Init

scale.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"fmt"
+	"math"
+	"time"
+)
+
+func parseData(weightBytes []byte) *Weight {
+	ctrlByte := weightBytes[0]
+
+	isWeightRemoved := isBitSet(ctrlByte, 7)
+	isStabilized := isBitSet(ctrlByte, 5)
+	isLBSUnit := isBitSet(ctrlByte, 0)
+	isCattyUnit := isBitSet(ctrlByte, 4)
+
+	// fmt.Printf("IsWeightRemoved: %v\n", isWeightRemoved)
+	// fmt.Printf("6 LSB Unknown: %v\n", isBitSet(ctrlByte, 6))
+	// fmt.Printf("IsStabilized: %v\n", isStabilized)
+	// fmt.Printf("IsCattyOrKg: %v\n", isCattyUnit)
+	// fmt.Printf("3 LSB Unknown: %v\n", isBitSet(ctrlByte, 3))
+	// fmt.Printf("2 LSB Unknown: %v\n", isBitSet(ctrlByte, 2))
+	// fmt.Printf("1 LSB Unknown: %v\n", isBitSet(ctrlByte, 1))
+	// fmt.Printf("IsLBS: %v\n", isLBSUnit)
+
+	// // Only if the value is stabilized and the weight is *not* removed, the date is valid
+	if isStabilized && !isWeightRemoved {
+		wb4 := int(weightBytes[4])
+		wb3 := int(weightBytes[3])
+		year := (wb4<<8 | wb3)
+		month := int(weightBytes[5])
+		day := int(weightBytes[6])
+		hours := int(weightBytes[7])
+		min := int(weightBytes[8])
+		sec := int(weightBytes[9])
+
+		// Is the year plausible? Check if the year is in the range of 20 years...
+		now := time.Now()
+		if math.Abs(float64(now.Year()-year)) > 20 || year > now.Year() {
+			return nil
+		}
+
+		wb1 := int(weightBytes[1])
+		wb2 := int(weightBytes[2])
+		weightVal := 0.0
+		if isLBSUnit || isCattyUnit {
+			weightVal = float64(((wb2)<<8)|(wb1)) / 100.0
+		} else {
+			weightVal = float64(((wb2)<<8)|(wb1)) / 200.0
+		}
+
+		t := time.Date(year, time.Month(month), day, hours, min, sec, 0, time.Local)
+		weight := &Weight{Weight: weightVal, Time: t}
+
+		// fmt.Printf("Payload is: %#x\n", weightBytes)
+		fmt.Printf("[+] Year: %v, Month: %v, day: %v, hr: %v, min: %v, sec: %v = %v \n", year, month, day, hours, min, sec, weightVal)
+		return weight
+	}
+	return nil
+}
+
+func isBitSet(value byte, bit uint) bool {
+	return (value & (1 << bit)) != 0
+}