fan_control

#!/usr/bin/python3

import sys
import os
import time
import RPi.GPIO as GPIO
import pigpio
import datetime
from max31865 import max31865
from influxdb import InfluxDBClient

# Temp config vars
check_interval = 15  # in seconds
max_temp = 34  # fans at max rpm
min_temp = 26  # fans at min rpm

# PWM settings
pwm_pin = 12
pwm_interval = 50
pwm_frequency = 20000
pwm_max_dc = 255
pwm_min_dc = 50

# InfluxDB setup
client = InfluxDBClient(host = '192.168.1.200', port = 8086, username = 'user', password = 'password')
client.switch_database(database = 'telegraf')

# Setup objects
rtd = max31865()
pi = pigpio.pi()
pi.set_mode(pwm_pin, pigpio.OUTPUT)
pi.set_PWM_frequency(pwm_pin, pwm_frequency)

# Main loop
while True:
    temp_c = rtd.readTemp()
    if temp_c >= max_temp:
        pwm = pwm_max_dc
    elif temp_c <= min_temp:
        pwm = pwm_min_dc
    else:
        temp_pct_max = (temp_c - min_temp) / (max_temp - min_temp)
        temp_pwm = (temp_pct_max * (pwm_max_dc - pwm_min_dc)) + pwm_min_dc
        pwm = int(temp_pwm) - int(temp_pwm) % pwm_interval

    pi.set_PWM_dutycycle(pwm_pin, pwm)

    json_body = [
        {
        "measurement": "server_chassis",
        "tags": {"host": "tempo"},
        "time": datetime.datetime.utcnow().strftime('%Y-%m-%dT%H:%M:%SZ'),
        "fields": {
            "temp_c": temp_c,
            "pwm": pwm
            }
        }
    ]
    print(json_body)

    client.write_points(json_body)
    time.sleep(check_interval)