Profalux 868MHz (not ZigBee) roller shutter integration to EspHome/HA

This project has been made with the help of Tam and Gérard/F6EEQ.

 

Prior to Zigbee adoption, Profalux roller shutter / remote communications were relying on a 868MHz protocol using rolling codes.

The most common remote, usually shipped with roller shutter, is a 3 buttons MAI-EMPX-B1 model.

Such shutters can be controlled by several remotes, each remote can be paired to several shutters. See this document (in french) for pairing a new remote to an already paired couple of roller shutter / remote.

With the help of a Flipper Zero, each of the 3 commands sent by the remote to the shutter when pressing up / down / stop can be easily captured but replaying these commands is also not an option since commands contain rolling codes protecting shutters from replay attacks.

So, the best option remains to emulate button press with a micro-controller connected to the remote.

To get Home Assitant being able to control roller shutters, remote integration to EspHome / HA is performed through 2 main steps:

• connect the remote to an ESP8266 micro-controller to emulate button press actions
• setting up an EspHome device exposing buttons, and integrate it to HA if needed.
  
  

N.B. the idea is also to keep remote as usable as before as possible, meaning that buttons could still be pressed by someone real ;-)

The following gives details about the journey.

Table of contents

• A few words about the remote
• Step 1: Figuring things out
• Step 2: Pressing remote buttons using a micro-controller.
  • Soldering a connector with GND pin
  • Connecting the ESP
  • PoC Arduino sketch
• Step 3: Making it the EspHome/HA way
  • Configuration 1: easy but with cons
  • Configuration 2: Making button pressable again
• A case, just in case ;-)

A few words about the remote

 

MAI-EMPX-B1 remote is built around a 868 MHz RF emitter and a HCS301 rolling code / modulator chip. The HCS301 chip can handle up to 4 buttons, only 3 are used here.

  A (unsoldered) 4 point connector is accessible in order to program the HCS301 chip (store keys used for KEELOQ, ...)

  A diode protect the battery against receiving current from the outside through programming connector.

By the way, in order not to destroy any existing remote, it s a good idea to search for a spare one. A brand new remote costs more or less 70 Euros but refurbished can be found for half that price.

Step 1: Figuring things out

 





The wiring of the connector can easily be reversed by testing connections with HCS301 chip as well as with buttons pads on the back side.

Pressing a button pulls input state to Vcc.

 

As the remote will be connected to a USB-powered ESP board, the battery is no longer needed.

Removing the battery however requires to shunt the protection diode. If not, RF emitter won't be supplied with power.

Step 2: pressing remote buttons using a micro-controller.

Soldering a connector with GND pin

In order to connect the remote to the ESP, GND pin has to be provided.

This can be done simply by:

• drilling a fifth connector hole besides Vcc
• soldering a 5 pin male header on the connector pads
• soldering Gnd pin to a ground location elsewhere

Connecting the ESP

The ESP used is an ESP8266-based Wemos D1 mini V3.0

Wiring is the following:

D1 mini side	Remote side
D6	Down
D7	Stop
D8	Up
3.3V	Vcc
GND	GND

PoC Arduino sketch

The following Arduino sketch can be used to check if button press are properly emulated by the ESP:

• by pairing the remote with the shutter and see if it rolls,
• by capturing traffic with a Flipper Zero (Sub-GhZ -> read / with scanning frequency set on 868MHz).

To get the D1 board working with Arduino IDE, refer to the official documentation.

#define DOWN D6
#define STOP D7
#define UP D8

#define PULSE_DELAY 500
#define WAIT_DELAY 10000

void setup() {
  pinMode(UP, OUTPUT);
  pinMode(STOP, OUTPUT);
  pinMode(DOWN, OUTPUT);
  Serial.begin(9600);
}

void pressButtonAndWait(int pin) {
  Serial.println("DOWN");
  delay(10000);
  digitalWrite(DOWN, HIGH);
  delay(500);
  digitalWrite(DOWN, LOW);
}

void loop() {
  Serial.println("DOWN");
  pressButtonAndWait(DOWN);
  Serial.println("STOP");
  pressButtonAndWait(STOP);
  Serial.println("UP");
  pressButtonAndWait(UP);
}

Step 3: Making it the EspHome/HA way

To get the D1 board running EspHome firmware, refer to Getting started section of the official documentation.

