Lux measurement with sonoff basic?

Hardware
1

Is it possible to connect a light sensor to a sonoff basic?
To measure lux and switch lights if it gets dark?
Cant find a good solution!

1 Like
2

Iā€™m using the BH1750 (Link anchor doesnā€™t work, scroll down a bit) sensor.

Hereā€™s my config on Sonoff Basic

Auswahl_115
Auswahl_115355Ɨ629 26.9 KB

You need only SCL and SDA.

3

So you only connect two wires at the sonoff?
Does it send the lux with the sonoff mqqt?
Do you have picture of your setup?

4

The sensor needs 3.3V, ground and the 2 wires for the i2c bus. = 4 wires

Yes

No, not at the moment. But i used the RX/TX pins for SCL/SDA

5

Nice i will order one to test!

So tx is scl and Rx is Sda?

Does it send lux levels continue? Or in few minutes?

6

Not sure, i have to open the device in the evening.
But itā€™s no problem to change them, nothing getā€™s broken if they are wrong.

That depends on the TelePeriod Parameter on the Sonoff.
Minimal is 10 seconds, i think.

7

Good enough to turn on light when gets dark.
I ordered it today so tomorrow i can test it.
Hope works good!

8

Hereā€™s an issue, but also some good instruction about it.

9

I connected it and the lux level show in the sonoff menu.
How do i get the lux value in home assistant?
I thought it appears automaticly

10

You need a sensor.

sensor:
  - platform: mqtt
    name: "Sonoff01 Light"
    state_topic: "tele/sonoff01/SENSOR"
    value_template: "{{ value_json['BH1750'].Illuminance }}"
    unit_of_measurement: "lx"

The state_topic ā€˜tele/xxxxxx/SENSORā€™ depends on what you have configured in mqtt on the sonoff.

1 Like
11

It worked!
Changed the TelePeriod to lower value and now it shows the actual lux!
thanx for your help!

1 Like
12

Hi there,

This one doesnā€™t work for me for whatever reason.
I have this config:

  - platform: mqtt
   name: D1mini illuminance
   state_topic: ā€œtele/D1mini_illuminance/SENSORā€
   value_template: ā€œ{{ value_json[ 'BH1750' ].Illuminance }}ā€
   unit_of_measurement: "lx"

I run hass v0.88.0

13

Noob question! :slight_smile:

Will this work, if i connect the sensor to my sonoff as described, without changing to tasmota firmware?

As it is now, all my sonoff devices run via ewelink with standard firmware, i have different versions (with power sensors, temperature sensors, etc.), and my Hassio setup automatically detect the devices and their sensors, as soon as they have been added to Ewelink.

I know this might be a somewhat stupid presumption, but i know next to nothing about fiddling with this stuffā€¦ My thought is that the current firmware might recognize the sensor or maybe the sensor sends understandable data to the sonoff deviceā€¦

14

I donā€™t think so.
Or is it possible to configure pins, i2c, ā€¦ in Ewelink?

15

No, there are no options for configuration at all in Ewelink.

Will update to Tasmota instead! :slight_smile:

16

remember to get the ā€œtasmota-sensors.binā€ file, as this will not work with regular versions, or at least not the ones i tried at firstā€¦ :wink: