Multiple Devices With One UART

ESPHome
1

Is it possible to connect more devices to one bus uart line?
So how is this possible with i2c?
Is a pullup resistor needed on RX and TX?

I want to connect a pm1006 from ikea and a mhz-19 CO2 sensor to one line, is this possible?
Thanks

2

A UART is not a bus, it’s a point to point link.

Because I2C is an addressable bidirectional bus.

No.

No.

1 Like
3

Well thank you. Then it is necessary to define 2 separate uarts.

uart:
  - id: uart2
    rx_pin: "$uart2_rx_pin"
    tx_pin: "uart2_tx_pin"
    baud_rate: 9600
  
  - id: uart1
    rx_pin: "$uart_rx_pin"
    tx_pin: "$uart_tx_pin"
    baud_rate: 9600

sensor:
#-------------------------------------------
# CO2 sensor - MHZ19
#-------------------------------------------
  - platform: mhz19
    co2:
      name: "${friendly_name} CO2"
    temperature:
      name: "${friendly_name} Temperature CO2"
    update_interval: "never"
    automatic_baseline_calibration: true
    uart_id: uart1
    id: mhz19_co2

#-------------------------------------------
# IKEA VINDRIKTNING Particulate Matter Sensor with PM1006 inside
# pm 2.5
#-------------------------------------------
  - platform: pm1006
    pm_2_5:
      name: "${friendly_name} PM2.5"
      filters:
      - median:
          window_size: 7
          send_every: 4
          send_first_at: 3
    update_interval: 320s
    uart_id: uart2

It is correct?

4

You will need two separate UARTs, yes.

I don’t know how to define them in ESPHome, I don’t use it.

1 Like