> For the complete documentation index, see [llms.txt](https://mapir.gitbook.io/daq/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mapir.gitbook.io/daq/daq-u/using-real-time-light-measurements.md).

# Using Real-Time Light Measurements

Because the DAQ-U streams over USB-C, you can use it as a live light meter — no recording required. As soon as it is connected, Chloros applies the sensor's radiometric calibration and updates every measurement in real time.

## Live Metrics

While streaming, Chloros continuously reports the current spectrum along with the metrics derived from it:

* Spectral irradiance power (W/m²·nm) and total irradiance (W/m²)
* PAR / PPFD (µmol/m²/s) for plant-growth lighting
* Photometric illuminance (lux)
* Color metrics — CCT (K), CRI, and CIE coordinates

This makes the DAQ-U useful for checking a light source, comparing fixtures, or confirming that outdoor conditions are stable before a flight or a scan.

## Real-Time Reflectance

Pair the DAQ-U with a MAPIR [LATTICE camera](https://www.mapir.camera/pages/multispectral-cameras) to calibrate reflectance live during capture, or use a second DAQ sensor to read the ambient light while the DAQ-U reads an object — reflectance is then updated continuously as the ambient light changes, with no need to stop and scan a reference target. See [Using Multiple DAQ-U](/daq/daq-u/using-multiple-daq-u-together.md).

{% hint style="info" %}
For how to open the live view and configure real-time streaming in the software, see the Chloros Manual at [docs.chloros.com](https://docs.chloros.com) *(link coming soon)*.
{% endhint %}