diff --git a/dmx_usb_module/dmx.pyx b/dmx_usb_module/dmx.pyx
new file mode 100644
--- /dev/null
+++ b/dmx_usb_module/dmx.pyx
@@ -0,0 +1,28 @@
+cdef extern from "fcntl.h":
+    int open(char *pathname, int flags)
+    int O_WRONLY
+
+cdef extern from "unistd.h":
+    int write(int fd, void *buf, int count)
+
+cdef extern from "string.h":
+    char *strncpy(char *dest, char *src, int n)
+
+cdef extern from "Python.h":
+    char* PyString_AsString(object string)
+
+cdef class Dmx:
+    cdef int fd
+    def __new__(self, port="/dev/dmx0"):
+        self.fd = open(port, O_WRONLY)
+        if self.fd < 0:
+            raise OSError("open failed")
+
+    def write(self, buf):
+        cdef char *cbuf
+        cbuf = PyString_AsString(buf)
+        if cbuf == NULL:
+            raise
+        res = write(self.fd, cbuf, 513)
+        if res < 0:
+            raise OSError("write failed")