ESP8266 MQTT Roomba controller (Useful for hooking up old Roombas to Home Assistant)

• ESP12E ESP8266 Wifi microcontroller ($3-4) Though any ESP module will probably work
• Small 3.3V switching step-down regulator ($1-2)
• 5kOhm & 10kOhm resistor for 5V->3.3V voltage divider (any two resistors above a few kOhm with a 1:2 ratio should work)
• Some ~10kOhm pullup/pulldown resistors to get the ESP12E in the right modes for programming (probably anything 2k-20kOhm will work fine)
• 3.3V FTDI cable for initial programming
• Some wire you can jam into the Roomba's Mini Din connector, or a proper Mini Din connector

• ESP GPIO15 -> 10kOhm Resistor -> GND
• ESP GPIO0 -> 10kOhm Resistor -> 3.3V
• ESP EN -> 10kOhm Resistor -> 3.3V
• ESP TX -> Roomba RX (Pin3 on Roomba's Mini Din connector)
• Roomba TX (Pin4 on Roomba) -> 5kOhm -> ESP RX -> 10kOhm -> GND
• ESP GPIO14 -> Roomba BRC (Pin5 on Roomba)
• ESP 3.3V -> Voltage regulator 3.3V
• ESP GND -> Voltage regulator GND
• Voltage regulator Vin -> Roomba Vpwr (Pin 1 or 2 on Roomba)
• Voltage regulator GND -> Roomba GND (Pin 6 or 7 on Roomba)

Note that I used a voltage divider from the Roomba TX pin to the ESP12E RX pin since the Roomba serial is 5V and the ESP is 3.3V. I used a 5kOhm resistor and a 10kOhm resistor but anything above a few kOhm with a 1:2 ratio should be fine.

First off you'll need to create a src/secrets.h. This file is .gitignore'd so you don't put your passwords on Github.

cp src/secrets.example.h src/secrets.h

Then edit your src/secrets.h file to reflect your wifi ssid/password and MQTT server password (if you're using the Home Assistant built-in broker, this is just your API password).

You may also need to modify the values in src/config.h (particularly MQTT_SERVER) to match your setup.

The easiest way to build and upload the code is with the PlatformIO IDE.

The first time you program your board you'll want to do it over USB/Serial. After that, programming can be done over wifi (via ArduinoOTA). To program over USB/Serial, change the upload_port in the platformio.ini file to point to the appropriate device for your board. Probably something like the following will work if you're on a Mac.

upload_port = /dev/tty.cu*

If you're not using an ESP12E board, you'll also want to update the board line with your board. See here for other PlatformIO supported ESP8266 board. For example, for the Wemos D1 Mini:

board = d1_mini

After that, from the PlatformIO Atom IDE, you should be able to go to PlatformIO->Upload in the menu.

Mosquitto can be super useful for testing this code. For example the following commands can be used publish and subscribe to messages to and from the vacuum respectively.

export MQTT_SERVER=YOURSERVERHOSTHERE
export MQTT_USER=homeassistant
export MQTT_PASSWORD=PROBABLYYOURHOMEASSISTANTPASSWORD
mosquitto_pub -t 'vacuum/command' -h $MQTT_SERVER -p 1883 -u $MQTT_USER -P $MQTT_PASSWORD -V mqttv311 -m "turn_on"
mosquitto_sub -t 'vacuum/#' -v -h $MQTT_SERVER -p 1883 -u $MQTT_USER -P $MQTT_PASSWORD -V mqttv311

Included in the firmware is a telnet debugging interface. To connect run telnet roomba.local. With that you can log messages from code with the DLOG macro and also send commands back that the code can act on (see the debugCallback function).

Newer Roomba 650s (2016 and newer) fall asleep after ~1 minute of being on the dock. Though the iRobot Create 2 docs say that you can keep a Roomba awake by pulsing the BRC pin low, it doesn't seem to work for newer Roomba 650s when they are on the dock. Thinking Cleaner's docs note that this is likely a bug, and they have a workaround to keep the Roomba awake while docked. I haven't figured out the magic sequence to keep Roomba 650s awake on the dock (see this code comment for what I've tried).