diff --git a/generate-defines.py b/generate-defines.py
new file mode 100755
index 0000000..5acc08c
--- /dev/null
+++ b/generate-defines.py
@@ -0,0 +1,143 @@
+#!/usr/bin/env python
+import json
+import markdown
+import unicodedata
+import re
+import os
+import time
+import sys
+
+pins = None
+
+key_template = {
+    'python': '{board_name}_{name}',
+    'ruby':   '{board_name}_{name}',
+    'spin':   '    {board_name}_{name}',
+    'c':      '#define {board_name}_{name}'
+}
+
+value_template = {
+    'python': ' = {value}',
+    'ruby':   ' = {value}',
+    'spin':   ' = {value}',
+    'c':      ' {value}'
+}
+
+comment_prefix = {
+    'python': '#',
+    'ruby':   '',
+    'spin':   '\'',
+    'c':      '//'
+}
+
+def slugify(value):
+    """
+    Normalizes string, converts to lowercase, removes non-alpha characters,
+    and converts spaces to hyphens.
+    """
+    value = unicode(value)
+    value = unicodedata.normalize('NFKD', value).encode('ascii', 'ignore').decode('ascii')
+    value = value.replace('+','PLUS')
+    value = value.replace('-','MINUS')
+    value = re.sub('[^\w\s-]', '', value).strip().lower()
+    return re.sub('[-\s]+', '_', value)
+
+def bcm_to_physical(pin):
+    pin = pin[3:]
+    for idx in pins:
+        compare_pin = pins[idx]
+        if 'scheme' in compare_pin:
+            if 'bcm' in compare_pin['scheme']:
+                if compare_pin['scheme']['bcm'] == int(pin):
+                    print("Mapping BCM{} to {}".format(pin, str(idx)))
+                    return str(idx)
+
+def physical_to_bcm(pin):
+    pin = pins[pin]
+    if 'scheme' in pin:
+        if 'bcm' in pin['scheme']:
+            return str(pin['scheme']['bcm'])
+    return None
+
+def physical_to_wiringpi(pin):
+    pin = pins[pin]
+    if 'scheme' in pin:
+        if 'wiringpi' in pin['scheme']:
+            return str(pin['scheme']['wiringpi'])
+    return None
+
+def physical_to(pin, scheme='bcm'):
+    if scheme in ['bcm','wiringpi']:
+        pin = pins[pin]
+        if 'scheme' in pin:
+            if scheme in pin['scheme']:
+                return str(pin['scheme'][scheme])
+    elif scheme == 'physical':
+        return pin
+    return None
+
+db = json.load(open('pi-pinout.json'))
+pins = db['pins']
+
+define = {}
+keys = []
+
+def add_define(key, value):
+    global keys, define
+    keys.append(key)
+    define[key] = value
+
+if len(sys.argv) >= 3:
+
+    overlay_file = sys.argv[1]
+    pin_scheme   = sys.argv[2]
+    output_lang  = sys.argv[3]
+
+    overlay = json.load(open('overlay/{}.json'.format(overlay_file)))
+
+    if 'i2c' in overlay:
+        for addr in overlay['i2c']:
+            info = overlay['i2c'][addr]
+
+            add_define('ADDR_' + slugify(info['name']).upper(), addr)
+
+    if 'pin' in overlay:
+        for pin in overlay['pin']:
+            info = overlay['pin'][pin]
+            if str(pin).startswith('bcm'):
+                pin = bcm_to_physical(pin)
+
+
+            if 'name' in info:
+                name = slugify(info['name']).upper()
+            else:
+                name = slugify(pins[pin]['name']).upper()
+
+            add_define(name, physical_to(pin, pin_scheme))
+
+    board_name = slugify(overlay['name']).upper()
+
+    print(comment_prefix[output_lang] + ' Pin definitions for ' + overlay['name'])
+    print(comment_prefix[output_lang] + ' Using the {} pin numbering scheme'.format(pin_scheme))
+
+    row_length = 0
+
+    for name in define:
+        key = key_template[output_lang].format(
+            board_name = board_name,
+            name = name
+        )
+        row_length = max(len(key),row_length)
+
+
+    for name in keys:
+        key = key_template[output_lang].format(
+            board_name = board_name,
+            name = name
+        )
+        
+        value = value_template[output_lang].format(value = define[name])
+
+        value = value.rjust(row_length - len(key) + len(value),' ')
+
+        print(key+value)
diff --git a/overlay/explorer-hat-pro.json b/overlay/explorer-hat-pro.json
index 658b2e3..47b740c 100644
--- a/overlay/explorer-hat-pro.json
+++ b/overlay/explorer-hat-pro.json
@@ -6,7 +6,26 @@
 	"buy": "http://shop.pimoroni.com/products/explorer-hat",
 	"description": "An all-in-one light, input, motor, touch and output add-on board.",
 	"pincount": 40,
+	"i2c": {
+		"0x28": {
+			"name":   "Cap Touch",
+			"device": "cap1208"
+		},
+		"0x48": {
+			"name":   "Analog Input",
+			"device": "ads1015"
+		}
+	},
 	"pin": {
+		"3": {},
+		"5": {},
+		"8": {},
+		"10": {},
+		"12": {},
+		"19": {},
+		"21": {},
+		"23": {},
+		"24": {},
 		"7": {
 			"name": "LED 1",
 			"mode": "output",