Phone tracking app using SMS

[Ray Perkins]

As I don't have a data plan, I wrote an app to track a phone using SMS messages. It will send an email or text message with a Google Maps link whenever it detects motion greater than 200 meters, with a one minute update. Comments/criticism welcome. Maybe somebody will find it useful. Obviously, put in your own numbers.

// =======================================================

// =  Tracker - send SMS text whenever location changes  =

// =======================================================

// Apr 3, 2018

// app will work if minimized

// app will work if another app is in the foreground

// app will sort of work if phone is in sleep mode - wakes phone up, but possibly flakey!

// Droidscript keeps phone from going to sleep (inhibits screen timeout) no fix!

// will respond to a received text message - turn tracking on/off, send immediate location

var loc

var sms 

var ctr = 0

var oldLocLat = 45.433813  // just to initialize

var oldLocLon = -76.044660

var homeLocLat = 45.433813   

var homeLocLon = -76.044660

var SMSnum = ""

var SMSmsg = ""

var SendEvery

var oneMin = 1000 * 60     // check location every minute

var SendImmediate = 0      // flag to send location immediately

var SendToEmail = 1        // default

function OnStart()

{   

// Create vertical layout that fills the screen

var lay

app.SetOrientation( "Portrait" )

lay = app.CreateLayout( "Absolute", "Vertical,VCenter,FillXY" )

        lay.SetBackGradientRadial(.5,.7,.6, "#3300ffff", "#3300ff00" )  

app.AddLayout( lay )

    // Create location sensor

loc = app.CreateLocator( "GPS" )

loc.SetOnChange( loc_OnChange ) 

loc.SetRate( 4 )  

// Create SMS object

sms = app.CreateSMS()

sms.SetOnMessage( sms_OnMessage )

    

    // Set one minute interrupt 

    CheckGpsEveryMin = setInterval( CheckGpsEveryMin, oneMin )

    // Buttons: Send to email or phone

    btn1 = app.CreateButton( "Send to email" ) 

    btn1.SetPosition( 0.1, 0.1, 0.4, 0.1 ) // left

    btn1.SetOnTouch( btn_Email )

    lay.AddChild( btn1 )

    btn2 = app.CreateButton( "Send to phone" ) 

    btn2.SetPosition( 0.5, 0.1, 0.4, 0.1 ) // right

    btn2.SetOnTouch( btn_Phone )

    lay.AddChild( btn2 )

    }

function btn_Email()

{

    SendToEmail = 1

    app.SetScreenBrightness( 0 ) // dim screen to save battery

    // app.ToBack() // send app to back; screen will immediately return to bright, so not used

}

function btn_Phone()

{

    SendToEmail = 0

    app.SetScreenBrightness( 0 ) // dim screen to save battery

}

// Run gps to see if location has changed

function CheckGpsEveryMin()

{

    app.WakeUp()    // wake up app from sleep

    if( SendToEmail == 1 ) {

        SMSnum = "6245" // unique email number for Bell Canada

        SMSmsg = "mym...@gmail.com "

    }

    else {

        SMSnum = "5555555555" // phone number

        SMSmsg = "" 

    }

    loc.Start()     // start locator and send SMS to fixed email address

}

// Send SMS message once we get a location change

function loc_OnChange( data ) 

{ 

    if (SMSnum != "") {

        var dist = loc.GetDistanceTo( oldLocLat, oldLocLon )    // in km

        var home = loc.GetDistanceTo( homeLocLat, homeLocLon )  // distance to home

        if( dist > 200 | SendImmediate == 1 ) { // motion > 200 meters detected or send now

            ctr = ctr + 1  // speed not used as it is useless

        SMSmsg = SMSmsg + " #" + ctr + "  Bearing: " + data.bearing + " Home: " + (home/1000).toFixed(1) + " km away"

        SMSmsg = SMSmsg + " http://maps.google.com/?q=" + data.latitude + "+" + data.longitude

        sms.Send( SMSnum, SMSmsg )

        app.ShowPopup( SMSmsg + " > " + SMSnum)

        oldLocLat = data.latitude 

        oldLocLon = data.longitude

        }

    SMSnum = ""   // clear for next pass

    SMSmsg = ""

}

    loc.Stop()        // stop locator

    SendImmediate = 0

    //app.GoToSleep()   // put phone to sleep - does nothing without root access!

}

// Parse incoming SMS message for trigger words

function sms_OnMessage( number, msg )

{

    var UpperSMSmsg

    var w

    var t

    var x

UpperSMSmsg = msg.toUpperCase()

w = UpperSMSmsg.search("WALDO")     // send location data immediately

t = UpperSMSmsg.search("TRACKON")   // turn tracker on (default at power up)

x = UpperSMSmsg.search("TRACKOFF")  // turn tracker off

if( w >= 0) {         // reply to "Waldo" trigger word...

        app.WakeUp() 

    SendImmediate = 1

        loc.Start()       // start locator     

}

else if( t >= 0) {    // remotely turn on tracking...

