Android application: Power monitor for Atorch

Welcome to my power monitor application for Atorch power meters! This app allows users to track and monitor their power usage in real-time, helping them to save energy and reduce their carbon footprint. With this app, users can view detailed statistics on their energy consumption. Whether you're looking to save money on your energy bills or simply want to be more energy-efficient, this app is the perfect tool for you.

Supported for Atorch UD18 UD24 DT24 and similar USB or S1-B mains power meters, that share the same BLE Serial protocol

Version	Development	Language	Platform	Screenshots
1.15	In-Progress	JavaScript	Android: Droidscript, Framework7

Source is available on GitHub repository

Using AI capabilities as was able to identify CRC for USB meter (device type 0x03) It works for device that i own.

FUNCTION verifyUSB(message: STRING) -> BOOLEAN
    # Convert hex string to byte array
    bytes = HEX_TO_BYTES(message)
    
    # Payload = bytes from index 2 to second-to-last
    payload = bytes[2 : LENGTH(bytes) - 1]
    
    # Accumulator: sum all payload bytes, keep only lowest 8 bits
    acc = 0
    FOR EACH byte IN payload:
        acc = (acc + byte) AND 0xFF
    
    # XOR accumulator with 0x44 to get expected checksum
    expected = acc XOR 0x44
    
    # Compare with last byte of message
    RETURN expected EQUALS bytes[LENGTH(bytes) - 1]
END FUNCTION

or as one liner

checksum = (SUM(bytes[2:-1]) AND 0xFF) XOR 0x44

I'm working on Javascript based environment and this code works for me for USB based device

function verifyChecksumUsb(message) {
  const bytes = new Uint8Array(message.length / 2);
  for (let i = 0; i < message.length; i += 2) {
    bytes[i / 2] = parseInt(message.substr(i, 2), 16);
  }
  const payload = bytes.slice(2, -1);
  const sum = payload.reduce((acc, v) => (acc + v) & 0xFF, 0);
  const checksum = (sum ^ 0x44) & 0xFF;
  return checksum === bytes[bytes.length - 1];
}
 
const msg = 'FF550103000383000080004EBA000027D7004B0147001F003312111E0000000000000072'
console.log('Checksum for '+ msg +' is ' + verifyChecksumUsb(msg))
// Checksum for FF550103000383000080004EBA000027D7004B0147001F003312111E0000000000000072 is true

PowerMon version 1.10

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Full changelog