Teensy, tiny, Electric IMP Wifi SD card teams up with the Teensy 3.

// Send Network Time
// Configure the time zone as UTC (Coordinated Universal Time) time offset.
// Some examples:
//      Eastern Time Zone (New York)    -5
//      Central Time Zone (Chicago)     -6
//      Mountain Time Zone (Phoenix)    -7
//      Pacific Time Zone (Los Angeles) -8
//
// Generally for the US, Daylight Savings Time (DST) starts on the 2nd Sunday
// in March and ends on the 1st Sunday in November at 2:00 am local time.
// This event causes the clock to "Spring" forward in March; from 1:59:59
// => 3:00:00 (23 hour day). The clock will "Fall" back in November; from
// 1:59:59 => 1:00:00 (25 hour day). For the purpose of this program, DST is
// simply set to "1" when it's in effect, and "0" when it's not. 
//----------------------------------------------------------------------------

local TIMEZONE = -5;                        // US Eastern Time
local DST = 0;                              // Daylight Savings Time is false

// Variables for time storage
local pm, colon = false;                    // PM indicator and blinking colon HH:MM
local t, d;                                 // Time and date variables
local minute = 60, second = 60;             // Illegal values so display updates 1st time thru


// Variable to represent LED state
ledState <- 0;
 
// Variable to represent LED inhibit state
inhibit <- 0;


// Setup a serial port using default Sparkfun setting of 9600N81
local serialcomm = hardware.uart12;            // PIN1 = Tx; PIN2 = Rx
serialcomm.configure(9600, 8, PARITY_NONE, 1, NO_CTSRTS);


// Function called once every second
function Send_Time_Date() {


    while ((t = time()) == second);         // Synchronize seconds
    second = t; // GMT secs
    d = date(t + ((TIMEZONE + DST) * 60 * 60), 1); // from local time to GMT secs
    if (d.min != minute) {                  // Update time once every minute
     //server.log(format("Sync Time OK "));   
     //server.log(format(" minute = %d", minute));
     //server.log(format(" t = %d", t));
     //server.log(format(" d = %d", t));     
     serialcomm.write("T"+t); // Unix GMT UTC seconds     
     blink(); // toggles LED on IMP breakout once a minute
     minute = d.min;        //  updated
    }

   

//    server.show(format("WiFi %d dBm", imp.rssi()));

    // Schedule the next update
    imp.wakeup(0.90, Send_Time_Date);            // Not a whole lot to do here
}


// blink function called on Network time update
function blink()
{
    // Check if we've been switched off
    if(inhibit)
    {
        // Blinking inhibited, turn off the LED
        hardware.pin8.write(0);
    }
    else
    {
        // Change state
        ledState = ledState?0:1;
 
        // Reflect state to the pin
        hardware.pin8.write(ledState);
 
        // Schedule the next state change
        //imp.wakeup(0.1, blink);
    }
}

// input class for LED control channel
class input extends InputPort
{
  name = "LED control"
  type = "number"
 
  function set(value)
  {
      if(value == 0)
      {
          // 0 = Inhibit LED operation
          inhibit = 1;
      }
      else
      {
          // 1 = Enable LED operation
          inhibit = 0;
          blink();
      }
  }
}


// Configure pin 8 as an open drain output with internal pull up
hardware.pin8.configure(DIGITAL_OUT_OD_PULLUP);

// Register with the server
imp.configure("Network Time Clock Master R1", [], []);

// Display all the geeky details (in log window tab)
server.log(format("impeeID %s", hardware.getimpeeid()));
server.log(format("Voltage %f", hardware.voltage()));
server.log(format("MAC address %s", imp.getmacaddress()));
server.log(format("WiFi %d dBm", imp.rssi()));


// Send serial time / date
Send_Time_Date();