Mr-Basie
September 2, 2025, 6:42pm
1
I need to learn some stuff about wiring esp8266’s.
I want to build a controller with 5 buttons and a rotary encoder.
Hardware: Esp8266 d1 mini
First i wired without any resistors at all:
i2c:
sda: GPIO4
scl: GPIO5
scan: true
id: bus_a
pcf8574:
- id: 'pcf8574_hub'
address: 0x20
pcf8575: false
substitutions:
device_name: volume_rotary_encoder
friendly_name: Volume rotary encoder
# Button 1 = pcf8574_hub pin: 1
# Button 2 = pcf8574_hub pin: 2
# Button 3 = pcf8574_hub pin: 3
# Button 4 = pcf8574_hub pin: 4
# Button 5 = pcf8574_hub pin: 5
binary_sensor:
# VOLUME KNOB BUTTON ----------------------
- platform: gpio
pin:
number: GPIO15
#mode: INPUT_PULLUP
inverted: false
name: "${friendly_name} Volume Switch Button"
on_press:
- homeassistant.service:
service: media_player.play_pause
data:
entity_id: media_player.xxx
# Button 1 ----------------------
- platform: gpio
pin:
pcf8574: pcf8574_hub
# Use pin number 1
number: 1
mode: INPUT
inverted: false
name: "${friendly_name} Button 1"
on_press:
- logger.log: "Button 1"
- homeassistant.service:
service: media_player.play_pause
data:
entity_id: media_player.xxx
# Button 2 ----------------------
# Button 3 ----------------------
# Button 4 ----------------------
# Button 5 ----------------------
# Rotary Encoder ----------------------
sensor:
- platform: rotary_encoder
name: "${friendly_name} Rotary Encoder"
pin_b:
number: GPIO12
mode: INPUT
pin_a:
number: GPIO14
mode: INPUT
on_clockwise:
- homeassistant.service:
service: media_player.volume_set
data_template:
entity_id: media_player.xxx
volume_level: "{{ state_attr('media_player.xxx', 'volume_level') + 0.02 }}"
- logger.log: "Turned Clockwise"
on_anticlockwise:
- homeassistant.service:
service: media_player.volume_set
data_template:
entity_id: media_player.xxx
volume_level: "{{ state_attr('media_player.xxx', 'volume_level') - 0.02 }}"
- logger.log: "Turned Anti Clockwise"
After this I tried to learn how to connect the things with resistors (pull-ups).
I made this new wiring diagram. Do you think this can work?
tom_l
September 2, 2025, 11:37pm
2
No. You have connected the pull-up resistors to the wrong side of the buttons. They should connect to the side of the button that joins to your pcf8574. That way the inputs are normally high until the button is pressed then they are shorted to ground.
Also you will need:
inverted: true
for each button input.
The other way to do it is to put the resistors in the same place (on the pcf8574 side of the button) but have the other ends of the resistors connected to ground. Then have the buttons connect to 3.3V instead of ground. That way you won’t need inverted: true. There’s not really any major advantage of doing it one way or the other.
Mr-Basie
September 3, 2025, 7:05am
3
Thank you!
I have made a revised edition if you have the time to look again.
And I read that i could need a capasitor to de-couple something. Can you explain what that does?
Mr-Basie
September 3, 2025, 7:57am
5
I will try this and come back.
Mr-Basie
September 3, 2025, 8:45pm
6
Here is the final circuit. It all works fine now. Thank you @tom_l
and here is the code:
i2c:
sda: GPIO4
scl: GPIO5
scan: true
id: bus_a
pcf8574:
- id: 'pcf8574_hub'
address: 0x20
pcf8575: false
# Button 1 = pcf8574_hub pin: 1
# Button 2 = pcf8574_hub pin: 2
# Button 3 = pcf8574_hub pin: 3
# Button 4 = pcf8574_hub pin: 4
# Button 5 = pcf8574_hub pin: 5
# rotary encoder button = pcf8574_hub pin: 6
binary_sensor:
# Button 1 ----------------------
- platform: gpio
pin:
pcf8574: pcf8574_hub
# Use pin number 1
number: 1
mode: INPUT
inverted: true
name: "Button 1"
on_press:
- logger.log: "Button 1"
- homeassistant.service:
service: media_player.play_pause
data:
entity_id: media_player.xxx
# Button 2 ----------------------
- platform: gpio
pin:
pcf8574: pcf8574_hub
# Use pin number 2
number: 2
mode: INPUT
inverted: true
name: "Button 2"
on_press:
- logger.log: "Button 2"
- homeassistant.service:
service: media_player.play_pause
data:
entity_id: media_player.xxx
# Button 3 ----------------------
- platform: gpio
pin:
pcf8574: pcf8574_hub
# Use pin number 3
number: 3
mode: INPUT
inverted: true
name: "Button 3"
on_press:
- logger.log: "Button 3"
- homeassistant.service:
service: media_player.play_pause
data:
entity_id: media_player.xxx
# Button 4 ----------------------
- platform: gpio
pin:
pcf8574: pcf8574_hub
# Use pin number 4
number: 4
mode: INPUT
inverted: true
name: "Button 4"
on_press:
- logger.log: "Button 4"
- homeassistant.service:
service: media_player.play_pause
data:
entity_id: media_player.xxx
# Button 5 ----------------------
- platform: gpio
pin:
pcf8574: pcf8574_hub
# Use pin number 5
number: 5
mode: INPUT
inverted: true
name: "Button 5"
on_press:
- logger.log: "Button 5"
- homeassistant.service:
service: media_player.play_pause
data:
entity_id: media_player.xxx
# rotary encoder button -------------------
- platform: gpio
pin:
pcf8574: pcf8574_hub
# Use pin number 6
number: 6
mode: INPUT
inverted: true
name: "rotary encoder button"
on_press:
- logger.log: "rotary encoder button"
- homeassistant.service:
service: media_player.play_pause
data:
entity_id: media_player.xxx
# Rotary Encoder ----------------------
sensor:
- platform: rotary_encoder
name: "Rotary Encoder"
pin_b:
number: GPIO12
mode: INPUT
pin_a:
number: GPIO14
mode: INPUT
on_clockwise:
- homeassistant.service:
service: media_player.volume_set
data_template:
entity_id: media_player.xxx
volume_level: "{{ state_attr('media_player.xxx', 'volume_level') + 0.02 }}"
- logger.log: "Turned Clockwise"
on_anticlockwise:
- homeassistant.service:
service: media_player.volume_set
data_template:
entity_id: media_player.xxx
volume_level: "{{ state_attr('media_player.xxx', 'volume_level') - 0.02 }}"
- logger.log: "Turned Anti Clockwise"
1 Like
There isn’t an “exact” wiring diagram to follow and the reason why is, there are multiple ways to wire and use a button/switch and whichever way you choose, yyou need to make sure you configure your gpio sl that it knows what kind of Digital signal it will be watching for.
Rewarding the use of pullup/pull dowb etc is very important to understand and this concept will be used everywhere when your making circuits so, i got you something to read and i highly recommend doing that.
https://learn.sparkfun.com/tutorials/button-and-switch-basics
1 Like
No problem, just dont be late paying my bill when it comes in the mail!! ; )
