Energy bill and ledserver

Last Updated or created 2022-09-26

Having a lot of devices and running a Lab wil use a lot of energy. Now with the energy crisis in Europe, i had to take a closer look at whats using power in my house.

I notished some weird usage patterns while measuring.

I’m using a few shelly power plugs, to measure devices and powerstrips.

With these devices you can control devices connected to it.
On/Off/Timer etcetera.
It wil measure the power usage in watts, and it even got a temperature sensor.
I like the fact that it perfectly integrates into your home automation using an extensive API.
curl commands to controll, and even MQTT messaging. Intergrating in Home Assistant is a breeze.

So i was monitoring a bunch of stuff using Nodered/Grafana/Homeassistant and saw some recurring usage.
But being always late to check things, i made use of my ledserver i’ve build a long time ago.

This ledserver consists of a Raspberry Pi Zero, with a led string and a API written in python.

Below is autostarted on the Raspberry

( I made this ledserver for work, it showed the status of servers and services. Beside that every colleage had a range which he could use for his own scripts. I made some little bash script templates to have led funtions standard in your bash profile.


# apt-get install python-flask

import Adafruit_WS2801
import Adafruit_GPIO.SPI as SPI
import struct

from flask import Flask, render_template, request
app = Flask(__name__)

SPI_PORT   = 0

pixels = Adafruit_WS2801.WS2801Pixels(PIXEL_COUNT, spi=SPI.SpiDev(SPI_PORT, SPI_DEVICE))


def action(deviceName, color):
        if deviceName == 'reset':
                print ("reset")
        print (deviceName)
        led = int(deviceName)
        s = color
        r = int(s[ :2], 16)
        b = int(s[2:4], 16)
        g = int(s[4: ], 16)

        pixels.set_pixel_rgb(led, r,g,b)

        templateData = {
                'rled'  : r,
                'bled'  : b,
                'gled'  : g,
                'deviceName'  : deviceName,
        return render_template('index.html', **templateData)

def actioncommand(controlcommand):
        if controlcommand == 'clear':


        templateData = {
                'controlcommand'  : controlcommand,
        return render_template('index.html', **templateData)

def rangecommand(start,stop,color):
        s = color
        r = int(s[ :2], 16)
        b = int(s[2:4], 16)
        g = int(s[4: ], 16)
        startled = int(start)
        stopled = int(stop)
        while (startled < stopled):
          pixels.set_pixel_rgb(startled, r,g,b)
          startled=startled + 1

        templateData = {
                'rangecommand'  : rangecommand,

        return render_template('index.html', **templateData)

if __name__ == "__main__":'', port=8080, debug=True)

Now you can control the leds with a simple curl command:

curl http://ledserver:8080/range/startled/endled/colorinrgb
curl http://ledserver:8080/led/lednumber/colorinrgb
curl http://ledserver:8080/control/clear

So today i made a little script to show power usage.

I’m reading the current power usage from a LS120 Youless

Youless LS120 device, which you can connect to your P1 connector.

With below bash script i’m reading the webinterface and update the ledstring.
I was using this ledserver for general notification usage. Below a 2 minute hack ..

while true; do
number=$(echo $(curl -s http://youlessip/a | grep Watt | head -1 | awk '{ print $1 }') / 100  | bc)
curl -s http://ledserver:8080/control/clear
curl -s http://ledserver:8080/range/00/$number/010101
sleep 10
Using 9 leds = 9xx watt

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