diff --git a/esphomeyaml/config_validation.py b/esphomeyaml/config_validation.py
index a3e00fd89d..6ae3932271 100644
--- a/esphomeyaml/config_validation.py
+++ b/esphomeyaml/config_validation.py
@@ -56,8 +56,10 @@ def alphanumeric(value):
 
 def valid_name(value):
     value = string_strict(value)
-    if not all(c in ALLOWED_NAME_CHARS for c in value):
-        raise vol.Invalid(u"Valid characters for name are {}".format(ALLOWED_NAME_CHARS))
+    for c in value:
+        if c not in ALLOWED_NAME_CHARS:
+            raise vol.Invalid(u"'{}' is an invalid character for names. Valid characters are: {}"
+                              u"".format(c, ALLOWED_NAME_CHARS))
     return value
 
 
diff --git a/examples/sonoff_s20.yaml b/examples/sonoff_s20.yaml
new file mode 100644
index 0000000000..72eafef9e5
--- /dev/null
+++ b/examples/sonoff_s20.yaml
@@ -0,0 +1,50 @@
+esphomeyaml:
+  name: <NAME_OF_NODE>
+  platform: ESP8266
+  board: esp01_1m
+  board_flash_mode: dout
+
+wifi:
+  ssid: <YOUR_SSID>
+  password: <YOUR_PASSWORD>
+
+mqtt:
+  broker: <YOUR_MQTT_BROKER>
+  username: <YOUR_USERNAME>
+  password: <YOUR_PASSWORD>
+
+logger:
+
+ota:
+
+binary_sensor:
+  - platform: gpio
+    pin:
+      number: GPIO0
+      mode: INPUT_PULLUP
+      inverted: True
+    name: "Sonoff S20 Button"
+    on_press:
+      then:
+        - switch.toggle:
+            id: relay
+  - platform: status
+    name: "Sonoff S20 Status"
+
+
+switch:
+  - platform: gpio
+    name: "Sonoff S20 Relay"
+    pin: GPIO12
+    id: relay
+
+output:
+  - platform: esp8266_pwm
+    id: s20_green_led
+    pin: GPIO13
+    inverted: True
+
+light:
+  - platform: monochromatic
+    name: "Sonoff S20 Green LED"
+    output: s20_green_led