        CheckGpsEveryMin = setInterval( CheckGpsEveryMin, oneMin ) 

        SendImmediate = 1 // send immediate response

        loc.Start()       // start locator     

}

else if( x >= 0) {    // remotely turn off tracking...

        clearInterval( CheckGpsEveryMin )

}

    if( SendToEmail == 1 ) {

        SMSnum = "6245" // unique email number for Bell Canada

        SMSmsg = "mym...@gmail.com "

    }

    else {

        SMSnum = "5555555555" // phone number

        SMSmsg = "" 

    }

}

[John Constatine]

it would be interesting, to leave the service in the background only to be activated when it received an SMS and that the sms was not shown operate me in the background too

so that it does not waste battery, it is activated only when it receives the command via email or sms, it activates and returns the location

[Ray Perkins]

My new version does just that, I use a service to run the gps and sms functions. The target email address and phone number is read in from a text file, so I don't have to recompile if I change it. I'll attach as text files...

There is an issue with this, as my one minute interrupt often interrupts only every few minutes. I have tried everything to get around it, to no avail. I think it's just how the OS works in sleep mode.

I would also like to suppress the phone's notification when I send a command SMS so the recipient isn't alerted, but I doubt that is possible.

[John Constatine]

you have the solution for notification of sms in the bar to study how to make a message or status change in firebase, in real time there could have an application to activate in the other cell recovering what needs without needing a web server, but there needs internet, but your project is very interesting I'll study it

[Steve Garman]

You're not giving your setInterval a chance.

You are using a global function CheckClock and a global variable CheckClock

I am amazed your service runs at all.

Try renaming one of them.

[Ray Perkins]

Thanks! I'll look into it. It isn't the first time I've done some thing similar. (Aren't you in England? It's early morning over there!)

[Steve Garman]

Yeah,it's just coming up to 2 a.m.

It's no wonder I'm such a grumpy old man.

[Ray Perkins]

I tried the fix in a test file. It seems better, but it's still not all that consistent. I'm using a 5 second interrupt to look at the clock...

• App.WriteFile( ./Test.txt, 21:09:48 , Append, )
• App.WriteFile( ./Test.txt, 21:10:03 , Append, )
• App.WriteFile( ./Test.txt, 21:11:24 , Append, )
• App.WriteFile( ./Test.txt, 21:12:28 , Append, )
• App.WriteFile( ./Test.txt, 21:13:00 , Append, )
• App.WriteFile( ./Test.txt, 21:14:29 , Append, )
• App.WriteFile( ./Test.txt, 21:15:04 , Append, )
• App.WriteFile( ./Test.txt, 21:16:00 , Append, )
• App.WriteFile( ./Test.txt, 21:17:23 , Append, )
• App.WriteFile( ./Test.txt, 21:18:23 , Append, )

function OnStart()

{   

    // Set fast interrupt to check clock

    CheckxxxClock = setInterval( CheckClock, 5000 ) // 5 second interrupt

}  

// Run gps once a minute to see if location has changed (5 sec. interrupt)

function CheckClock()

{

    var d = new Date()

    var NewMin = d.getMinutes()

    if( NewMin != OldMin ) {

        GPSrunning = 0

        app.WriteFile( "./Test.txt", GetTimeStamp() + " \n",  "Append" )

        OldMin = NewMin

    }

}

// Get current time

function GetTimeStamp ()

{

    var timestr

    var d = new Date()

    var hr = (("0" + d.getHours()).slice(-2))

    var min = (("0" + d.getMinutes()).slice(-2))

    var sec =  (("0" + d.getSeconds()).slice(-2))

    timestr = hr + ":" + min + ":" + sec

    return timestr

}

[Ray Perkins]

Found it! Android has a "Doze mode"; the system gradually reduces it's response time when asleep. https://lifehacker.com/how-android-doze-works-and-how-to-tweak-it-to-save-you-1785921957

This is exactly what I am seeing when I ran a test program overnight in sleep mode. Following plot file shows the number of seconds between responses (60 seconds is the expected response time, I got anything up to 1800 over an 8-hour period).

I turned off battery optimization for Droidscript and am running another test to see if this fixes the issue of slow responses in sleep mode.

[Ray Perkins]

Well, the fix didn't work. Back to the drawing board!

[Jared]

I didn't look too closely at the code so sorry if this ends up irrelevant, but did you consider try using the accelerometer to detect movement as a way to send the loc update? you could use magnetometer / accelerometer combo or something like that...

[Ray Perkins]

Issue isn't detecting a location change. Issue is the processor shuts down for too long in sleep mode. I'm running a test to see if I can stop it from doing that by forcing a wakeup if I detect a slow response from the OS.