diff --git a/README.MD b/README.MD
index 3013117..85efc16 100644
--- a/README.MD
+++ b/README.MD
@@ -1,13 +1,24 @@
 # ULN2003 for ESP32
 uln2003 for `MicroPython` has been in github, here's the [link](https://github.com/IDWizard/uln2003). But it's work for `microbit`, so I change a little to transplant for my NodeMCU's `ESP-32s`. Here's the example:
 ```python
-import Stepper
-from machine import Pin
-s1 = Stepper.create(Pin(16,Pin.OUT),Pin(17,Pin.OUT),Pin(5,Pin.OUT),Pin(18,Pin.OUT), delay=2)
-s1.step(100)
-s1.step(100,-1) # or s1.step(-100)
-s1.angle(180)
-s1.angle(360,-1) # or s1.angle(-360)
+from stepper import Stepper
+
+in1 = 16
+in2 = 17
+in3 = 5
+in4 = 18
+delay = 2
+mode = 1 # 0 for half step, 1 for full step
+
+def main() -> None:
+    s1 = Stepper(in1, in2, in3, in4, delay, mode)
+    s1.step(100)
+    s1.step(100,-1)
+    s1.angle(180)
+    s1.angle(360,-1)
+
+if __name__ == "__main__":
+    main()
 ```
 function `angle` is angle, and the PIN map:
 `IN1` link `PIN_16`
diff --git a/boot.py b/boot.py
index b189fb0..7a97160 100644
--- a/boot.py
+++ b/boot.py
@@ -1,5 +1,3 @@
-# This file is executed on every boot (including wake-boot from deepsleep)
-# import esp
-# esp.osdebug(None)
-# import webrepl
-# webrepl.start()
+# from main import main
+
+# main()
diff --git a/main.py b/main.py
index d5673cb..987d5e7 100644
--- a/main.py
+++ b/main.py
@@ -1,13 +1,15 @@
-import Stepper
-from machine import Pin
-'''
-IN1 -->  16
-IN2 -->  17
-IN3 -->  5
-IN4 -->  18
-'''
-s1 = Stepper.create(Pin(16,Pin.OUT),Pin(17,Pin.OUT),Pin(5,Pin.OUT),Pin(18,Pin.OUT), delay=2)
-s1.step(100)
-s1.step(100,-1)
-s1.angle(180)
-s1.angle(360,-1)
\ No newline at end of file
+from stepper import Stepper
+
+in1 = 16
+in2 = 17
+in3 = 5
+in4 = 18
+delay = 2
+mode = 1 # 0 for half step, 1 for full step
+
+def main() -> None:
+    s1 = Stepper(in1, in2, in3, in4, delay, mode)
+    s1.step(100)
+    s1.step(100,-1)
+    s1.angle(180)
+    s1.angle(360,-1)
\ No newline at end of file
diff --git a/Stepper.py b/stepper.py
similarity index 70%
rename from Stepper.py
rename to stepper.py
index 9a1e0ea..0595b45 100644
--- a/Stepper.py
+++ b/stepper.py
@@ -1,4 +1,5 @@
 import time
+from machine import Pin
 
 # only test for uln2003
 class Stepper:
@@ -21,15 +22,17 @@ class Stepper:
         [0, 1, 0, 1],
         [1, 0, 0, 1]
     ]
-    def __init__(self, mode, pin1, pin2, pin3, pin4, delay):
-    	if mode=='FULL_STEP':
-        	self.mode = self.FULL_STEP
+    def __init__(self, pin1, pin2, pin3, pin4, delay, mode=1):
+        if mode == 1:
+            self.mode = self.FULL_STEP
+        elif mode == 0:
+            self.mode = self.HALF_STEP
         else:
-        	self.mode = self.HALF_STEP
-        self.pin1 = pin1
-        self.pin2 = pin2
-        self.pin3 = pin3
-        self.pin4 = pin4
+            raise ValueError("Mode must be either 0 or 1")
+        self.pin1 = Pin(pin1, Pin.OUT)
+        self.pin2 = Pin(pin2, Pin.OUT)
+        self.pin3 = Pin(pin3, Pin.OUT)
+        self.pin4 = Pin(pin4, Pin.OUT)
         self.delay = delay  # Recommend 10+ for FULL_STEP, 1 is OK for HALF_STEP
         
         # Initialize all to 0
@@ -49,13 +52,10 @@ class Stepper:
                 time.sleep_ms(self.delay)
         self.reset()
     def angle(self, r, direction=1):
-    	self.step(int(self.FULL_ROTATION * r / 360), direction)
+        self.step(int(self.FULL_ROTATION * r / 360), direction)
     def reset(self):
         # Reset to 0, no holding, these are geared, you can't move them
         self.pin1(0) 
         self.pin2(0) 
         self.pin3(0) 
         self.pin4(0)
-
-def create(pin1, pin2, pin3, pin4, delay=2, mode='HALF_STEP'):
-	return Stepper(mode, pin1, pin2, pin3, pin4, delay)