diff --git a/bumblebee/modules/battery.py b/bumblebee/modules/battery.py
index a22c8d8..5d00768 100644
--- a/bumblebee/modules/battery.py
+++ b/bumblebee/modules/battery.py
@@ -6,7 +6,7 @@ Parameters:
     * battery.device     : Comma-separated list of battery devices to read information from (defaults to auto for auto-detection)
     * battery.warning    : Warning threshold in % of remaining charge (defaults to 20)
     * battery.critical   : Critical threshold in % of remaining charge (defaults to 10)
-    * battery.showdevice : If set to "true", add the device name to the widget
+    * battery.showdevice : If set to "true", add the device name to the widget (defaults to False)
 """
 
 import os
@@ -15,6 +15,7 @@ import glob
 import bumblebee.input
 import bumblebee.output
 import bumblebee.engine
+import bumblebee.util
 
 class Module(bumblebee.engine.Module):
     def __init__(self, engine, config):
@@ -57,7 +58,7 @@ class Module(bumblebee.engine.Module):
             return "n/a"
         capacity = capacity if capacity < 100 else 100
         widget.set("capacity", capacity)
-        if self.parameter("showdevice") == "true":
+        if bumblebee.util.asbool(self.parameter("showdevice", False)):
             widget.set("theme.minwidth", "100% ({})".format(os.path.basename(widget.name)))
             return "{}% ({})".format(capacity, os.path.basename(widget.name))
         widget.set("theme.minwidth", "100%")
diff --git a/bumblebee/modules/disk.py b/bumblebee/modules/disk.py
index 0ed4895..e679794 100644
--- a/bumblebee/modules/disk.py
+++ b/bumblebee/modules/disk.py
@@ -17,6 +17,7 @@ import os
 import bumblebee.input
 import bumblebee.output
 import bumblebee.engine
+import bumblebee.util
 
 class Module(bumblebee.engine.Module):
     def __init__(self, engine, config):
@@ -24,9 +25,9 @@ class Module(bumblebee.engine.Module):
             bumblebee.output.Widget(full_text=self.diskspace)
         )
         self._path = self.parameter("path", "/")
-        self._sused = self.parameter("showUsed", "yes")
-        self._ssize = self.parameter("showSize", "yes")
-        self._spercent = self.parameter("showPercent", "yes")
+        self._sused = bumblebee.util.asbool(self.parameter("showUsed", True))
+        self._ssize = bumblebee.util.asbool(self.parameter("showSize", True))
+        self._spercent = bumblebee.util.asbool(self.parameter("showPercent", True))
         self._app = self.parameter("open", "xdg-open")
         self._perc = 0
         self._used = 0
@@ -37,19 +38,19 @@ class Module(bumblebee.engine.Module):
                                                           self._path))
 
     def diskspace(self, widget):
-        if self._sused == "yes":
+        if self._sused:
             used_str = bumblebee.util.bytefmt(self._used)
         else:
             used_str = ""
-        if self._ssize == "yes":
+        if self._ssize:
             size_str = bumblebee.util.bytefmt(self._size)
         else:
             size_str = ""
-        if self._spercent == "yes":
+        if self._spercent:
             percent_str = self._perc
         else:
             percent_str = ""
-        if self._sused != "yes" or self._ssize != "yes":
+        if not self._sused or not self._ssize:
             separator = ""
         else:
             separator = "/"
diff --git a/bumblebee/modules/memory.py b/bumblebee/modules/memory.py
index 9f38624..42816b9 100644
--- a/bumblebee/modules/memory.py
+++ b/bumblebee/modules/memory.py
@@ -5,7 +5,7 @@
 Parameters:
     * memory.warning : Warning threshold in % of memory used (defaults to 80%)
     * memory.critical: Critical threshold in % of memory used (defaults to 90%)
-    * memory.usedonly: Only show the amount of RAM in use.
+    * memory.usedonly: Only show the amount of RAM in use (defaults to False).
 """
 
 try:
@@ -29,7 +29,7 @@ class Module(bumblebee.engine.Module):
 
     def memory_usage(self, widget):
         used = self._mem.total - self._mem.available
-        if bool(self.parameter("usedonly", 0)) == 1:
+        if bumblebee.util.asbool(self.parameter("usedonly", False)):
             return bumblebee.util.bytefmt(used)
         return "{}/{} ({:05.02f}%)".format(
             bumblebee.util.bytefmt(used),
diff --git a/bumblebee/modules/pulseaudio.py b/bumblebee/modules/pulseaudio.py
index eeba28c..5e60d55 100644
--- a/bumblebee/modules/pulseaudio.py
+++ b/bumblebee/modules/pulseaudio.py
@@ -111,7 +111,7 @@ class Module(bumblebee.engine.Module):
                         return
         except Exception:
             self._failed = True
-            if self.parameter("autostart", "false") == "true":
+            if bumblebee.util.asbool(self.parameter("autostart", False)):
                 try:
                     bumblebee.util.execute("pulseaudio --start")
                     self.update(widgets)
diff --git a/bumblebee/modules/stock.py b/bumblebee/modules/stock.py
index 2297c3a..390c3dd 100644
--- a/bumblebee/modules/stock.py
+++ b/bumblebee/modules/stock.py
@@ -15,6 +15,8 @@ Parameters:
 import bumblebee.input
 import bumblebee.output
 import bumblebee.engine
+import bumblebee.util
+
 import requests
 from requests.exceptions import RequestException
 
@@ -24,7 +26,7 @@ class Module(bumblebee.engine.Module):
             bumblebee.output.Widget(full_text=self.value)
         )
         self._symbols = self.parameter("symbols", "")
-        self._change = self.parameter("change", True)
+        self._change = bumblebee.util.asbool(self.parameter("change", True))
         self._currencies = self.parameter('currencies', None)
         self._baseurl = 'http://download.finance.yahoo.com/d/quotes.csv'
         self._value = self.fetch()
diff --git a/bumblebee/util.py b/bumblebee/util.py
index 9efa146..30719ea 100644
--- a/bumblebee/util.py
+++ b/bumblebee/util.py
@@ -10,6 +10,15 @@ except ImportError:
     # Python3 doesn't require this anymore
     pass
 
+
+def asbool(val):
+    if val is None:
+        return False
+    if isinstance(val, bool):
+        return val
+    val = str(val).strip().lower()
+    return val in ("t", "true", "y", "yes", "on", "1")
+
 def execute(cmd, wait=True):
     logging.info("executing command '{}'".format(cmd))
     args = shlex.split(cmd)