ESP8266 Lua/NodeMCU module for VEML6075 irradiance sensors

esp8266-nodemcu-veml6075 provides an ESP8266 NodeMCU Lua module (veml6075.lua) as well as MQTT / HomeAssistant / InfluxDB integration example (init.lua) for VEML6075 UV irradiance sensors connected via I²C.

Dependencies

veml6075.lua has been tested with Lua 5.1 on NodeMCU firmware 3.0.1 (Release 202112300746, float build). It requires the following modules.

• i2c

Most practical applications (such as the example in init.lua) also need the following modules.

• gpio
• mqtt
• node
• tmr
• wifi

Setup

Connect the VEML6075 sensor to your ESP8266/NodeMCU board as follows.

• VEML6075 GND → ESP8266/NodeMCU GND
• VEML6075 VCC → ESP8266/NodeMCU 3V3
• VEML6075 SDA → NodeMCU D1 (ESP8266 GPIO5)
• VEML6075 SCL → NodeMCU D2 (ESP8266 GPIO4)

If you use different pins for SCL and SDA, you need to adjust the i2c.setup call in the examples provided in this repository to reflect those changes. Keep in mind that some ESP8266 pins must have well-defined logic levels at boot time and may therefore be unsuitable for VEML6075 connection.

Usage

Copy veml6075.lua to your NodeMCU board and set it up as follows.

veml6075 = require("veml6075")
i2c.setup(0, 1, 2, i2c.SLOW)
veml6075.start()

-- can be called with up to 10 Hz
function some_timer_callback()
    if veml6075.read() then
        -- All values are float
        -- veml6075.uva   : UV-A irradiance [µW/cm²]
        -- veml6075.uvb   : UV-B irradiance [µW/cm²]
        -- veml6075.uva_i : UV-A index
        -- veml6075.uvb_i : UV-B index
    end
end

Application Example

init.lua is an example application with HomeAssistant integration. To use it, you need to create a config.lua file with WiFI and MQTT settings:

station_cfg = {ssid = "...", pwd = "..."}
mqtt_host = "..."

Optionally, it can also publish readings to InfluxDB. To do so, configure URL and attribute:

influx_url = "..."
influx_attr = "..."

Readings will be published as veml6075[influx_attr] uva_uwcm2=%f,uvb_uwcm2=%f,uv_index=%f. So, unless influx_attr = '', it must start with a comma, e.g. influx_attr = ',device=' .. device_id.