SEN55 is found during scan but says communication failed?

ESPHome
1

I’m trying to use a SEN5x device (SEN55) with a Raspberry Pi Pico W and it isn’t working.
Would love some help figuring out what’s wrong!

In the logs, the I2C bus scan finds it, but then says communication failed:

[22:35:33][I][i2c.arduino:068]: Results from i2c bus scan:
[22:35:33][I][i2c.arduino:074]: Found i2c device at address 0x69
[22:35:33][C][sen5x:227]: sen5x:
[22:35:33][C][sen5x:228]:   Address: 0x69
[22:35:33][W][sen5x:232]: Communication failed! Is the sensor connected?

I’ve tried the sensor with a regular Raspberry Pi 3 using the sample here:

…and it works fine, so I know the device works.

My wiring is:
VDD: SEN5x pin 1 to Pico pin 40 (5V from USB)
GND: SEN5x pin 2 to Pico pin 38
SDA: SEN5x pin 3 to Pico pin 26 (GPIO20)
SCL: SEN5x pin 4 to Pico pin 27 (GPIO21)
SEL: SEN5x pin 5 to Pico pin 38

Here’s my yaml:

esphome:
  name: pico-w-2c16

rp2040:
  board: rpipicow
  framework:
    # Required until https://github.com/platformio/platform-raspberrypi/pull/36 is merged
    platform_version: https://github.com/maxgerhardt/platform-raspberrypi.git

# Enable logging
logger:

# Enable Home Assistant API
api:
  encryption:
    key: "[redacted]"

ota:
  safe_mode: false
  password: "[redacted]"

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

substitutions:
  name: Indoor

i2c:
  sda: GPIO20
  scl: GPIO21
  scan: true
  id: i2c_a

.defaultfilters:
  - &moving_avg
    sliding_window_moving_average:
        window_size: 6
        send_every: 3

sensor:
  - platform: sen5x
    id: sen55
    pm_1_0:
      name: "${name} PM <1µm Weight concentration"
      id: pm_1_0
      accuracy_decimals: 2
      filters: [ *moving_avg ]
    pm_2_5:
      name: "${name} PM <2.5µm Weight concentration"
      id: pm_2_5
      accuracy_decimals: 2
      filters: [ *moving_avg ]
    pm_4_0:
      name: "${name} PM <4µm Weight concentration"
      id: pm_4_0
      accuracy_decimals: 2
      filters: [ *moving_avg ]
    pm_10_0:
      name: "${name} PM <10µm Weight concentration"
      id: pm_10_0
      accuracy_decimals: 2
      filters: [ *moving_avg ]
    temperature:
      name: "${name} Temperature 2"
      accuracy_decimals: 2
      filters: [ *moving_avg ]
    humidity:
      name: "${name} Humidity 2"
      accuracy_decimals: 2
      filters: [ *moving_avg ]
    voc:
      name: "${name} VOC"
      filters: [ *moving_avg ]
      algorithm_tuning:
        index_offset: 100
        learning_time_offset_hours: 12
        learning_time_gain_hours: 12
        gating_max_duration_minutes: 180
        std_initial: 50
        gain_factor: 230
    nox:
      name: "${name} NOx"
      id: nox
      filters: [ *moving_avg ]
    temperature_compensation:
      offset: 0
      normalized_offset_slope: 0
      time_constant: 0
    acceleration_mode: low
    store_baseline: true
    address: 0x69
    update_interval: 10s
2

I had the same issue, and I think it was EM interference in the long wires to the sensor. Reducing the I2C frequency seems to have fixed it:

i2c:
    scan: true                                                                                                                            
    frequency: 10kHz
3

In my case I used pin 19 GND on the esp32 and for some reason its not true ground. Switched to GND that is the very last pin on the opposite side and that worked.
But I do get this…
[00:15:42][W][component:214]: Component sen5x.sensor took a long time for an operation (0.08 s).
[00:15:42][W][component:215]: Components should block for at most 20-30ms.