone money... I suggest getting a Norton AntiMalware scanner.. I KNOW.. Norton blows on windows.. But it cleared my device of the exact same plagues... Just watch out for that FinSpy... That bites.... I just had a bit of that as part of an entire multi-zero-day attack on my networks I am in the process of writing up reports for CVE's.... It made a mesh network between anything with Wifi, Bluetooth, or IR... Kernel level on windows 10... and with the climate of today, and how you started the thread, if I were you, and if you connect your phone to your computer, and if you run Windows 10, then I would check your MBR, and your bootsec as well for possible buffer overflows that lead to code injection that might send your device booting elsewhere while images are being made of your system... This is a long shot... But these are the symptoms I experienced, which led me to literally watch my logcat with aLogCatView live for about 2 hours, watching my mic go on and off, and then once, in light blue letters, I caught FinSpy, with nothing after those letters... just a notation that scrolled on...
Now more than ever, exercize proper security. Especially on a device who's sec has been bypassed by the same exploits that the malware will use to gain access to do damage. We praise DirtyCow for giving us our phones, truly. But the nefarious praise it for giving THEM OUR devices... Just my .2

Ducter said:
First off, this shouldn't be posted in the development section as it's unrelated to development.
Second, the CPU is supposed to scale, change frequencies depending what the phones doing, 307 MHz-2.15 GHz. If the CPU stayed at 2.15GHz, you would face dramatically shortened battery life and eventual overheating. Thermal throttling is a necessity. LG is a bit more conservative compared with some other vendors I have noticed but if the issue has just started I would look more towards a particular app running afoul.
Click to expand...
Click to collapse
The problem was with thermal engine which I've fixed

maxi65 said:
The problem was with thermal engine which I've fixed
Click to expand...
Click to collapse
How did you fix it?
Sent from my LG-H918 using XDA-Developers Legacy app

Assalam o alaikum
You just simply have to replace thermal engine configuration file form your system/etc folder using root explorer and everything will be fine and smooth (in sha Allah)

Use root explorer
Go to system and find for 'etc' Folder
Then in etc folder find ' thermal engine 8996' and create a backup of that file by simply copy that file to your internal storage or wherever you want
Then replace this file with that file which I've provided you in attachment
Note: the attached file is in 'txt' format
Change the extension from 'txt' to 'conf' by simply renaming the file then replace it.

Thanks man You saved