The Squirrel code to create an Electric Imp driven micro wifi analyzer. Presents connected state, signal RSSI value, roundtrip latency, and voltage. Great for remote signal detection and analysis.

wiflea.nut

// Code below this line is for your node.
// Drive 3.3v LCD Screen using a Sparkfun SerLCD backpack from an Electric IMP

hardware.uart12.configure(9600, 8, PARITY_NONE, 1, NO_RX);

CharactersInLCD     <- 16;

ConnectedState      <- false;
LastLatency         <- 0;

function BuildMessage() {
    local signal = ""+imp.rssi();
    while (signal.len() < 4) {
        signal = " "+signal;
    }
    local lat = ""+LastLatency+"ms";
    while (lat.len() < 6) {
        lat = lat+" ";
    }
    local voltage = ""+hardware.voltage()+"v";
    while (voltage.len() < 8) {
        voltage = " "+voltage;
    }
    local msg = (ConnectedState ? "ALIVE" : "DEAD ")+"  I "+signal+"dBm" + 
                lat+" I"+voltage;
    return msg;
}


class Led extends InputPort {
    name = "led";
    function set(prevTime) {
        local now = hardware.millis();
        ConnectedState = true;
        LastLatency = (now - prevTime);
    }
}

local ticktock = OutputPort("ticktock");

//Backlight brightness values from 128 to 157
//128 - Backlight off
//140 - 40% on
//150 - 73% on
//157 - 100% on
function LCDBacklight(Brightness)
{
    if((Brightness>127)&&(Brightness<158))
    {
        hardware.uart12.write(124);
        hardware.uart12.write(Brightness); 
    }
}

//Sets the SerLCD module to the correct LCD Type.
//3 - 20 Characters wide
//4 - 16 Characters wide
//5 - 4 Lines
//6 - 2 Lines
function SerLCDTypeSetup(LCDType)
{
    if((LCDType>3)||(LCDType<4)||(LCDType<5)||(LCDType<6))
    {
        hardware.uart12.write(124);
        hardware.uart12.write(LCDType); 
    }
}

//Sets the splash screen.
function LCDSetSplash(Message)
{
    LCDClear();
    hardware.uart12.write(Message);

    imp.sleep( 1 );
   
    hardware.uart12.write(0x7C);
    hardware.uart12.write(0x0A);
   
    imp.sleep( 1 );
}

//Splash screen on/off toggle
function LCDToggleSplash()
{
    hardware.uart12.write(0x7C);
    hardware.uart12.write(0x09);
}


function LCDClear()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x01);
    hardware.uart12.write(254);
    hardware.uart12.write(128);
    LCDBoxCursorOff();
}

function LCDMoveCursorRight()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x14);
}

function LCDMoveCursorLeft()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x10);
}

function LCDScrollRight()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x1c); 
}

function LCDScrollLeft()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x18); 
}

function LCDVisualDisplayOn()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x0C);
}

function LCDVisualDisplayOff()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x08);
}

function LCDUnderlineCursorOn()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x0E);
}

function LCDUnderlineCursorOff()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x0C);
}

function LCDBoxCursorOn()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x0D);
}

function LCDBoxCursorOff()
{
    hardware.uart12.write(254);
    hardware.uart12.write(0x0C);
}

// Position is zero based
function LCDSetCursorPosition(Line,Position)
{
    local LineBaseAddress = 0;
    if(CharactersInLCD==16)
    {
        if(Line==2)
        {
            LineBaseAddress = 64;
        }
         if(Line==3)
        {
            LineBaseAddress = 16;
        }
         if(Line==4)
        {
            LineBaseAddress = 80;
        }
    }
    if(CharactersInLCD==20)
    {
         if(Line==2)
        {
            LineBaseAddress = 64;
        }
         if(Line==3)
        {
            LineBaseAddress = 20;
        }
         if(Line==4)
        {
            LineBaseAddress = 84;
        }
    }
    hardware.uart12.write(254);
    hardware.uart12.write(LineBaseAddress + Position + 128);
}

function LCDWriteMessage(LCDMessage)
{
    hardware.uart12.write(LCDMessage);
}


function ping() {
    ConnectedState = false;
    ticktock.set(hardware.millis());
}

//Main Execution loop
function loop()
{

    // On every loop, display current status
    LCDClear(); 
    LCDWriteMessage(BuildMessage());
    
    // The sent up next status attempt ping
    imp.wakeup(0.5, ping);

    // Queue next loop execution
    imp.wakeup(1.0, loop);
}


//Setup Activities - only executed once
imp.configure("WiFlea", [Led()], [ticktock], {});

// Initial clear and set
LCDClear(); 
LCDWriteMessage(BuildMessage());


//Pause 2 Seconds before starting the main loop - adjust to taste
imp.wakeup(1.0, loop);