The Smarter.am cloud service is (for all intents and purposes) dead. AFAIK, all Smarter products are therefore no longer ‘smart’. Long live ESPHome!
With help from the information in this guide, I’ve successfully converted my Smarter iKettle 3.0 to ESP32/ESPHome. My project is a bit more ambitious. I’ve completely replaced the logic board within the iKettle 3.0, and have attempted to replicate all of its functions (with one exception), including:
- No change to appearance/no additional wires
- Retain original power button and power LED
- RGB LED to show WiFi connection status
- HX711 to read the load cell to weigh the kettle to estimate fill level
- Buzzer to indicate turn on/off or on error
- Connect to and read kettle thermistor for auto-off/thermostatic control
I haven’t bothered trying to replicate the light sensor/LDR that interprets flashes from your phone’s screen to upload WiFi connection details for initial setup.
DISCLAIMER: Probably don’t do this. I’m no expert. I’m scraping by with an electronics GCSE from 1999, ChatGPT, a multimeter, basic soldering iron and awareness of the potential dangers. That said, such a disclaimer wouldn’t have stopped me, so I’m sharing my work for likeminded people.
Opening up the iKettle base, you’ll find a 3-wire connector joining the power board and the logic board. These three wires are a 5v supply, GND and connection to the positive side of the relay coil. Bridging the 5v and relay control wires causes the relay to click on and would provide power to the kettle element.
So, safety aside, this is a pretty easy conversion. We can leave the power board alone, and build something that can read the kettle temp and connect 5v to the relay control wire to turn on/disconnect to turn off.
Parts list:
- ESP32-S3 Mini
- HX711 ADC/pressure sensor to measure weight
- RGB LED (common cathode) for status indication
- White LED for power indication
- Active buzzer for the beep
- PN2222 transistor
- 104pF ceramic cap
- 3 x 330 ohm resistors
- 1 x 47k resistor for the thermistor (10k might be better - not sure)
- Right angle push button
- JST-XH connector kit
- Assorted multicoloured wire
Tools:
- Soldering iron
- Philips screwdriver
- Wire strippers
- Multimeter (to check continuity across joined connections/voltages)
- 2.54mm crimp tool
- Dremel to cut perf board
- Thermometer (to read water temp and tune the thermistor values accordingly)
I started by attempting to cut a perf board to roughly the same shape as the original iKettle logic board:
I then attempted to situate the components in the only way I could get them all to fit. I had to sacrifice one of the screw holes by the status LED, and had to cut the standoff to make room for my new board.
I’ve neglected to take a photo of the underside of my board, but honestly that wouldn’t necessarily help because it’s a bit of a mess.
Here’s what my board looks like installed. I soldered JST-XH connectors onto the board for the connection to the power board, HX711 and thermistor so that it can be removed easily. The load cell and resistors required to create a ‘half bridge’ (see diagram) are soldered to the HX711 itself:
The HX711 is just kinda placed inside, unsecured.
Ignore the second transistor next to the buzzer. It’s not needed.
Here’s my circuit diagram:
Note that the thermistor is not on the board, it’s inside the kettle itself. On the board I have a 2-pin HX-2A connector, which re-uses the existing connector. The same applies to the 5v/GND/Relay connections - I’ve soldered an HX-3A to the board and am re-using the existing connector.
