adc_temperature: Support defining custom sensors in the config file

Allow the user to define a custom sensor with their own set of
temperature/voltage measurements.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/example-extras.cfg

@@ -395,7 +395,7 @@
 
 
 # Custom thermistors (one may define any number of sections with a
-# "thermistor" prefix).  A custom thermistor may be used in the
+# "thermistor" prefix). A custom thermistor may be used in the
 # sensor_type field of a heater config section. (For example, if one
 # defines a "[thermistor my_thermistor]" section then one may use a
 # "sensor_type: my_thermistor" when defining a heater.) Be sure to
@@ -410,7 +410,7 @@
 #resistance3:
 #   Three resistance measurements (in Ohms) at the given temperatures
 #   (in Celsius). The three measurements will be used to calculate the
-#   Steinhart-Hart coefficients for the thermistor.  These parameters
+#   Steinhart-Hart coefficients for the thermistor. These parameters
 #   must be provided when using Steinhart-Hart to define the
 #   thermistor.
 #beta:
@@ -419,6 +419,28 @@
 #   provided when using "beta" to define the thermistor.
 
 
+# Custom ADC temperature sensors (one may define any number of
+# sections with an "adc_temperature" prefix). This allows one to
+# define a custom temperature sensor that measures a voltage on an
+# Analog to Digital Converter (ADC) pin and uses linear interpolation
+# between a set of configured temperature/voltage measurements to
+# determine the temperature. The resulting sensor can be used as a
+# sensor_type in a heater section. (For example, if one defines a
+# "[adc_temperature my_sensor]" section then one may use a
+# "sensor_type: my_sensor" when defining a heater.) Be sure to place
+# the sensor section in the config file above its first use in a
+# heater section.
+#[adc_temperature my_sensor]
+#temperature1:
+#voltage1:
+#temperature2:
+#voltage2:
+#...
+#   A set of temperatures (in Celsius) and voltages (in Ohms) to use
+#   as reference when converting a temperature. At least two
+#   measurements must be provided.
+
+
 # Replicape support - see the generic-replicape.cfg file for further
 # details.
 #[replicape]

klippy/extras/adc_temperature.py

@@ -72,6 +72,20 @@ class Linear:
         gain, offset = self.slope_samples[pos]
         return (temp - offset) / gain
 
+# Custom defined sensors from the config file
+class CustomLinear:
+    def __init__(self, config):
+        self.name = " ".join(config.get_name().split()[1:])
+        self.params = []
+        for i in range(1, 1000):
+            t = config.getfloat("temperature%d" % (i,), None)
+            if t is None:
+                break
+            v = config.getfloat("voltage%d" % (i,))
+            self.params.append((t, v))
+    def create(self, config):
+        return Linear(config, self.params)
+
 AD595 = [
     (0., .0027), (10., .101), (20., .200), (25., .250), (30., .300), (40., .401),
     (50., .503), (60., .605), (80., .810), (100., 1.015), (120., 1.219),
@@ -99,3 +113,8 @@ def load_config(config):
     for sensor_type, params in [("AD595", AD595), ("PT100 INA826", PT100)]:
         func = (lambda config, params=params: Linear(config, params))
         pheater.add_sensor(sensor_type, func)
+
+def load_config_prefix(config):
+    linear = CustomLinear(config)
+    pheater = config.get_printer().lookup_object("heater")
+    pheater.add_sensor(linear.name, linear.create)