diff --git a/pylgbst/constants.py b/pylgbst/constants.py
index 0ba66c3..1fd5f7d 100644
--- a/pylgbst/constants.py
+++ b/pylgbst/constants.py
@@ -10,14 +10,18 @@ else:
 queue = queue  # just to use it
 
 
-def str2hex(data):  # TODO: eliminate it
+def str2hex(data):
     return binascii.hexlify(data).decode("utf8")
 
 
-def get_byte(seq, index):
+def usbyte(seq, index):
     return struct.unpack("<B", seq[index:index + 1])[0]
 
 
+def ushort(seq, index):
+    return struct.unpack("<H", seq[index:index + 2])[0]
+
+
 # GENERAL
 MOVE_HUB_HARDWARE_HANDLE = 0x0E
 MOVE_HUB_HARDWARE_UUID = '00001624-1212-efde-1623-785feabcd123'
diff --git a/pylgbst/movehub.py b/pylgbst/movehub.py
index 8e5b8c7..f20ac4d 100644
--- a/pylgbst/movehub.py
+++ b/pylgbst/movehub.py
@@ -84,7 +84,7 @@ class MoveHub(object):
         data = data[3:]
         log.debug("Notification on %s: %s", handle, str2hex(orig))
 
-        msg_type = get_byte(data, 2)
+        msg_type = usbyte(data, 2)
 
         if msg_type == MSG_PORT_INFO:
             self._handle_port_info(data)
@@ -93,7 +93,7 @@ class MoveHub(object):
         elif msg_type == MSG_SENSOR_DATA:
             self._handle_sensor_data(data)
         elif msg_type == MSG_SENSOR_SUBSCRIBE_ACK:
-            port = get_byte(data, 3)
+            port = usbyte(data, 3)
             log.debug("Sensor subscribe ack on port %s", PORTS[port])
             self.devices[port].finished()
         elif msg_type == MSG_PORT_CMD_ERROR:
@@ -107,13 +107,13 @@ class MoveHub(object):
             log.warning("Unhandled msg type 0x%x: %s", msg_type, str2hex(orig))
 
     def _handle_device_info(self, data):
-        if get_byte(data, 3) == 2:
+        if usbyte(data, 3) == 2:
             self.button.handle_port_data(data)
         else:
             log.warning("Unhandled device info: %s", str2hex(data))
 
     def _handle_sensor_data(self, data):
-        port = get_byte(data, 3)
+        port = usbyte(data, 3)
         if port not in self.devices:
             log.warning("Notification on port with no device: %s", PORTS[port])
             return
@@ -122,8 +122,8 @@ class MoveHub(object):
         device.queue_port_data(data)
 
     def _handle_port_status(self, data):
-        port = get_byte(data, 3)
-        status = get_byte(data, 4)
+        port = usbyte(data, 3)
+        status = usbyte(data, 4)
 
         if status == STATUS_STARTED:
             self.devices[port].started()
@@ -135,14 +135,14 @@ class MoveHub(object):
             log.warning("Unhandled status value: 0x%x", status)
 
     def _handle_port_info(self, data):
-        port = get_byte(data, 3)
-        status = get_byte(data, 4)
+        port = usbyte(data, 3)
+        status = usbyte(data, 4)
 
         if status == self.DEV_STATUS_DETACHED:
             log.info("Detached %s", self.devices[port])
             self.devices[port] = None
         elif status == self.DEV_STATUS_DEVICE or status == self.DEV_STATUS_GROUP:
-            dev_type = get_byte(data, 5)
+            dev_type = usbyte(data, 5)
             self._attach_device(dev_type, port)
         else:
             raise ValueError("Unhandled device status: %s", status)
diff --git a/pylgbst/peripherals.py b/pylgbst/peripherals.py
index 6db1634..6bd6bfb 100644
--- a/pylgbst/peripherals.py
+++ b/pylgbst/peripherals.py
@@ -167,8 +167,6 @@ class EncodedMotor(Peripheral):
             relative = 1
 
         absolute = round(relative * 100)  # scale of 100 is proven by experiments
-        if absolute < 0:
-            absolute += 255
         return int(absolute)
 
     def _wrap_and_write(self, mtype, params, speed_primary, speed_secondary):
@@ -177,9 +175,9 @@ class EncodedMotor(Peripheral):
 
         params = pack("<B", self.MOVEMENT_TYPE) + pack("<B", mtype) + params
 
-        params += pack("<B", self._speed_abs(speed_primary))
+        params += pack("<b", self._speed_abs(speed_primary))
         if self.port == PORT_AB:
-            params += pack("<B", self._speed_abs(speed_secondary))
+            params += pack("<b", self._speed_abs(speed_secondary))
 
         params += self.TRAILER
 
@@ -235,7 +233,7 @@ class EncodedMotor(Peripheral):
             self._notify_subscribers(rotation)
         elif self._port_subscription_mode == self.SENSOR_SOMETHING1:
             # TODO: understand what it means
-            rotation = unpack("<B", data[4])[0]
+            rotation = usbyte(data, 4)
             self._notify_subscribers(rotation)
         elif self._port_subscription_mode == self.SENSOR_SPEED:
             rotation = unpack("<b", data[4])[0]
@@ -289,22 +287,22 @@ class TiltSensor(Peripheral):
 
