My DIY smart meter

[MikeF]

Not being a fan of (UK) smart meters (the first generation ones go 'dumb' if you switch energy supplier, and I don't like the idea of the meters 'phoning home' to the supplier all the time), I decided to build my own.

My electricity meter incorporates a LED which flashes once per kWh, and my gas meter has a small magnet in the least significant digit dial, which corresponds to 1/100 m3 per revolution. Using this post as inspiration: https://www.domoticz.com/forum/viewtopi ... 32&t=11315, I am using an opto-sensor like this: https://www.ebay.co.uk/itm/371350785169 ... EBIDX%3AIT and a reed switch sensor like this: https://www.ebay.co.uk/itm/Reed-Sensor- ... Sw6CJbEYRS, connected to the GPIO of a RPi Zero WH, which runs a python script to send meter data to Domoticz.

Below are pictures of the 2 sensors mounted in small plastic cases, and fixed to the meters with Blu Tack (not fallen off yet!):



I have set up devices in the Utility tab in Domoticz to display electricity and gas usage, and I've also created a number of custom and text sensors to display calculated information: energy (in kWh), cost (using rates from my supplier), and meter readings (these last are incremented by the python script, and over the course of a month have remained very close to the actual meter readings which I read periodically to send to my supplier).



By clicking on the Log button on the cost devices, I can view cost history over the last month:



Finally, as the pièce de resistance, I have set up a meter display in ImperiHome (via MyDomoAtHome), which I run on a Samsung Android tablet:

[MikeF]

I'm attaching below the 2 scripts I use to drive the above setup.

1. Python script to read meter pulses and send to Domoticz

This is based on RidingTheFlow's script (see first post); I have modified it so that I can input actual meter readings when it is first run (and I rerun it periodically, to 'calibrate' it). It uses the RPi gpiozero library. I run it in the background using screen. Replace the Domoticz url / port and idx's with your own values. GPIO pins 17 and 24 are used here for the gas and electricity counters respectively.

Spoiler: show

Code: Select all

#!/usr/bin/env python

'''
Based on https://www.domoticz.com/forum/viewtopic.php?f=32&t=11315
by RidingTheFlow

'''

import time, datetime
import json
import urllib2
import requests
import threading
import os
from gpiozero import DigitalInputDevice
import sys

init_elec = float(input("Elec meter reading: "))
init_gas  = float(input("Gas  meter reading: "))

get_url = 'http://<Domoticz url:port>/json.htm?type=devices&rid=%s'
set_url = 'http://<Domoticz url:port>/json.htm?type=command&param=udevice&idx=%s&svalue=%s'
gas_delta = 0
gas_idx = <xxx>
gas_gpio = 17
gas_counter_lock = threading.Lock()
elec_delta = 0
elec_idx = <xxx>
elec_gpio = 24
elec_counter_lock = threading.Lock()
elec_last_time = 0
elec_post_time = 0
init = True
elec_meter_idx = <xxx>
gas_meter_idx = <xxx>

def gas_intr():
    global gas_delta
    with gas_counter_lock:
        gas_delta += 10

def elec_intr():
    tme = time.time()
    global elec_delta
    global elec_last_time
    global elec_post_time
    with elec_counter_lock:
        elec_last_time = tme
        if elec_post_time == 0:
            elec_post_time = elec_last_time
        else:
            elec_delta += 1
    
def main():
    global gas_delta
    global gas_counter
    global elec_delta
    global elec_last_time
    global elec_post_time
    global elec_counter
    global init
    global init_elec
    global init_gas

    res = json.load(urllib2.urlopen(get_url % elec_idx))

    elec_counter = int(float(res['result'][0]['Data'][:-4]) * 1000)
    if init:
    	elec_counter = init_elec * 1000
    	print
    	print "Initial elec meter reading: ", datetime.datetime.now().strftime("%a %b %d %H:%M:%S"), init_elec
    	#init = False

    res = json.load(urllib2.urlopen(get_url % gas_idx))

    gas_counter = int(float(res['result'][0]['Data']) * 1000)
    if init:
    	gas_counter = init_gas * 1000
    	print "Initial gas  meter reading: ", datetime.datetime.now().strftime("%a %b %d %H:%M:%S"), init_gas
    	init = False

    elecSensor = DigitalInputDevice(elec_gpio, pull_up=True)
    elecSensor.when_deactivated = elec_intr

    gasSensor = DigitalInputDevice(gas_gpio, pull_up=True)
    gasSensor.when_activated = gas_intr  
    
