Adding temp monitor code

kiln/Adafruit_alphanumeric.py

@@ -147,7 +147,6 @@ class Alphanumeric(object):
                 
     special = dict(degree= 0b0000000011100011, cone=0b0010100000001000)
     
-  # Constructor
     def __init__(self, address=0x70, debug=False):
         self.disp = LEDBackpack(address=address, debug=debug)
 
@@ -169,12 +168,14 @@ class Alphanumeric(object):
         # Set the appropriate digit
         self.disp.setBufferRow(charNumber, value | (dot << 14))
 
+
 class AlphaScoller(threading.Thread):
     def __init__(self, address=0x70, interval=.25):
         self.interval = interval
         self.disp = Alphanumeric(address)
         super(AlphaScroller, self).__init__()
         self.value = "    "
+        self.counter = 0
     
     def set_text(self, text, pad=True):
         self.text = text
@@ -186,11 +187,9 @@ class AlphaScoller(threading.Thread):
         self.interval = interval
     
     def run(self):
-        counter = 0
         while True:
             for i in range(4):
-                char = self.value[(counter+i) % len(self.value)]
+                char = self.value[(self.counter+i) % len(self.value)]
                 self.disp.writeChar(i, char)
             time.sleep(interval)
-            counter += 1
-
+            self.counter += 1

kiln/thermo.py

@@ -0,0 +1,55 @@
+import time
+import threading
+import datetime
+from collections import deque
+
+def temp_to_cone(temp):
+    """Convert the current temperature to cone value using linear interpolation"""
+    cones = [600,614,635,683,717,747,792,804,838,852,884,894,900,923,955,984,999,1046,1060,1101,1120,1137,1154,1162,1168,1186,1196,1222,1240,1263,1280,1305,1315,1326,1346]
+    names = [str(i).replace('-', '0') for i in range(-22,0)] + [str(i) for i in range(1, 14)]
+    for i in range(len(cones)-1):
+        low, high = cones[i], cones[i+1]
+        if low <= temp < high:
+            frac = (temp - low) / float(high - low)
+            return names[i]+'.%d'%int(frac*10)
+    return "13+"
+
+class Monitor(threading.Thread):
+    def __init__(self, name="3b-000000182b57"):
+        self.device = "/sys/bus/w1/devices/%s/w1_slave"%name
+        self.history = deque(maxlen=1024)
+
+        from Adafruit_alphanumeric import AlphaScroller
+        self.display = AlphaScroller(interval=.4)
+        self.display.start()
+
+    def _read_temp(self):
+        with open(self.device, 'r') as f:
+            lines = f.readlines()
+
+        while lines[0].strip()[-3:] != 'YES':
+            time.sleep(0.2)
+            with open(self.device, 'r') as f:
+                lines = f.readlines()
+
+        match = re.match(r'^[0-9a-f\s]{27}t=(\d+)$', lines[1])
+        if match is not None:
+            return float(match.group(1)) / 1000.0
+
+    @property
+    def temperature(self):
+        return self.history[-1][1]
+
+    def run(self):
+        while True:
+            temp = self._read_temp()
+            fahr = temp * 9. / 5. + 32.
+            now = datetime.datetime()
+            self.history.append((now, temp))
+            
+            text = list('%0.0f'%temp) + ['degree'] + list('C  %0.0f'%fahr)+['degree'] + list("F")
+
+            if 600 <= temp:
+                text += [' ', ' ', 'cone']+list("%0.1f"%temp_to_cone(temp))
+            text += '    '
+            self.display.text = text