GPS speed is extremely unnacurate

[Kkraft]

(English from translator probably some word is wrong lol)
hey guys, I’m doing a school work using corona, i use gps speed to fire a simple image and song, but this extremely inaccurate, 90% times it returns 0 speed, even if i run with my cellphone, heres the code:

-----------------------------------------------------------------------------------------
--
-- main.lua
--
-----------------------------------------------------------------------------------------
--SCRIPT POR KKRAFT PARA TRABALHO DE CIENCIAS!

local fundo = display.newImage("fundo.png")
local img = display.newImage("rosto.png")
local imghappy = display.newImage("rostohappy.png")

--Inicio
fundo.width = 10000
fundo.height = 10000
img.width = 350
img.height = 300
imghappy.width = 350
imghappy.height = 300
imghappy.isVisible = false
img.x = display.contentCenterX - 5
img.y = display.contentCenterY
imghappy.x = display.contentCenterX - 5
imghappy.y = display.contentCenterY

--Vibração

local function acelerometro(event)
    if event.zGravity >= 0.1 or event.xGravity >= 0.1 then
    system.vibrate( )
end
end
local function speedfunc(event)
    print( event.speed )
    if event.speed >= 0.0001 then
    local enginefx = audio.loadSound( "alfa-romeo-c.mp3")
    audio.play(enginefx,{duration=1900})
    imghappy.isVisible = true
    img.isVisible = false

end
    end
local function reset()
    imghappy.isVisible = false
    img.isVisible = true
    end
imghappy:addEventListener( "touch", reset )
Runtime:addEventListener("accelerometer", acelerometro )
Runtime:addEventListener( "location", speedfunc )

Please help me i have to bring it to the teacher Monday

[roaminggamer]

Welcome to the community.

Please tell us what device you’re using.

There are a lot of factors that can affect accuracy of GPS (GPS.gov: GPS Accuracy).

You should print the:

• accuracy too: Solar2D Documentation — API Reference | Events | location | accuracy
• Error code (in case somthing is going wrong) Solar2D Documentation — API Reference | Events | location | errorCode
• sim time delta between events. - So you know how often the event is occuring. If this doesn’t update you aren’t getting position update.

Also, be sure you’re using the right build.settings: Solar2D Documentation — API Reference | Events | location

I would turn off: "android.permission.ACCESS_COARSE_LOCATION" ,

Oh, and don’t forget if you’ve disabled GPS and/or location services via settings on your phone, GPS probably won’t work.

Updates below to add timer-delta

-----------------------------------------------------------------------------------------
--
-- main.lua
--
-----------------------------------------------------------------------------------------
--SCRIPT POR KKRAFT PARA TRABALHO DE CIENCIAS!

local fundo = display.newImage("fundo.png")
local img = display.newImage("rosto.png")
local imghappy = display.newImage("rostohappy.png")
local timeLabel = display.newText( "waiting", 100, 100 )
local accuracyLabel = display.newText( "waiting", 100, 120 )
local errorLabel = display.newText( "waiting", 100, 140 )
local lastTime = 0;

--Inicio
fundo.width = 10000
fundo.height = 10000
img.width = 350
img.height = 300
imghappy.width = 350
imghappy.height = 300
imghappy.isVisible = false
img.x = display.contentCenterX - 5
img.y = display.contentCenterY
imghappy.x = display.contentCenterX - 5
imghappy.y = display.contentCenterY

--Vibração

local function acelerometro(event)
    if event.zGravity >= 0.1 or event.xGravity >= 0.1 then
    system.vibrate( )
end
end
local function speedfunc(event)
    print( event.speed )
    if event.speed >= 0.0001 then
    local enginefx = audio.loadSound( "alfa-romeo-c.mp3")
    audio.play(enginefx,{duration=1900})
    imghappy.isVisible = true
    img.isVisible = false

    -- Calculate delta time and update label
    local deltaTime = event.time - lastTime
    lastTime = event.time
    timeLabel.text = string.format( "delta = %d ", deltaTime )

    -- Update other labels
     errorLabel.text = event.errorCode and "Error Code: " .. event.errorCode or "No error code"
     accuracyLabel.text = event.accuracy and "Accuracy: " .. event.accuracy or "No accuracy value?"

end
    end
local function reset()
    imghappy.isVisible = false
    img.isVisible = true
    end
imghappy:addEventListener( "touch", reset )
Runtime:addEventListener("accelerometer", acelerometro )
Runtime:addEventListener( "location", speedfunc )

[roaminggamer]

Also, have you run the GPS example that comes with Corona simulator built-in ‘Samples’ on your phone?

If the sample app works and yours doesn’t you can compare the code to see what is different.

[Kkraft]

THANKS A LOT MAN, i ve trying that for almost 2 months, I understood that the error is the speed value is a string, so a added a tonumber and it works!(i just realized it cause you used string.format, so thanks dude you saved me)