diff --git a/read_arduino.py b/read_arduino.py
index 1921f63..32a6510 100644
--- a/read_arduino.py
+++ b/read_arduino.py
@@ -46,6 +46,9 @@ def read():
         while True:
             dat_list = np.random.randint(0, v_in * 1000, SENSORS_MAX)  # create a randomized voltage data
             # take only the nonzero indices, and truncated to two decimal places to "filter" out some hardware errors
+            # According to the actual req, the data in the data list should be (3.3-data)
+            for x in range(dat_list.size):
+                np.put(dat_list, x, 3.3 - dat_list[x])
             dat_sel = np.trunc((np.take(dat_list, sensor_ports) / 1000) * 10**2) / 10**2
             r_arr = np.take(refRes, sensor_ports) * (v_in / dat_sel - 1) # *2 <-- change with actual formula for ammonia concentration
             # created a new array to convert resistance values to sci notation
@@ -84,6 +87,9 @@ def read():
             read_data = controller.readline().decode("utf-8")
             # use numpy so it can make list calculations easier (and possibly faster)
             dat_list = np.asarray(json.loads(read_data), dtype=np.float32)[:SENSORS_MAX]
+            # According to the actual req, the data in the data list should be (3.3-data)
+            for x in range(dat_list.size):
+                np.put(dat_list, x, 3.3 - dat_list[x])
             dat_sel = np.take(dat_list, sensor_ports)
             # if we decided to switch back to analogRead(), replace this line of comment to the algorithm to something like the commented line below
             # dat_sel = np.take(dat_list, sensor_ports) * v_in / resolution