TI-Nspire & BLE / Tiny BLE-Connection-Listener / SensorTag

The connection flow is as follows:

1. The ble.addStateListener() function registers a listener-callback.
2. The bleCentral.startScanning() function gets a scanner-callback to scan peripherals.
3. The connect() function gets a connector-callback to connect a found peripheral.

.lua

-- Tiny BLE-Connection-Listener for TI-Nspire
-- Tap the right half of the screen to start scanning.
-- Tap the left half of the screen to stop scanning.
require "bleCentral" require "color"

local myPeripheral = nil
local MESSAGES     = {}

function on.resize()
   W, H = platform.window:width(), platform.window:height()
   fontSize   = W/20
   lineSpace  = H/11
   leftMargin = W/50
   refreshMenu()
   platform.window:invalidate()
end
function on.construction()
   ble.addStateListener(listenerCallback)
end
function on.paint(gc)
   gc:setFont("sansserif", "r", fontSize)
   for i, v in ipairs(MESSAGES) do
      gc:drawString(v, leftMargin, (i - 1) * lineSpace)
   end
end

------------------------------
-- Define listener callback --
------------------------------
function listenerCallback(state)
   MESSAGES[1] = "Listener Callback"
   MESSAGES[2] = "   state: "..(state or "none")
   platform.window:invalidate()
end

----------------------------
-- Start or Stop scanning --
----------------------------
function peripheralOn()
   bleCentral.startScanning(scannerCallback)
   platform.window:invalidate()
end
function peripheralOff()
   bleCentral.stopScanning()
   if myPeripheral then
      myPeripheral:disconnect()
      MESSAGES[4] = "   peri name: " ..(myPeripheral:getName()  or "none")
      MESSAGES[5] = "   peri state: "..(myPeripheral:getState() or "none")
   end
   platform.window:invalidate()
end

-----------------------------
-- Define scanner callback --
-----------------------------
function scannerCallback(peripheral, advertisementData, isConnectable, RSSI)
   if peripheral then
      peripheral:connect(connectorCallback)
      MESSAGES[3] = "Scanner Callback"
      MESSAGES[4] = "   peri name: " ..(peripheral:getName()  or "none")
      MESSAGES[5] = "   peri state: "..(peripheral:getState() or "none")
      MESSAGES[6] = "   RSSI: "      ..(RSSI                  or "none").." dbm"
   end
   platform.window:invalidate()
end

-------------------------------
-- Define connector callback --
-------------------------------
function connectorCallback(peripheral, event)
   if peripheral then
      bleCentral.stopScanning()
      myPeripheral = peripheral
   end
   MESSAGES[7]  = "Connector Callback"
   MESSAGES[8]  = "   peri name: " ..(peripheral:getName()  or "none")
   MESSAGES[9]  = "   peri state: "..(peripheral:getState() or "none")
   MESSAGES[10] = "   event: "     ..(event                 or "none")
   platform.window:invalidate()
end

------------------
-- Menu & Mouse --
------------------
function refreshMenu()
   Menu = {
      {"Controls",
         {"Scan and Connect", function() peripheralOn()  end},
         {"Disconnect"      , function() peripheralOff() end},
      },
   }
   toolpalette.register(Menu)
end
function on.mouseUp(x, _)
   if x > W/2 then peripheralOn()  end
   if x < W/2 then peripheralOff() end
end