See your live energy use on an LED strip: WLED + HomeWizard P1

Energy dashboards are great, but nobody opens an app to check whether the dishwasher should run now. A light in the hallway that glows green when your solar panels are exporting and purple when you're importing from the grid changes behaviour in a way no chart ever did. This is a weekend project that requires zero soldering skills beyond three wires, and — thanks to browser-based flashing — zero software installation.

What do you need?

• A HomeWizard P1 meter plugged into the P1 port of your digital electricity meter (with the local API enabled in the HomeWizard app).
• An ESP32 or ESP32-C3 board (a few euros from the usual places — the flasher picks the right firmware automatically).
• An addressable LED strip, e.g. WS2812B, with an adequate 5 V supply.
• A USB data cable and a browser that supports Web Serial: Chrome or Edge on desktop.

How does flashing from the browser work?

The steefware WLED P1 Flasher uses ESP Web Tools, which talks to the ESP32 over the Web Serial API. You plug the board into USB, click Install, pick the serial port, and the browser writes a prebuilt WLED firmware with the HomeWizard P1 usermod to the chip. No Arduino IDE, no Python, no drivers hunt (on most systems), no command line.

What does the usermod actually do?

WLED is the de-facto standard firmware for addressable LEDs. The P1 usermod finds the HomeWizard P1 meter on your network automatically and reads its local REST API, mapping the current net power to a dedicated Grid Flow effect:

• Importing from the grid → purple pulses, faster as the load rises.
• Exporting solar surplus → green pulses, faster as you export more.
• Balanced → calm white.
• Everything stays local: no cloud, no account, meter data never leaves your network.

Because it is still plain WLED underneath, you keep the normal WLED app, effects, and home-automation integrations (Home Assistant discovers it automatically).

Step by step

1. Enable the Local API for your P1 meter in the HomeWizard Energy app (Settings → Meters → your meter → Local API).
2. Connect the ESP32 via USB and open the WLED P1 Flasher in Chrome or Edge.
3. Click Install, select the serial port, and wait ±2 minutes.
4. When prompted, enter your Wi-Fi credentials — they're sent over the USB cable, no hotspot dance needed.
5. Open your new WLED device, set your LED count under Config → LED Preferences. The P1 meter is discovered automatically.
6. Select the Grid Flow effect on your segment, save it as a boot preset, wire the strip, and watch your house breathe.

Troubleshooting

The browser doesn't show a serial port

Use Chrome or Edge (Firefox and Safari don't support Web Serial). Try a different USB cable — many are charge-only. On Windows, some boards need the CP210x or CH340 driver.

The strip stays dark

Verify the Local API toggle is on in the HomeWizard app, that the WLED device and the meter are on the same network, and that the Grid Flow effect is selected on your segment with the LED count configured.

Flashing fails halfway

Hold the BOOT button on the ESP32 while the connection is being made, and avoid USB hubs.

Is this safe for my meter?

Yes. The P1 port is read-only by design, and the usermod only reads the same local API the HomeWizard app itself uses.