diff --git a/src/device/output/key/char.go b/src/device/output/key/char.go
index 99caff5..3c4dfb1 100644
--- a/src/device/output/key/char.go
+++ b/src/device/output/key/char.go
@@ -1,7 +1,35 @@
 package key
 
+import "os"
+
 var (
 	charToKey = map[byte]Key{
+		'A': AUpper,
+		'B': BUpper,
+		'C': CUpper,
+		'D': DUpper,
+		'E': EUpper,
+		'F': FUpper,
+		'G': GUpper,
+		'H': HUpper,
+		'I': IUpper,
+		'J': JUpper,
+		'K': KUpper,
+		'L': LUpper,
+		'M': MUpper,
+		'N': NUpper,
+		'O': OUpper,
+		'P': PUpper,
+		'Q': QUpper,
+		'R': RUpper,
+		'S': SUpper,
+		'T': TUpper,
+		'U': UUpper,
+		'V': VUpper,
+		'W': WUpper,
+		'X': XUpper,
+		'Y': YUpper,
+		'Z': ZUpper,
 		'a': A,
 		'b': B,
 		'c': C,
@@ -56,8 +84,10 @@ func ToChar(k Key) byte {
 	return v
 }
 
+var caseSensitive = os.Getenv("CASE_SENSITIVE") != "true"
+
 func FromChar(b byte) Key {
-	if 'A' <= b && b <= 'Z' {
+	if !caseSensitive && 'A' <= b && b <= 'Z' {
 		b += 'a' - 'A'
 	}
 	v, ok := charToKey[b]
diff --git a/src/device/output/key/char_test.go b/src/device/output/key/char_test.go
index 70ef594..112ca66 100644
--- a/src/device/output/key/char_test.go
+++ b/src/device/output/key/char_test.go
@@ -3,6 +3,7 @@ package key
 import "testing"
 
 func TestFromChar(t *testing.T) {
+	caseSensitive = false
 	if got := FromChar('1'); got != N1 {
 		t.Error(got)
 	}
@@ -21,4 +22,11 @@ func TestFromChar(t *testing.T) {
 	if got := ToChar(-1); got != '?' {
 		t.Error(got)
 	}
+	caseSensitive = true
+	if got := FromChar('a'); got != A {
+		t.Error(got)
+	}
+	if got := FromChar('A'); got != AUpper {
+		t.Error(got)
+	}
 }
diff --git a/src/device/output/key/keys.go b/src/device/output/key/keys.go
index 617c270..218fbcb 100644
--- a/src/device/output/key/keys.go
+++ b/src/device/output/key/keys.go
@@ -1,45 +1,69 @@
 package key
 
-import "github.com/micmonay/keybd_event"
-
 type Key int
 
 const (
-	Undef = Key(keybd_event.VK_SP11)
-	A     = Key(keybd_event.VK_A)
-	B     = Key(keybd_event.VK_B)
-	C     = Key(keybd_event.VK_C)
-	D     = Key(keybd_event.VK_D)
-	E     = Key(keybd_event.VK_E)
-	F     = Key(keybd_event.VK_F)
-	G     = Key(keybd_event.VK_G)
-	H     = Key(keybd_event.VK_H)
-	I     = Key(keybd_event.VK_I)
-	J     = Key(keybd_event.VK_J)
-	K     = Key(keybd_event.VK_K)
-	L     = Key(keybd_event.VK_L)
-	M     = Key(keybd_event.VK_M)
-	N     = Key(keybd_event.VK_N)
-	O     = Key(keybd_event.VK_O)
-	P     = Key(keybd_event.VK_P)
-	Q     = Key(keybd_event.VK_Q)
-	R     = Key(keybd_event.VK_R)
-	S     = Key(keybd_event.VK_S)
-	T     = Key(keybd_event.VK_T)
-	U     = Key(keybd_event.VK_U)
-	V     = Key(keybd_event.VK_V)
-	W     = Key(keybd_event.VK_W)
-	X     = Key(keybd_event.VK_X)
-	Y     = Key(keybd_event.VK_Y)
-	Z     = Key(keybd_event.VK_Z)
-	N1    = Key(keybd_event.VK_1)
-	N2    = Key(keybd_event.VK_2)
-	N3    = Key(keybd_event.VK_3)
-	N4    = Key(keybd_event.VK_4)
-	N5    = Key(keybd_event.VK_5)
-	N6    = Key(keybd_event.VK_6)
-	N7    = Key(keybd_event.VK_7)
-	N8    = Key(keybd_event.VK_8)
-	N9    = Key(keybd_event.VK_9)
-	N0    = Key(keybd_event.VK_0)
+	Undef = iota
+	A
+	B
+	C
+	D
+	E
+	F
+	G
+	H
+	I
+	J
+	K
+	L
+	M
+	N
+	O
+	P
+	Q
+	R
+	S
+	T
+	U
+	V
+	W
+	X
+	Y
+	Z
+	AUpper
+	BUpper
+	CUpper
+	DUpper
+	EUpper
+	FUpper
+	GUpper
+	HUpper
+	IUpper
+	JUpper
+	KUpper
+	LUpper
+	MUpper
+	NUpper
+	OUpper
+	PUpper
+	QUpper
+	RUpper
+	SUpper
+	TUpper
+	UUpper
+	VUpper
+	WUpper
+	XUpper
+	YUpper
+	ZUpper
+	N1
+	N2
+	N3
+	N4
+	N5
+	N6
+	N7
+	N8
+	N9
+	N0
 )