fsr402.ino

#include <SPI.h>
#include <SD.h>

const int chipSelect = 4;
const double R1 = 10;

void setup() {
  Serial.begin(9600);
  while (!Serial) {
    ;
  }


  Serial.print("Initializing SD card...");

  if (!SD.begin(chipSelect)) {
    Serial.println("Card failed, or not present");
    return;
  }
  Serial.println("card initialized.");
}

void loop() {
  // 変数の宣言
  double Vo, Rf, fg, kg;
  int ain = analogRead(1);
  // アナログ入力値から出力電圧を計算
  Vo = ain * 5.0 / 1024;
  // 出力電圧からFRSの抵抗値を計算
  Rf = R1*Vo / (5.0 - Vo);
  // FRSの抵抗値から圧力センサの荷重を計算
  fg = 880.79/Rf + 47.96;
  kg = (fg / 4448) * 10;

  File dataFile = SD.open("DATALOG.TXT", FILE_WRITE);
  if (dataFile) {
    dataFile.println(kg);
    dataFile.close();
    Serial.println(kg);
  } else {
    Serial.println("error opening datalog.txt");
  }

  delay(1000);
}

post.lua

file, msg = io.open("DATALOG.TXT", "r")

if file then
    data = file:read("*a")

    t = {}
    for line in string.gmatch(data, "(.-)\n") do
        table.insert(t, string.sub(line, 1, #line))
    end

    latest = t[table.maxn(t)]
    if latest == "" then
        return
    end

    boundary = "--61141483716826"
    contentType = "multipart/form-data; boundary=" .. boundary

    token = "**************************************"
    local ENDPOINT_URL = "https://slack.com/api/chat.postMessage?token=" .. token .. "&channel=%23toybox&text=" .. latest .. "kg&as_user=true&link_names=channel"

    b, c, h = fa.request {
        url = ENDPOINT_URL,
        headers = {
            ["Content-Type"] = contentType
        }
    }

    print(b)
    print(c)
    print(h)
else
    print(msg)
end