How can I track when a player is moving at all, even on mobile?

I have a script but it only works for PC, and I want to be able to also do it on mobile, but they do not use keys and I'm pretty bad with UserInputService. Any advice?

--// Services
local repStr = game:GetService'ReplicatedStorage'
local UserInputService = game:GetService'UserInputService'

--// References
local plr = game.Players.LocalPlayer
repeat wait() until plr.Character
local char = plr.Character
local hum = char:WaitForChild'Humanoid'
local step = repStr:WaitForChild'step'

--// Variables
local timeElapsed
local lastStep = 0

KeyHeld = false
w = false
a = false
s = false
d = false

function onKeyPress(inputObject,gameProcessed)
    if inputObject.KeyCode == Enum.KeyCode.W then
        w = true
        KeyHeld = true
    elseif inputObject.KeyCode == Enum.KeyCode.A then
        a = true
        KeyHeld = true
    elseif inputObject.KeyCode == Enum.KeyCode.S then
        s = true
        KeyHeld = true
    elseif inputObject.KeyCode == Enum.KeyCode.D then
        d = true
        KeyHeld = true
    end
end

function onKeyRelease(inputObject,gameProcessed)
    if inputObject.KeyCode == Enum.KeyCode.W then
        w = false
        if a == false and s == false and d == false then
            KeyHeld = false
        end
elseif inputObject.KeyCode == Enum.KeyCode.A then
    a = false
    if w == false and s == false and d == false then
        KeyHeld = false
    end
        elseif inputObject.KeyCode == Enum.KeyCode.S then
            s = false
            if w == false and a == false and d == false then
                KeyHeld = false
            end
    elseif inputObject.KeyCode == Enum.KeyCode.D then
        d = false
        if w == false and a == false and s == false then
            KeyHeld = false
        end
    end
end

game:GetService("UserInputService").InputBegan:connect(onKeyPress)
game:GetService("UserInputService").InputEnded:connect(onKeyRelease)

while wait(.13) do
    if KeyHeld ~= false then
        wait(.13)
            local elapsed = tick()-lastStep
            lastStep = tick()
            if elapsed >= .13 then
                step:FireServer()
            end
    end
end