Merge pull request #3 from linspb/Mettler_Toledo

Thanks for the pull request!

50-usb-scale.rules

@@ -1,3 +1,4 @@
 SUBSYSTEM=="usb", ATTR{idVendor}=="1446", ATTR{idProduct}=="6a73", MODE="0776"
 SUBSYSTEM=="usb", ATTR{idVendor}=="7b7c", ATTR{idProduct}=="0100", MODE="0776"
 SUBSYSTEM=="usb", ATTR{idVendor}=="2474", ATTR{idProduct}=="0550", MODE="0776"
+SUBSYSTEM=="usb", ATTR{idVendor}=="0eb8", ATTR{idProduct}=="f000", MODE="0776"

scales.h

@@ -12,7 +12,12 @@
 //
 // **NSCALES** should be kept updated with the length of the list.
 //
-#define NSCALES 3
+#define NSCALES 4
+
+//
+// What is the number of the weighing result to show, as the first result may be incorrect (from the previous weighing)
+//
+#define WEIGH_COUNT 2
 
 //
 // Scales
@@ -24,5 +29,7 @@ uint16_t scales[NSCALES][2] = {\
     // USPS (Elane) PS311 "XM Elane Elane UParcel 30lb"
     {0x7b7c, 0x0100},
     // Stamps.com Stainless Steel 5 lb. Digital Scale
-    {0x2474, 0x0550}
+    {0x2474, 0x0550},
+    // Mettler Toledo
+    {0x0eb8, 0xf000}
 };

usbscale.c

@@ -94,6 +94,8 @@ int main(void)
     libusb_device* dev;
     libusb_device_handle* handle;
 
+    int weigh_count = WEIGH_COUNT -1;
+
     //
     // We first try to init libusb.
     //
@@ -213,9 +215,12 @@ int main(void)
                 printf("%x\n", data[i]);
             }
 #endif
-            scale_result = print_scale_data(data);
-            if(scale_result != 1)
-                break;
+            if (weigh_count < 1) {
+                scale_result = print_scale_data(data);
+                if(scale_result != 1)
+                   break;
+            }
+            weigh_count--;
         }
         else {
             fprintf(stderr, "Error in USB transfer\n");
@@ -275,13 +280,17 @@ static int print_scale_data(unsigned char* dat) {
     double weight = (double)(dat[4] + (dat[5] << 8)) / 10;
 
     if(expt != 255 && expt != 0) {
-        weight = pow(weight, expt);
+	if (expt > 127) {
+	    weight = weight * pow(10, expt-255);
+	} else {
+	    weight = pow(weight, expt);
+	}
     }
 
     //
     // The scale's first byte, its "report", is always 3.
     //
-    if(report != 0x03) {
+    if(report != 0x03 && report != 0x04) {
         fprintf(stderr, "Error reading scale data\n");
         return -1;
     }