     def handle_port_data(self, data):
         if self._port_subscription_mode == self.MODE_3AXIS_SIMPLE:
-            state = unpack("<B", data[4:5])[0]
+            state = usbyte(data, 4)
             self._notify_subscribers(state)
         elif self._port_subscription_mode == self.MODE_2AXIS_SIMPLE:
-            state = unpack("<B", data[4:5])[0]
+            state = usbyte(data, 4)
             self._notify_subscribers(state)
         elif self._port_subscription_mode == self.MODE_BUMP_COUNT:
-            bump_count = unpack("<H", data[4:6])[0]
+            bump_count = ushort(data, 4)
             self._notify_subscribers(bump_count)
         elif self._port_subscription_mode == self.MODE_2AXIS_FULL:
-            roll = self._byte2deg(unpack("<B", data[4:5])[0])
-            pitch = self._byte2deg(unpack("<B", data[5:6])[0])
+            roll = self._byte2deg(usbyte(data, 4))
+            pitch = self._byte2deg(usbyte(data, 5))
             self._notify_subscribers(roll, pitch)
         elif self._port_subscription_mode == self.MODE_3AXIS_FULL:
-            roll = self._byte2deg(unpack("<B", data[4:5])[0])
-            pitch = self._byte2deg(unpack("<B", data[5:6])[0])
-            yaw = self._byte2deg(unpack("<B", data[6:7])[0])  # did I get the order right?
+            roll = self._byte2deg(usbyte(data, 4))
+            pitch = self._byte2deg(usbyte(data, 5))
+            yaw = self._byte2deg(usbyte(data, 6))  # did I get the order right?
             self._notify_subscribers(roll, pitch, yaw)
         else:
             log.debug("Got tilt sensor data while in unexpected mode: %s", self._port_subscription_mode)
@@ -337,23 +335,23 @@ class ColorDistanceSensor(Peripheral):
 
     def handle_port_data(self, data):
         if self._port_subscription_mode == self.COLOR_DISTANCE_FLOAT:
-            color = unpack("<B", data[4:5])[0]
-            distance = unpack("<B", data[5:6])[0]
-            partial = unpack("<B", data[7:8])[0]
+            color = usbyte(data, 4)
+            distance = usbyte(data, 5)
+            partial = usbyte(data, 7)
             if partial:
                 distance += 1.0 / partial
             self._notify_subscribers(color, float(distance))
         elif self._port_subscription_mode == self.COLOR_ONLY:
-            color = unpack("<B", data[4:5])[0]
+            color = usbyte(data, 4)
             self._notify_subscribers(color)
         elif self._port_subscription_mode == self.DISTANCE_INCHES:
-            distance = unpack("<B", data[4:5])[0]
+            distance = usbyte(data, 4)
             self._notify_subscribers(distance)
         elif self._port_subscription_mode == self.DISTANCE_HOW_CLOSE:
-            distance = unpack("<B", data[4:5])[0]
+            distance = usbyte(data, 4)
             self._notify_subscribers(distance)
         elif self._port_subscription_mode == self.DISTANCE_SUBINCH_HOW_CLOSE:
-            distance = unpack("<B", data[4:5])[0]
+            distance = usbyte(data, 4)
             self._notify_subscribers(distance)
         elif self._port_subscription_mode == self.OFF1 or self._port_subscription_mode == self.OFF2:
             log.info("Turned off led on %s", self)
@@ -362,12 +360,12 @@ class ColorDistanceSensor(Peripheral):
             self._notify_subscribers(count)
         elif self._port_subscription_mode == self.STREAM_3_VALUES:
             # TODO: understand better meaning of these 3 values
-            val1 = unpack("<H", data[4:6])[0]
-            val2 = unpack("<H", data[6:8])[0]
-            val3 = unpack("<H", data[8:10])[0]
+            val1 = ushort(data, 4)
+            val2 = ushort(data, 6)
+            val3 = ushort(data, 8)
             self._notify_subscribers(val1, val2, val3)
         elif self._port_subscription_mode == self.LUMINOSITY:
-            luminosity = unpack("<H", data[4:6])[0] / 1023.0
+            luminosity = ushort(data, 4) / 1023.0
             self._notify_subscribers(luminosity)
         else:  # TODO: support whatever we forgot
             log.debug("Unhandled data in mode %s: %s", self._port_subscription_mode, str2hex(data))
@@ -390,7 +388,7 @@ class Voltage(Peripheral):
     # good 7.5v ~= 3892
     # liion 5v ~= 2100
     def handle_port_data(self, data):
-        val = unpack("<H", data[4:6])[0]
+        val = ushort(data, 4)
         self.last_value = val / 4096.0
         if self.last_value < 0.2:
             logging.warning("Battery low! %s%%", int(100 * self.last_value))
@@ -409,7 +407,7 @@ class Amperage(Peripheral):
         super(Amperage, self).subscribe(callback, mode, granularity)
 
     def handle_port_data(self, data):
-        val = unpack("<H", data[4:6])[0]
+        val = ushort(data, 4)
         self.last_value = val / 4096.0
         self._notify_subscribers(self.last_value)
 
@@ -440,7 +438,7 @@ class Button(Peripheral):
             self.parent.connection.write(MOVE_HUB_HARDWARE_HANDLE, pack("<B", len(cmd) + 1) + cmd)
 
     def handle_port_data(self, data):
-        param = unpack("<B", data[5:6])[0]
+        param = usbyte(data, 5)
         if self.in_progress():
             self.finished()
         self._notify_subscribers(bool(param))