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README.MD

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+# 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)
+s1.angle(180)
+s1.angle(360,-1)
+```
+function `angle` is angle, and the PIN map:
+`IN1` link `PIN_16`
+`IN2` link `PIN_17`
+`IN3` link `PIN_5`
+`IN4` link `PIN_18`
+My uln2003 board like this, and stepper runing:<br />
+![uln2003](img/uln2003.jpg)      ![uln2003](img/stepper.gif)<br />

Stepper.py

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+import time
+
+# only test for uln2003
+class Stepper:
+    FULL_ROTATION = int(4075.7728395061727 / 8) # http://www.jangeox.be/2013/10/stepper-motor-28byj-48_25.html
+
+    HALF_STEP = [
+        [0, 0, 0, 1],
+        [0, 0, 1, 1],
+        [0, 0, 1, 0],
+        [0, 1, 1, 0],
+        [0, 1, 0, 0],
+        [1, 1, 0, 0],
+        [1, 0, 0, 0],
+        [1, 0, 0, 1],
+    ]
+
+    FULL_STEP = [
+        [1, 0, 1, 0],
+        [0, 1, 1, 0],
+        [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
+        else:
+        	self.mode = self.HALF_STEP
+        self.pin1 = pin1
+        self.pin2 = pin2
+        self.pin3 = pin3
+        self.pin4 = pin4
+        self.delay = delay  # Recommend 10+ for FULL_STEP, 1 is OK for HALF_STEP
+        
+        # Initialize all to 0
+        self.reset()
+        
+    def step(self, count, direction=1):
+        """Rotate count steps. direction = -1 means backwards"""
+        for x in range(count):
+            for bit in self.mode[::direction]:
+                self.pin1(bit[0])
+                self.pin2(bit[1])
+                self.pin3(bit[2])
+                self.pin4(bit[3])
+                time.sleep_ms(self.delay)
+        self.reset()
+    def angle(self, r, direction=1):
+    	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)

boot.py

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+# This file is executed on every boot (including wake-boot from deepsleep)
+# import esp
+# esp.osdebug(None)
+# import webrepl
+# webrepl.start()

main.py

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+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)