Espresso PID Controller Save

Espresso PID Controller

PID controller being used on a pre-2015 Gaggia Classic boiler

The slow responding and somewhat innacturate bimetal coffee thermostat is replaced with a K type thermocouple connected to an Arduino controller that controls a Solid State Relay (SSR) to control power to the small boiler inside the espresso machine.

2022-04-20 Update

• Fix: MQTT reconnect changed from 2 to 15 to stop reconnect from blocking the rest of the loop

See CHANGELOG for previous updates

Parts used

Wemos D1 Mini

AD8495 Thermocouple amp from Adafruit

K Type thermocouple from a QIDI 3D printer with M4 threads from eBay

ADS1115 15bit ADC to provide better temperature resolution

Crydom Solid State Relay

I2C 128x64 OLED display from eBay/Amazon ( not using the OLED for daily use )

Documentation

IotWebConf Info

• AP password = espresso

MQTT

MQTT stat topic = espresso/<thingName>/stat

Example stat payload {"Name":"thingName","Uptime":60,"Runtime":60,"Setpoint":105,"Input":105.0,"Output":5.08,"ADC":28457,"Vout":1.78,"operMode":true,"Loops":27734,"steamMode":false}

MQTT command topic = espresso/<thingName>/cmnd

• {"operMode":true|false}
• {"steamMode":true|false}
• {"Setpoint":<number between 1 and 110>}