Configuration 1: easy but with cons

Configuring the EspHome device is pretty straightforward, as buttons can be considered as momentary swicthes.

The cons are nevertheless that physically pressing buttons will no longer work because since GPIO pins are configured as OUTPUT, LOW (switch OFF state) state pulls pin to GND while pressing button pulls pin to Vcc.

The resulting configuration file (only relevant sections are shown) is below:

esphome:
  name: profalux2esphome

esp8266:
  board: d1_mini_lite

# (missing elements like wifi, ... should be inserted here)
# ...
#

switch:
  - platform: gpio	
    pin: D6
    id: down
    name: "Down"
    on_turn_on:
    - delay: 500ms
    - switch.turn_off: down
    restore_mode: ALWAYS_OFF 
  - platform: gpio
    pin: D7
    id: stop
    name: "Stop"
    on_turn_on:
    - delay: 500ms
    - switch.turn_off: stop
    restore_mode: ALWAYS_OFF 
  - platform: gpio
    pin: D8
    id: up
    name: "Up"
    on_turn_on:
    - delay: 500ms
    - switch.turn_off: up
    restore_mode: ALWAYS_OFF 
  

web_server:
  port: 80

web_server section is useful only when using EspHome without HA, to be able to toogle buttons through device dashboard.

Configuration 2: Making button pressable again

In order to bring back physical buttons to life, GPIO pin mode has to be changed to INPUT when switch is in OFF state.

The resulting configuration file (only relevant sections are shown) is below:

esphome:
  name: profalux2esphome

esp8266:
  board: d1_mini_lite

# (missing elements like wifi, ... here)
...
#

substitutions:
  down_pin: 'D6'
  stop_pin: 'D7'
  up_pin: 'D8'

output:
  - platform: gpio
    pin: ${down_pin}
    id: gpio_down
  - platform: gpio
    pin: ${stop_pin}
    id: gpio_stop
  - platform: gpio
    pin: ${up_pin}
    id: gpio_up

switch:
  - platform: output
    output: gpio_down
    id: down
    name: "Down"
    on_turn_on:     
    - lambda: |-
        pinMode(${down_pin}, OUTPUT);
        digitalWrite(${down_pin}, HIGH);     
    - delay: 500ms
    - switch.turn_off: down
    on_turn_off:     
    - lambda: |-
        pinMode(${down_pin}, INPUT);       
    restore_mode: ALWAYS_OFF 

  - platform: output
    output: gpio_stop
    id: stop
    name: "Stop"
    on_turn_on:     
    - lambda: |-
        pinMode(${stop_pin}, OUTPUT);
        digitalWrite(${stop_pin}, HIGH);     
    - delay: 500ms
    - switch.turn_off: stop
    on_turn_off:     
    - lambda: |-
        pinMode(${stop_pin}, INPUT);       
    restore_mode: ALWAYS_OFF 
  
  - platform: output
    output: gpio_up
    id: up
    name: "Up"
    on_turn_on:     
    - lambda: |-
        pinMode(${up_pin}, OUTPUT);
        digitalWrite(${up_pin}, HIGH);     
    - delay: 500ms
    - switch.turn_off: up
    on_turn_off:     
    - lambda: |-
        pinMode(${up_pin}, INPUT);       
    restore_mode: ALWAYS_OFF 
  

A case, just in case ;-)

 

The original case was too thin to fit the ESP and connectors.

So, thanks to Tam who helped me to understand FreeCad basics and gave me hints to deal with it, i've made a replacement case.

Model files, in STL and STEP format, are availbale under 3D subfolder. Enjoy it!

 

Job done!
S.