…and here’s my YAML:
esphome:
name: smart_kettle
friendly_name: "Smart Kettle"
on_boot:
priority: -100
then:
- script.execute: boot_led_sequence
esp32:
board: esp32-s3-devkitc-1
framework:
type: arduino
logger:
level: info
api:
encryption:
key: !secret api_key
ota:
- platform: esphome
password: !secret ota_password
wifi:
ssid: !secret wifi_ssid
password: !secret wifi_password
on_connect:
then:
- script.execute: wifi_connected
captive_portal:
web_server:
port: 80
status_led:
pin: GPIO48
globals:
- id: kettle_on
type: bool
restore_value: no
initial_value: "false"
switch:
- platform: gpio
id: rgb_red
pin: GPIO6
internal: true
- platform: gpio
id: rgb_green
pin: GPIO5
internal: true
- platform: gpio
id: rgb_blue
pin: GPIO4
internal: true
- platform: gpio
id: power_led
pin: GPIO10
internal: true
- platform: gpio
id: buzzer
pin: GPIO12
internal: true
- platform: gpio
id: relay
pin: GPIO13
restore_mode: ALWAYS_OFF
internal: true
on_turn_on:
- globals.set:
id: kettle_on
value: "true"
- script.execute: relay_safety_timer
on_turn_off:
- globals.set:
id: kettle_on
value: "false"
- switch.turn_off: power_led
- platform: template
name: "Smart Kettle"
icon: mdi:kettle
lambda: |-
return id(kettle_on);
turn_on_action:
- script.execute: kettle_on_request
turn_off_action:
- script.execute: kettle_off_sequence
binary_sensor:
- platform: gpio
id: power_button
pin:
number: GPIO11
mode: INPUT_PULLUP
inverted: true
on_press:
- script.execute: kettle_toggle_request
- platform: template
id: kettle_on_base
name: "Kettle On Base"
lambda: |-
return id(load_cell).state < -80000;
on_release:
then:
- if:
condition:
lambda: 'return id(kettle_on);'
then:
- script.execute: kettle_off_sequence
sensor:
- platform: hx711
id: load_cell
name: "Load Cell"
dout_pin: GPIO7
clk_pin: GPIO8
update_interval: 200ms
filters:
- median:
window_size: 7
send_every: 3
unit_of_measurement: "g"
accuracy_decimals: 0
internal: true
- platform: template
name: "Kettle Fill Percentage"
lambda: |-
float w = id(load_cell).state;
float pct = (w + 119000.0) / (-445000.0 + 119000.0) * 100.0;
if (pct < 0) pct = 0;
if (pct > 100) pct = 100;
return pct;
unit_of_measurement: "%"
update_interval: 2s
- platform: adc
pin: GPIO9
id: adc_ntc
attenuation: 11db
update_interval: 2s
- platform: resistance
id: ntc_res
sensor: adc_ntc
resistor: 47kOhm
configuration: DOWNSTREAM
- platform: ntc
id: kettle_temp_raw
sensor: ntc_res
calibration:
b_constant: 3931
reference_resistance: 50.9kOhm
reference_temperature: 25
- platform: template
id: kettle_temp
name: "Kettle Temperature"
lambda: |-
return (id(kettle_temp_raw).state + 16.7) * (85.8 / 67.7) + 14.2;
unit_of_measurement: "°C"
accuracy_decimals: 1
update_interval: 2s
filters:
- lambda: |-
if (x < 0 || x > 120) return NAN;
return x;
- sliding_window_moving_average:
window_size: 5
send_every: 1
on_value:
then:
- if:
condition:
lambda: 'return x >= 100.0 && id(kettle_on);'
then:
- script.execute: kettle_off_sequence
script:
- id: kettle_toggle_request
then:
- if:
condition:
lambda: 'return id(kettle_on);'
then:
- script.execute: kettle_off_sequence
else:
- script.execute: kettle_on_request
- id: kettle_on_request
then:
- if:
condition:
and:
- binary_sensor.is_on: kettle_on_base
- lambda: 'return id(kettle_temp).state < 100.0;'
then:
- switch.turn_on: relay
- switch.turn_on: power_led
- switch.turn_on: buzzer
- delay: 200ms
- switch.turn_off: buzzer
else:
- script.execute: error_beep
- id: relay_safety_timer
mode: restart
then:
- delay: 120s
- if:
condition:
lambda: 'return id(kettle_on);'
then:
- script.execute: kettle_off_sequence
- id: kettle_off_sequence
then:
- switch.turn_off: relay
- switch.turn_off: power_led
- repeat:
count: 3
then:
- switch.turn_on: buzzer
- delay: 250ms
- switch.turn_off: buzzer
- delay: 250ms
- id: error_beep
then:
- repeat:
count: 5
then:
- switch.turn_on: buzzer
- delay: 250ms
- switch.turn_off: buzzer
- delay: 250ms
- id: boot_led_sequence
mode: restart
then:
- while:
condition:
not:
wifi.connected:
then:
- switch.turn_on: rgb_blue
- delay: 250ms
- switch.turn_off: rgb_blue
- delay: 250ms
- id: wifi_connected
then:
- switch.turn_off: rgb_blue
- switch.turn_on: rgb_green
For testing, you’ll want to set comment out the ‘internal: true’ lines so that all the controls/sensor values will be displayed on the web portal for testing/tuning, and then you can update the YAML accordingly. To tune the load cell and thermistor readings, paste the YAML into ChatGPT and say ‘help me to correct these sensor values’, and provide the readings when the kettle is on/off the base, empty versus full, room temp water versus boiling, etc.), it’ll do the work for you.
There are no doubt many improvements that could be made to the code. Feel free to let me know.
I spent a good few days on this, all so I can once again control my kettle via HA/Alexa. Was it worth it? Of course!