Home Assistant, add an offset to a sensor output?

Forums › Gadgets, robotics, home automation, electronics (including wearables) › Home Assistant, add an offset to a sensor output?

peejayw

1841 posts

Uber Geek

#289841 2-Oct-2021 15:51

I made a small "weather station" from a Wemos D1 mini and a BME280 sensor to get temperature, pressure and humidity data. It works well but I would rather see the pressure adjusted for sea level rather than the absolute pressure that the sensor provides. At my elevation I need to add 25 hPa to the reading. I dont think this can be done on the sensor itself but is there a way to do it within the card display?

This is what I am using.....

entities:
- sensor.bme280_pressure
group_by: hour
hour24: true
name: Pressure
show:
fill: fade
type: custom:mini-graph-card

Thanks.

I'm supposed to respect my elders, but it's getting harder and harder for me to find one now.

mattenz

190 posts

Master Geek

#2788296 2-Oct-2021 15:58

Are you using ESPHome? I would have thought that it would be easier to do it in that.

hairy1

3332 posts

Uber Geek

ID Verified

Trusted

Lifetime subscriber

#2788298 2-Oct-2021 16:00

Just make a template sensor based on the original sensor and reference that.

My views (except when I am looking out their windows) are not those of my employer.

peejayw

1841 posts

Uber Geek

#2788300 2-Oct-2021 16:07

mattenz:

Are you using ESPHome? I would have thought that it would be easier to do it in that.

Yes I am as follows...

esphome:
name: temperature-pressure-humidity
platform: ESP8266
board: d1_mini

# Enable logging
logger:

# Enable Home Assistant API
api:

ota:
password: "747106162569653ff5a4ed986b09f717"

wifi:
ssid: "xxx"
password: "yyy"

# Enable fallback hotspot (captive portal) in case wifi connection fails
ap:
ssid: "Temperature-Pressure-Humidity"
password: "zvdKZDJHPQfU"

captive_portal:

i2c:
# sda: 21
# scl: 22
scan: true
id: bus_a

sensor:
- platform: bme280
temperature:
name: "BME280 Temperature"
oversampling: 16x
pressure:
name: "BME280 Pressure"
humidity:
name: "BME280 Humidity"
update_interval: 60s
i2c_id: bus_a
address: 0x76

Where would I apply the offset here?

Thanks.

I'm supposed to respect my elders, but it's getting harder and harder for me to find one now.

peejayw

1841 posts

Uber Geek

#2788301 2-Oct-2021 16:08

hairy1: Just make a template sensor based on the original sensor and reference that.

OK, not really sure what that all means but will look into it, thanks.

I'm supposed to respect my elders, but it's getting harder and harder for me to find one now.

mattenz

190 posts

Master Geek

#2788302 2-Oct-2021 16:08

You can add an offset, see:

https://esphome.io/components/sensor/index.html#offset

peejayw

1841 posts

Uber Geek

#2788320 2-Oct-2021 16:28

Perfect! Thanks for that, all working now.

I'm supposed to respect my elders, but it's getting harder and harder for me to find one now.