Wifi Scanner with ESP8266 + TFT ST7735B (NodeMCU)

user.lua

-- Tested with
-- NodeMCU 3.0.0.0 built on nodemcu-build.com provided by frightanic.com
--	branch: release
--	commit: d4ae3c364bd8ae3ded8b77d35745b7f07879f5f9
--	release: 
--	release DTS: 202105102018
--	SSL: false
--	build type: float
--	LFS: 0x0 bytes total capacity
--	modules: bit,file,gpio,net,node,spi,tmr,uart,ucg,wifi
-- build 2021-11-22 17:49 powered by 
-- Lua 5.1.4 on SDK 3.0.1-dev(fce080e)
-- setup SPI and connect display
function init_spi_display()
    -- Hardware SPI CLK  = GPIO14
    -- Hardware SPI MOSI = GPIO13
    -- Hardware SPI MISO = GPIO12 (not used)
    -- Hardware SPI /CS  = GPIO15 (not used)
    -- CS, D/C, and RES can be assigned freely to available GPIOs
    local cs  = 8 -- GPIO15, pull-down 10k to GND
    local dc  = 4 -- GPIO2
    local res = 0 -- GPIO16
    local bus = 1

    spi.setup(bus, spi.MASTER, spi.CPOL_LOW, spi.CPHA_LOW, 8, 8)
    -- we won't be using the HSPI /CS line, so disable it again
    gpio.mode(8, gpio.INPUT, gpio.PULLUP)

    disp = ucg.st7735_18x128x160_hw_spi(bus, cs, dc, res)
end

function calculateSignalLevel(rssi, numLevels)
    local MIN_RSSI = -100
    local MAX_RSSI = -55 
    if rssi <= MIN_RSSI then
        return 0
    elseif rssi >= MAX_RSSI then
        return numLevels - 1
    else 
      local inputRange = (MAX_RSSI - MIN_RSSI)
      local outputRange = (numLevels - 1)
      return (rssi - MIN_RSSI) * outputRange / inputRange
    end
end

function extractWifiData(k, line)
    local wd = {}
    wd["ssid"] = k
    wd["authmode"], rssi, wd["bssid"], wd["channel"] = string.match(line, "([^,]+),([^,]+),([^,]+),([^,]+)")
    wd["rssi"] = tonumber(rssi)
    wd["level"] = calculateSignalLevel(wd["rssi"], 4)
    wd["age"] = 1
    return wd
end

function updateWifiData(oldData, line)
    local wd = extractWifiData("",line)
    oldData["age"]  = oldData["age"] - 1
    oldData["rssi"] = wd["rssi"]
    oldData["level"] = wd["level"]
    oldData["channel"] = wd["channel"]
    return oldData 
end

function filter(t, filterIter)
  local out = {}

  for k, v in pairs(t) do
    if filterIter(k, v) then out[k] = v end
  end

  return out
end

function updateWifiTable(t)
    for k,v in pairs(wifidata) do
        v["age"] = v["age"] + 1
    end
    
    for k,v in pairs(t) do
        if wifidata[k] then
            wifidata[k] = updateWifiData(wifidata[k], v)
        else
            wifidata[k] = extractWifiData(k, v)
        end
    end

    wifidata = filter(wifidata, function(k, v) return v["age"] < 10 end)
end

function drawIndicator(fillIndicator, fillBlue, x, y, w, h) 
    if fillIndicator then
      if fillBlue then 
        disp:setColor(79, 122, 240) -- a blue color
      else
        disp:setColor(31, 240, 87)  -- a green color
      end
      disp:drawBox(x, y-h, w, h)
    else
      disp:setColor(0, 0, 0)
      disp:drawBox(x+1, y-h+1, w-2, h-2)
      disp:setColor(80, 80, 80)
      disp:drawFrame(x, y-h, w, h)
    end
end

function printWifiLine(y, h, data)
    if data["ssid"] == nil then
        disp:setClipRange(0, y-h, 160, h)
        disp:setColor(0, 0, 0)
        disp:drawBox(0, y-h, 160, h)
        disp:undoClipRange()
    else
        disp:setClipRange(0, y-h, 138, h)
        disp:setColor(0, 0, 0)
        disp:drawBox(0, y-h, 138, h)

        disp:setClipRange(0, y-h, 125, h)
        disp:setPrintPos(0,y)
        disp:setColor(255, 255, 255)
        disp:print(data["ssid"])
        disp:undoClipRange()

        local w = disp:getStrWidth(data["channel"])
        disp:setClipRange(138-w-4, y-h, w+4, h)
        disp:setPrintPos(138-w,y)
        disp:print(data["channel"])
        disp:undoClipRange()

        drawIndicator(data["level"] >= 0, data["authmode"] == 0, 140, y, 4, 3)
        drawIndicator(data["level"] >= 1, data["authmode"] == 0, 145, y, 4, 5)
        drawIndicator(data["level"] >= 2, data["authmode"] == 0, 150, y, 4, 7)
        drawIndicator(data["level"] >= 3, data["authmode"] == 0, 155, y, 4, 9)
    end
end

function updateDispData(dispdata, data) 
    local changed = false
    for i,key in ipairs({"ssid", "level", "authmode", "channel"}) do 
        if dispdata[key] ~= data[key] then
            changed = true
            dispdata[key] = data[key]
        end
    end
    return changed    
end

function loop()
  wifi.sta.getap(updateWifiTable)
  local lineHeight = 12
  local curRow = lineHeight
  
  local alines = {}
  for k,v in pairs(wifidata) do
    table.insert(alines, v) 
  end

  if table.getn(alines) > 1 then
    table.sort(alines, function(a,b) return a["rssi"] > b["rssi"] or (a["rssi"] == b["rssi"] and a["ssid"] < b["ssid"]) end)
  end
  for i=1,9 do table.insert(alines, {ssid=nil}) end
  
  for i,v in ipairs(alines) do
     if i > 9 then 
        break 
     end    
     curRow = curRow + lineHeight

     if updateDispData(dispdata[i], v) then
        printWifiLine(curRow, lineHeight, dispdata[i])
     end
  end
end

wifidata = {}
dispdata = {}
for i=1,9 do dispdata[i] = {} end

init_spi_display()
disp:begin(ucg.FONT_MODE_TRANSPARENT)
disp:setFont(ucg.font_helvB08_hr)
disp:setRotate270()

disp:setColor(255, 255, 255)
disp:setPrintDir(0)
disp:clearScreen()
disp:setColor(255, 255, 255)

local str = "== WIFI SCANNER =="
disp:setPrintPos((160 - disp:getStrWidth(str))/2,12)
disp:print(str)

wifi.setmode(wifi.STATION)

loop()
tmr.create():alarm(5000, tmr.ALARM_AUTO, function() loop() end)

Rev 2 is compatible with NodeMCU 3.0.0.0 powered by Lua 5.1.4 on SDK 3.0.1-dev(fce080e), required modules are: bit,file,gpio,net,node,spi,tmr,uart,ucg,wifi