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* e.g. to e.g., and proper case for Home Assistant * Instructions how to -> Instructions on how to
106 lines
3.9 KiB
Markdown
106 lines
3.9 KiB
Markdown
---
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layout: page
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title: "BH1750 Light sensor"
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description: "Instructions on how to integrate a BH1750 light sensor into Home Assistant."
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date: 2017-06-10 00:00
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sidebar: true
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comments: false
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sharing: true
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footer: true
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logo: raspberry-pi.png
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ha_category: Sensor
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ha_release: 0.48
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ha_iot_class: "Local Push"
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---
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The `bh1750` sensor platform allows you to read the ambient light level in Lux from a [BH1750FVI sensor](http://cpre.kmutnb.ac.th/esl/learning/bh1750-light-sensor/bh1750fvi-e_datasheet.pdf) connected via [I2c](https://en.wikipedia.org/wiki/I²C) bus (SDA, SCL pins). It allows you to use all the resolution modes of the sensor described in its datasheet.
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Tested devices:
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- [Raspberry Pi](https://www.raspberrypi.org/)
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To use your BH1750 sensor in your installation, add the following to your `configuration.yaml` file:
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```yaml
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# Example configuration.yaml entry
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sensor:
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- platform: bh1750
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```
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Configuration variables:
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- **name** (*Optional*): The name of the sensor
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- **i2c_address** (*Optional*): I2c address of the sensor. It is 0x23 or 0x5C.
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- **i2c_bus** (*Optional*): I2c bus where the sensor is. Defaults to 1, for Raspberry Pi 2 and 3.
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- **operation_mode** (*Optional*): Working mode for the sensor. Defaults to `continuous_high_res_mode_1` for continuous measurement and 1 lx resolution.
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- **measurement_delay_ms** (*Optional*): Delay time in ms for waiting the sensor to get the measure. Defaults to 120 ms.
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- **multiplier** (*Optional*): Correction coefficient to multiply the measured light level. Value between 0.1 and 10. Default is 1.
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## {% linkable_title Full Examples %}
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If you want to specify the resolution mode of the digital sensor or need to change the default I2c address (which is 0x23), add more details to the `configuration.yaml` file.
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The sensor can work with resolutions of 0.5 lx (high res mode 1), 1 lx (high res mode 2) or 4 lx (low res mode), and make measurements continuously or one time each call. To set any of these operation modes, select one of these combinations: `continuous_low_res_mode`, `continuous_high_res_mode_2`, `continuous_high_res_mode_1`, `one_time_high_res_mode_1`, `one_time_high_res_mode_2`, `one_time_low_res_mode`.
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```yaml
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# Example of customized configuration.yaml entry
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sensor:
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- platform: bh1750
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name: Ambient light
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i2c_address: 0x5C
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operation_mode: one_time_high_res_mode_1
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measurement_delay_ms: 200
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scan_interval: 25
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```
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## {% linkable_title Directions for installing smbus support on Raspberry Pi %}
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Enable I2c interface with the Raspberry Pi configuration utility:
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```bash
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# pi user environment: Enable i2c interface
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$ sudo raspi-config
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```
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Select `Interfacing options->I2C` choose `<Yes>` and hit `Enter`, then go to `Finish` and you'll be prompted to reboot.
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Install dependencies for use the `smbus-cffi` module and enable your _homeassistant_ user to join the _i2c_ group:
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```bash
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# pi user environment: Install i2c dependencies and utilities
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$ sudo apt-get install build-essential libi2c-dev i2c-tools python-dev libffi-dev
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# pi user environment: Add homeassistant user to the i2c group
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$ sudo addgroup homeassistant i2c
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# pi user environment: Reboot Raspberry Pi to apply changes
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$ sudo reboot
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```
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### {% linkable_title Check the i2c address of the sensor %}
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After installing `i2c-tools`, a new utility is available to scan the addresses of the connected sensors:
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```bash
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$ /usr/sbin/i2cdetect -y 1
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```
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It will output a table like this:
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```text
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0 1 2 3 4 5 6 7 8 9 a b c d e f
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00: -- -- -- -- -- -- -- -- -- -- -- -- --
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10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
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20: -- -- -- 23 -- -- -- -- -- -- -- -- -- -- -- --
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30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
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40: 40 -- -- -- -- -- UU -- -- -- -- -- -- -- -- --
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50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
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60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
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70: -- -- -- -- -- -- -- 77
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```
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So you can see the sensor address what you are looking for is **0x23** (there are more i2c sensors in that Raspberry Pi).
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