Unknown MCU in VOXX Mod1. Is it ESP?

Hardware
1

20230220_222154
20230220_2221541920×1440 350 KB

Does anyone recognize this? I’m hoping to convert it to ESPHOME but I’m not sure if that’s possible without replacing the MCU. There’s a convenient serial header but esptool can’t connect. Any suggestions on how to identify GPIO0 so I can pull it low and see if that let’s esptool see it?

Thanks!

2

Try holding down the reset button when you power it up.

3

Remove the metal cover and see what’s the chip underneath?

4

Thanks for the replies.

The reset button doesn’t seem to be connected to the MCU’s reset pin. When I apply power through the header I get output like the following:

Boot from ROMv3
R>INFO:PKG=0x4c49
INFO:sdio_init() tx_start 0x4e1d0 size 0x800 rx_start 0x4e9d0 size 0x800 align_size 40
INFO:sdio_init() vid 0x188 pid 0x6700
INFO:sdio_init() CCCR_CIS_AREA_BASE 0x4f1d0
INFO:sdio_init done!!

Pressing the reset button doesn’t result in any additional logging and applying power while holding the reset button shows the same output. ESPTool can’t connect either way.

As for removing the cover, does it just pry off or do I need to blast it with hot air or something?

5

It will likely be soldered on.

6

A little heat and gentle prying got it to come up.

20230221_182356
20230221_1823561920×1440 394 KB

I’m guessing I’m out of luck. That’s a Montage Technology chip. I found the manual registered with the FCC https://fccid.io/2AEDFWM6800K/User-Manual/User-Manual-3503146 so I guess I’ll go through that to see if I can figure out how to replace it with an ESP.

7

In case anyone else also has a MyGuard Smart Automatic Laundry Shut Off System by RCA and wants to integrate it with HA, I ended up not using the included Mod1 at all. I added a Wemos D1 mini and a level shifter to the main unit and hooked up the following through the level shifter:
Test/Reset button to D1 (the side that’s not grounded)
The output to the valve on led to D5 (before the current limiting resistor)
The output to the moisture led to D7 (before the current limiting resistor)
The unit has an unpopulated debug header that provides GND and 5V
Here is the code I wrote and it’s working well so far:

esphome:
  name: washer-shutoff
  friendly_name: Washer Shutoff

esp8266:
  board: d1_mini

# Enable logging
logger:

# Enable Home Assistant API
api:
  encryption:
    key: ""

ota:
  password: ""

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Washer-Shutoff Fallback Hotspot"
    password: ""

captive_portal:

#D1 as test button output open_drain 
output:
  - platform: gpio
    pin:
      number: D1
      inverted: True
      mode:
        output: True
        open_drain: True
    id: gpio_d1
    
    
cover:
  - platform: template
    name: Washer Valve
    lambda: |-
      if (id(wash_valve_status).state) {
        return COVER_OPEN;
      } else {
        return COVER_CLOSED;
      }
    open_action:
      - output.turn_on: gpio_d1
      - delay: 500ms
      - output.turn_off: gpio_d1
    close_action:
      - output.turn_on: gpio_d1
      - delay: 3100ms
      - output.turn_off: gpio_d1

binary_sensor:
  - platform: gpio
    pin:
      number: D5
      inverted: False
    id: wash_valve_status
    name: "Washer Valve Status"
    device_class: opening
  - platform: gpio
    pin:
      number: D7
      inverted: False
    name: "Washer Moisture Alarm"
    icon: "mdi:water_alert"
    device_class: moisture