diff --git a/qml/Led.qml b/qml/Led.qml
new file mode 100644
index 0000000..6fe8fbb
--- /dev/null
+++ b/qml/Led.qml
@@ -0,0 +1,20 @@
+import QtQuick 2.0
+import QtGraphicalEffects 1.0
+
+/**
+ * Led: a circle color
+ */
+
+RadialGradient {
+	property color led_color: "red"
+	gradient: Gradient {
+		GradientStop {
+			position: 0.0
+			color: led_color
+		}
+		GradientStop {
+			position: 0.5
+			color: "transparent"
+		}
+	}
+}
diff --git a/qml/Scene.qml b/qml/Scene.qml
index 45bc965..cc91aa4 100644
--- a/qml/Scene.qml
+++ b/qml/Scene.qml
@@ -18,7 +18,8 @@ Item {
 		property int note: 2
 		property int octave: 4
 		property double freq: 440
-		property double deviation: 0.1
+		property double deviation: 0.12
+		property bool found: true
 	}
 
 	TunerScreen {
diff --git a/qml/TunerScreen.qml b/qml/TunerScreen.qml
index 5cd6370..72113f4 100644
--- a/qml/TunerScreen.qml
+++ b/qml/TunerScreen.qml
@@ -18,6 +18,35 @@ Item {
 	// landscape / portrait
 	property bool is_portrait: height > width
 
+	// maximum absolute deviation to display green led
+	property double deviation_ok: 0.1
+	property color led_green: "green"
+	property color led_red: "red"
+
+	property bool dev_is_ok: Math.abs(tuner.deviation) <= deviation_ok
+
+	Led {
+		anchors.top: meter.top
+		anchors.left: meter.left
+		anchors.topMargin: meter.width / 24 
+		anchors.leftMargin: anchors.topMargin
+		width: meter.width / 12
+		height: width
+		led_color: dev_is_ok ? led_green : led_red
+		visible: tuner.found && (dev_is_ok || tuner.deviation < 0)
+	}
+
+	Led {
+		anchors.top: meter.top
+		anchors.right: meter.right
+		anchors.topMargin: meter.width / 24 
+		anchors.rightMargin: anchors.topMargin
+		width: meter.width / 12
+		height: width
+		led_color: dev_is_ok ? led_green : led_red
+		visible: tuner.found && (dev_is_ok || tuner.deviation > 0)
+	}
+
 	CircleMeter {
 		id: meter
 		theme: parent.theme
diff --git a/qml/desktop.qrc b/qml/desktop.qrc
index 47729ec..6a386f6 100644
--- a/qml/desktop.qrc
+++ b/qml/desktop.qrc
@@ -7,5 +7,6 @@
 <file>CircleMeter.qml</file>
 <file>ScaleToise.qml</file>
 <file>Toise.qml</file>
+<file>Led.qml</file>
 </qresource>
 </RCC>
diff --git a/qml/sailfish.qrc b/qml/sailfish.qrc
index 522404c..d05a64a 100644
--- a/qml/sailfish.qrc
+++ b/qml/sailfish.qrc
@@ -6,5 +6,6 @@
 <file>CircleMeter.qml</file>
 <file>ScaleToise.qml</file>
 <file>Toise.qml</file>
+<file>Led.qml</file>
 </qresource>
 </RCC>