diff --git a/libs3/gstt.py b/libs3/gstt.py
index 6c0186e..17dc0c9 100644
--- a/libs3/gstt.py
+++ b/libs3/gstt.py
@@ -68,6 +68,7 @@ GridDisplay = [0,0,0,0]
 
 # Transformation Matrix for each laser 
 EDH = [[], [], [], []]
+# EDH = [[], [], [], []]
 
 # Etherdreams reports 
 # ipconn is initial newdac to its etherdream
diff --git a/libs3/homographyp.py b/libs3/homographyp.py
index b741cdd..77743be 100644
--- a/libs3/homographyp.py
+++ b/libs3/homographyp.py
@@ -150,12 +150,13 @@ def find_affine(points1,points2):
 	H[2,2] = 1
 	return H
 
-def apply(H,points):
-	p = np.ones((len(points),2),'float64')
-	p[:,:2] = points
-	pp = np.dot(p,H.T)
-	pp[:,:2]/=pp[:,2].reshape(len(p),1)
-	return pp[:,:2]
+
+def apply(H, points):
+	p = np.ones((len(points), 3), 'float64')
+	p[:, :3] = points
+	pp = np.dot(p, H.T)
+	pp[:, :2] /= pp[:, 2].reshape(len(p), 1)
+	return pp[:, :2]
 
 # Align and axis swap corrections 
 # Reference points 
diff --git a/libs3/tracer_common.py b/libs3/tracer_common.py
index a5c855b..f2c4459 100644
--- a/libs3/tracer_common.py
+++ b/libs3/tracer_common.py
@@ -95,13 +95,9 @@ class Status(object):
                 print(prefix + l)
 
 
-def OnePointIterator(pl):
+def OnePointIterator(ref):
     while True:
-        for indexpoint, currentpoint in enumerate(pl):
-            print("cp", indexpoint, currentpoint)
-            yield currentpoint[0], currentpoint[1], 255, 255, 255
-        continue
-        for indexpoint, currentpoint in enumerate(pl):
+        for indexpoint, currentpoint in enumerate(ref.pl):
 
             # We modify the point geometry according to warp settings
             # print indexpoint, currentpoint
@@ -327,7 +323,7 @@ class Tracer(object):
             # pdb.set_trace()
             # How much room?
             capacity = self.get_points_capacity()
-            iterator = iter(OnePointIterator(self.pl))
+            iterator = iter(OnePointIterator(self))
 
             self.redis.set('/cap/' + str(self.laser_id), capacity)
             points = [next(iterator) for i in range(capacity)]
diff --git a/libs3/tracer_helios.py b/libs3/tracer_helios.py
index 7c76f53..cb261c2 100644
--- a/libs3/tracer_helios.py
+++ b/libs3/tracer_helios.py
@@ -1,4 +1,5 @@
 import ctypes
+import math
 import random
 
 from libs3 import gstt
@@ -33,7 +34,7 @@ class TracerHelios(Tracer):
         self.redis = redis
         self.laser_id = laser_id
         self.PL = PL
-        self.pl = [[0,0,0]]
+        self.pl = [[0, 0, 0]]
         self.clientkey = self.redis.get("/clientkey").decode('ascii')
         self.xyrgb = self.xyrgb_prev = (0, 0, 0, 0, 0)
         self.intensity = 65280
@@ -50,7 +51,7 @@ class TracerHelios(Tracer):
         pass
 
     def get_points_capacity(self):
-        return 10
+        return 1000
 
     # def GetPoints(self, capacity):
     #     a = [2,3]
@@ -80,20 +81,14 @@ class TracerHelios(Tracer):
         return True
 
     def write(self, points):
-        # status_attempts = 0
-        # j = 0
-        # while (status_attempts < 512 and HeliosLib.GetStatus(j) != 1):
-        #     status_attempts += 1
-        # print("attempt {}".format(status_attempts))
-        # HeliosLib.WriteFrame(j, 3000, 0, ctypes.pointer(frames[i % 30]), 1000)  # Send the frame
         frame_type = HeliosPoint * self.get_points_capacity()
         frame = frame_type()
         helios_id = 0
-        # print("hello got {} points".format(len(points)))
         points = [point for point in points]
         for i, point in enumerate(points):
             x, y, r, g, b = point
-            print(x,y,r,g,b)
+            x = x if not math.isnan(x) else 0
+            y = x if not math.isnan(y) else 0
             frame[i] = HeliosPoint(int(x), int(y), int(r), int(g), int(b), 255)
         statusAttempts = 0
         # Make 512 attempts for DAC status to be ready. After that, just give up and try to write the frame anyway
@@ -101,15 +96,19 @@ class TracerHelios(Tracer):
             statusAttempts += 1
         f = ctypes.pointer(frame)
         # int HeliosDac::WriteFrame(unsigned int devNum, unsigned int pps, std::uint8_t flags, HeliosPoint* points, unsigned int numOfPoints)
-        r = HeliosLib.WriteFrame(0, 300, 0, f, len(frame))
+        ret_helios = HeliosLib.WriteFrame(0, 3000, 0, f, len(frame))
+        # @todo : detect errors
+        if ret_helios != 1:
+            print(f"ERR ]Helios DAC #{self.laser_id} returned error {ret_helios}")
 
     def get_warped_point(self, x, y):
 
         # transform in one matrix, with warp !!
         # Etherpoint all transform in one matrix, with warp !!
-        # position = homographyp.apply(gstt.EDH[self.laser_id], np.array([(x, y)]))
-        return x, y
-        # return position[0][0], position[0][1]
+        np_arr = np.array([(x, y, 0)])
+        laser_EDH = gstt.EDH[self.laser_id]
+        position = homographyp.apply(laser_EDH, np_arr)
+        return position[0][0], position[0][1]
 
 #
 # # Create sample frames