esphome/esphome/components/ntc/sensor.py
Otto Winter 056c72d50d
Drop Python 2 Support (#793)
* Remove Python 2 support

* Remove u-strings

* Remove docker symlinks

* Remove from travis

* Update requirements

* Upgrade flake8/pylint

* Fixes

* Manual

* Run pyupgrade

* Lint

* Remove base_int

* Fix

* Update platformio_api.py

* Update component.cpp
2019-12-07 18:28:55 +01:00

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from math import log
import esphome.config_validation as cv
import esphome.codegen as cg
from esphome.components import sensor
from esphome.const import CONF_CALIBRATION, CONF_ID, CONF_REFERENCE_RESISTANCE, \
CONF_REFERENCE_TEMPERATURE, CONF_SENSOR, CONF_TEMPERATURE, CONF_VALUE, ICON_THERMOMETER, \
UNIT_CELSIUS
ntc_ns = cg.esphome_ns.namespace('ntc')
NTC = ntc_ns.class_('NTC', cg.Component, sensor.Sensor)
CONF_B_CONSTANT = 'b_constant'
CONF_A = 'a'
CONF_B = 'b'
CONF_C = 'c'
ZERO_POINT = 273.15
def validate_calibration_parameter(value):
if isinstance(value, dict):
return cv.Schema({
cv.Required(CONF_TEMPERATURE): cv.float_,
cv.Required(CONF_VALUE): cv.float_,
})(value)
value = cv.string(value)
parts = value.split('->')
if len(parts) != 2:
raise cv.Invalid("Calibration parameter must be of form 3000 -> 23°C")
voltage = cv.resistance(parts[0].strip())
temperature = cv.temperature(parts[1].strip())
return validate_calibration_parameter({
CONF_TEMPERATURE: temperature,
CONF_VALUE: voltage,
})
def calc_steinhart_hart(value):
r1 = value[0][CONF_VALUE]
r2 = value[1][CONF_VALUE]
r3 = value[2][CONF_VALUE]
t1 = value[0][CONF_TEMPERATURE] + ZERO_POINT
t2 = value[1][CONF_TEMPERATURE] + ZERO_POINT
t3 = value[2][CONF_TEMPERATURE] + ZERO_POINT
l1 = log(r1)
l2 = log(r2)
l3 = log(r3)
y1 = 1/t1
y2 = 1/t2
y3 = 1/t3
g2 = (y2-y1)/(l2-l1)
g3 = (y3-y1)/(l3-l1)
c = (g3-g2)/(l3-l2) * 1/(l1+l2+l3)
b = g2 - c*(l1*l1 + l1*l2 + l2*l2)
a = y1 - (b + l1*l1*c) * l1
return a, b, c
def calc_b(value):
beta = value[CONF_B_CONSTANT]
t0 = value[CONF_REFERENCE_TEMPERATURE] + ZERO_POINT
r0 = value[CONF_REFERENCE_RESISTANCE]
a = (1/t0) - (1/beta) * log(r0)
b = 1/beta
c = 0
return a, b, c
def process_calibration(value):
if isinstance(value, dict):
value = cv.Schema({
cv.Required(CONF_B_CONSTANT): cv.float_,
cv.Required(CONF_REFERENCE_TEMPERATURE): cv.temperature,
cv.Required(CONF_REFERENCE_RESISTANCE): cv.resistance,
})(value)
a, b, c = calc_b(value)
elif isinstance(value, list):
if len(value) != 3:
raise cv.Invalid("SteinhartHart Calibration must consist of exactly three values")
value = cv.Schema([validate_calibration_parameter])(value)
a, b, c = calc_steinhart_hart(value)
else:
raise cv.Invalid("Calibration parameter accepts either a list for steinhart-hart "
"calibration, or mapping for b-constant calibration, "
"not {}".format(type(value)))
return {
CONF_A: a,
CONF_B: b,
CONF_C: c,
}
CONFIG_SCHEMA = sensor.sensor_schema(UNIT_CELSIUS, ICON_THERMOMETER, 1).extend({
cv.GenerateID(): cv.declare_id(NTC),
cv.Required(CONF_SENSOR): cv.use_id(sensor.Sensor),
cv.Required(CONF_CALIBRATION): process_calibration,
}).extend(cv.COMPONENT_SCHEMA)
def to_code(config):
var = cg.new_Pvariable(config[CONF_ID])
yield cg.register_component(var, config)
yield sensor.register_sensor(var, config)
sens = yield cg.get_variable(config[CONF_SENSOR])
cg.add(var.set_sensor(sens))
calib = config[CONF_CALIBRATION]
cg.add(var.set_a(calib[CONF_A]))
cg.add(var.set_b(calib[CONF_B]))
cg.add(var.set_c(calib[CONF_C]))