A simple javascript checksum calculator for HITACHI AC Remote: R-LT0541-HTA/Y.K.1.1-1 V2.3

hitachi_AC_checksum_calculator.js

function hex2bin(hex){
    return ("00000000" + (parseInt(hex, 16)).toString(2)).substr(-8);
}

function checksum(bytes){
  bytes = bytes.match(/.{1,2}/g);
  let removed = bytes.splice(0,5);

  var s = 0;
  
  bytes.forEach(function(hexByte){
    hex2bin(hexByte).match(/.{1,4}/g).forEach(function(halfByte){
      s+= parseInt(halfByte.split('').reverse().join(''),2)
    })
  })
  
  bytes.push(parseInt(hex2bin(s.toString(16)).split('').reverse().join(''), 2).toString(16).toUpperCase());
  
  return removed.join('') + bytes.join('');
}

console.log(checksum("B2AE4D91F061C80000000010"));