bleOnSTM

func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {
        let stringValue = String(bytes: characteristic.value!, encoding: .utf8)
        print("update \(stringValue) errot \(error?.localizedDescription)")
        let on = "\u{01}\u{01}"
        let of = "\u{00}\u{00}"
        if let data = of.data(using: .utf8) {
            stm?.writeValue(data, for: characteristic, type: .withoutResponse)
        }
    }