Add initial files for the HH Hacking 101 - code and infos about board will follow soon

code-snippets/KeyPad_4x4_esp32.py

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+# KeyPad Vers #2
+# Tony Goodhew 9th May 2020
+# https://www.instructables.com/Using-a-4x4-KeyPad-With-CircuitPython/
+#
+# Changes by Christopher Scheuring 2022-05-13 for ESP32 support
+#
+# Connections left to right on KeyPad
+# 0   1   2   3   4   5   6   7
+# 13  12  14  27  15  02  04  16
+
+from machine import Pin
+import gc
+import time
+
+gc.collect() # make some room
+
+# Set up LED on pin 17
+led_pin = 17
+
+led = Pin(led_pin, Pin.OUT)
+led.on() # switch off led - inverted logic!
+
+# Set up Rows
+rows = []
+for p in [13, 12, 14, 27]:
+    row = Pin(p, Pin.OUT)
+    rows.append(row)
+# anodes OFF
+for i in range(4):
+    rows[i].off()
+
+# Set up columns
+cols = []
+for p in [15, 02, 04, 16]:
+    col = Pin(p, Pin.IN, Pin.PULL_DOWN)
+    cols.append(col)
+
+def getkey():  # Returns -999 or key value
+    values = [1,2,3,10, 4,5,6,11, 7,8,9,12, 14,0,15,13]
+    val = -999 # Error value for no key press
+    for count in range(10): # Try to get key press 10 times
+        for r in range(4):  # Rows, one at a time
+            rows[r].on() # row HIGH
+            for c in range(4): # Test columns, one at a time
+                if cols[c].value() == 1: # Is column HIGH?
+                    p = r * 4 + c      # Pointer to values list
+                    val = values[p]
+                    count = 11 # This stops looping
+                    led.off() # Flash LED ON if key pressed
+            rows[r].off() # row LOW
+    time.sleep(0.2) # Debounce
+    led.on() # LED OFF
+    return val
+
+def getvalue(digits): # Number of digits
+    result = 0
+    count = 0
+    while True:
+        x = getkey()
+        if x != -999 and x < 10: # Check if numeric key pressed
+            result = result * 10 + x
+            print(result)
+            count = count + 1
+        if count == digits:
+            return result
+
+# +++++ Main +++++
+print("Press 4 numeric (BLUE) keys")
+y = getvalue(4)
+print('\n',y)
+
+print("\nPress any of the keys\n # halts the program")
+
+characters =["1","2","3","4","5","6","7","8","9","A","B","C","D","*","#","0"]
+running = True
+while running:
+    x = getkey()
+    if x != -999: # A key has been pressed!
+        print(characters[x-1])
+        if x == 15:
+            running = False
+            
+led.on()