Build Instructions

Collapse

• 1

  Get Access to Control Board

  First we need to gain access to the front panel control board.

  Disconnect the power from the machine before doing anything!
  

  First, undo the two screws at the back of the dryer in order to remove the top panel. The top panel will slide forward then lift off once the two screws are removed.

  Once the top is off, there are four screws along the front of the machine that hold the front panel piece on. Undo them, then carefully pop the front panel forward a bit. Behind the panel are two wires with connectors that clip on. Grab and squeeze the clips while removing the wires. 

  Once the wires are disconnected, the whole front panel pieces comes off and can be taken elsewhere.
  

  Unclip the last wire from the control board (comes from the encoder), then you have to pop off all the clips.
  

  Finally, after a few more clips and one last screw we have access to the control board. 

• 2

  Reverse Engineering the Board

  I spent some time reverse engineering the board to figure out where to connect to. There is conformal coating which makes soldering a bit more tricky, but definitely possible.
  

  You can see the wires I ended up with. I connected to 12V, GND and RX3 (which comes from the central controller.

  You need an ESP-based board that manages to fit within the cover of the board.
  

• 3

  ESP8266 Software

  Make software in ESPHome that listens to the UART traffic and changes the state of a switch based on specific messages that happen when the dryer is first turned on or off.
  

  The code I used is based on a Custom UART Component in ESPHome and a Custom Binary Switch.

  # dryer.yaml
  esphome:
    name: dryer
    includes:
      - dryer.h
  
  esp8266:
    board: esp12e
  
  wifi:
    ssid: wifi_ssid
    password: wifi_password
  
  api:
    password: ""
  
  ota:
    password: ""
  
  logger:
    baud_rate: 0 # disable logging over uart
  
  web_server:
    port: 80
    local: true
  
  uart:
    id: uart_bus
    tx_pin: GPIO1
    rx_pin: GPIO3
    baud_rate: 38400
  
  binary_sensor:
    - platform: custom
      lambda: |-
        auto my_dryer_sensor = new DryerUartSensor(id(uart_bus));
        App.register_component(my_dryer_sensor);
        return {my_dryer_sensor};
      binary_sensors:
        name: "Dryer State"
  

  And dryer.h:
  

  // dryer.h
  #include "esphome.h"
  #include <string.h>
  
  static const uint8_t on_message[] =  {0x5a, 0xa5, 0xc0, 0x1e, 0x00, 0x00, 0x00, 0x40, 0x01, 0x00, 0x01, 0x00, 0x01, 0xe6, 0x80, 0xdb, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x23, 0x00, 0x91, 0xef};
  static const size_t on_message_len = sizeof(on_message);
  static const uint8_t off_message[] = {0x5a, 0xa5, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x52, 0x34};
  static const size_t off_message_len = sizeof(off_message);
  
  class DryerUartSensor : public Component, public UARTDevice, public BinarySensor {
      protected:
          int pos_;
          uint8_t buffer_[256];
          uint8_t dryer_state_;
      public:
      DryerUartSensor(UARTComponent *parent) : UARTDevice(parent) {}
  
      void setup() override {
      }
  
      void loop() override {
          uint8_t newData;
          int read_count = 50; //Set max read amount to prevent blocking too long
          while (this->available() && read_count--) {
              if(this->read_byte(&newData)) {
                  if((newData == 'Z') || (pos_ == 254)) {
                      if(dryer_state_) {
                          if(!memcmp(buffer_, off_message, off_message_len-2)) {
                              publish_state(false);
                              dryer_state_ = false;
                          }
                      }
                      else {
                          if(!memcmp(buffer_, on_message, on_message_len-2)) {
                              publish_state(true);
                              dryer_state_ = true;
                          }
                      }
  
                      pos_ = 0;
                  }
                  buffer_[pos_] = newData;
                  pos_ += 1;
                  buffer_[pos_] = 0;
              }
          }
      }
  };

View all 5 instructions