diff --git a/projekte/charlieplexing/eagle/4pins.sch b/projekte/charlieplexing/eagle/4pins.sch
new file mode 100644
index 0000000..029a829
Binary files /dev/null and b/projekte/charlieplexing/eagle/4pins.sch differ
diff --git a/projekte/charlieplexing/eagle/eagle.epf b/projekte/charlieplexing/eagle/eagle.epf
new file mode 100644
index 0000000..b2b33d6
--- /dev/null
+++ b/projekte/charlieplexing/eagle/eagle.epf
@@ -0,0 +1,2 @@
+[Eagle]
+Version="05 07 00"
\ No newline at end of file
diff --git a/projekte/charlieplexing/sketch_may18a/sketch_may18a.pde b/projekte/charlieplexing/sketch_may18a/sketch_may18a.pde
new file mode 100644
index 0000000..e56cf89
--- /dev/null
+++ b/projekte/charlieplexing/sketch_may18a/sketch_may18a.pde
@@ -0,0 +1,32 @@
+const int pins[] = {2, 3, 4};
+
+void setup() {
+  for(int p=0; p<=2; p++) {
+    pinMode(pins[p], INPUT); 
+  }
+}
+
+const int charlieplexed[6][3] =
+{
+  { 1,0,-1},
+  { 0,1,-1},
+  {-1,1, 0},
+  {-1,0, 1},
+  {1,-1, 0},
+  {0,-1, 1},
+};
+
+void loop() {
+  for(int i=0; i<=5; i++) {
+    // set pin tristate
+    for(int p=0; p<=2; p++) {
+      if (charlieplexed[i][p] == -1) {
+        pinMode(pins[p], INPUT);
+      } else {
+        pinMode(pins[p], OUTPUT);
+        digitalWrite(pins[p], charlieplexed[i][p]);
+      }
+    }
+  delay(200);
+  }
+}
diff --git a/projekte/charlieplexing/sketch_may18b/sketch_may18b.pde b/projekte/charlieplexing/sketch_may18b/sketch_may18b.pde
new file mode 100644
index 0000000..ccbec3d
--- /dev/null
+++ b/projekte/charlieplexing/sketch_may18b/sketch_may18b.pde
@@ -0,0 +1,38 @@
+const int pins[] = {2, 3, 4, 5};
+
+void setup() {
+  for(int p=0; p<=2; p++) {
+    pinMode(pins[p], INPUT); 
+  }
+}
+
+const int charlieplexed[12][4] =
+{
+  { 1,0,-1, -1},
+  { 0,1,-1, -1},
+  {-1,1, 0, -1},
+  {-1,0, 1, -1},
+  {-1,-1,1,  0},
+  {-1,-1,0,  1},
+  {1,-1, 0, -1},
+  {0,-1, 1, -1},
+  {-1,1,-1,  0},
+  {-1,0,-1,  1},
+  {1,-1,-1,  0},
+  {0,-1,-1,  1},
+};
+
+void loop() {
+  for(int i=0; i<=11; i++) {
+    // set pin tristate
+    for(int p=0; p<=3; p++) {
+      if (charlieplexed[i][p] == -1) {
+        pinMode(pins[p], INPUT);
+      } else {
+        pinMode(pins[p], OUTPUT);
+        digitalWrite(pins[p], charlieplexed[i][p]);
+      }
+    }
+  delay(200);
+  }
+}