    #os.nice(-20)

    while True:
        time.sleep(60)

        gas_delta_post = gas_delta

        if gas_delta_post >= 0:
            gas_counter += gas_delta_post
            with gas_counter_lock:
                gas_delta -= gas_delta_post
            meter  = format(gas_counter / 1000.0, '.3f') + "%20m3" # text sensor
            res = requests.get(set_url % (gas_idx, gas_counter))
            res = requests.get(set_url % (gas_meter_idx, meter))

        with elec_counter_lock:
            if elec_last_time > elec_post_time:
                elec_load = elec_delta * 3600 / ( elec_last_time - elec_post_time )
            else:
                elec_load = 0

            elec_counter += elec_delta
            meter  = format(elec_counter / 1000.0, '.2f') + "%20kWh" # text sensor

            elec_delta = 0
            elec_post_time = elec_last_time

        if elec_load != 0:
            res = requests.get((set_url+';%s') % (elec_idx, int(elec_load), elec_counter))
            res = requests.get((set_url) % (elec_meter_idx, meter))

if __name__=="__main__":
    main()  

2. dzVents script to calculate electricity and gas energy (in kWh) and costs. Change device names and cost rates to your own values.

Spoiler: show

Code: Select all

-- dzVents script to calculate electricity and gas costs

return {
    on = { timer   = { "every minute" }}, 

    execute = function(dz)
        -- devices
        local elecUsage     = dz.devices("Electricity usage").counterToday
        local elecCost	    = dz.devices("Electricity cost")
        local elecEnergy    = dz.devices("Electricity energy")
        local gasUsage		= dz.devices("Gas usage").counterToday
        local gasCost		= dz.devices("Gas cost")
        local gasEnergy		= dz.devices("Gas energy")
        local totalCost		= dz.devices("Total cost")
        
        -- prices in pence
        local elecStdChge = 20.44
        local elecUnitPrice  = 13.587
        local m3_kWh = 1.02264 * 39.3 / 3.6 -- conversion factor x calorific value / kWh
        local gasStdChge = 20.44
        local gasUnitPrice = 3.371
        
        -- calculate values
        local elecCostVal	= dz.utils.round((elecUsage * elecUnitPrice + elecStdChge),1)   -- rounded to 1 dp
        local elecUsageVal	= dz.utils.round(elecUsage,3)            	                  -- rounded to 3 dp's
        local gasCostVal   	= dz.utils.round((gasUsage * m3_kWh * gasUnitPrice + gasStdChge),1)   -- rounded to 1 dp
        local gasEnergyVal  = dz.utils.round((gasUsage * m3_kWh),3)  -- rounded to 3 dp's
        local totalCostVal  = elecCostVal + gasCostVal
        --print(elecCostText, gasCostText, totalCostText)

        -- update devices
        elecCost.updateCustomSensor(elecCostVal)
        elecEnergy.updateCustomSensor(elecUsageVal)
        gasCost.updateCustomSensor(gasCostVal)
        gasEnergy.updateCustomSensor(gasEnergyVal)
        totalCost.updateCustomSensor(totalCostVal)
    
    end
}

[mgerhard74]

Cool! A friend of me designed a ESP8266 reader to get data via Wifi from our NETZ OÖ Siemens TD-3511 smartmeters:

amis.jpg (67.74 KiB) Viewed 4754 times

amisapi.jpg (22.95 KiB) Viewed 4754 times

Data can be read by a small LUA script or sent by MQTT.

[Jinja1l]

Cool! A friend of me designed a ESP8266 reader to get data via Wifi from our NETZ OÖ Siemens TD-3511 smartmeters:

amis.jpg

amisapi.jpg

Data can be read by a small LUA script or sent by MQTT.

Really professional looking board.
Any change you could share schematics of the reader?

[mgerhard74]

Hi Jinja1l ,
this Amis-Reader project is "open source". So we share schematics, PCB (Eagle files) and sourcecode (soon) at my webpage: http://www.mitterbaur.at/amis-leser.html (sorry only in german)
lg
Gerhard

[Jinja1l]

Awesome, thank you!
Would it be possible to share also source code?

[mgerhard74]

source code added to downloads.

[Jinja1l]

source code added to downloads.

Sorry but I cannot find it. Link?

[Jinja1l]

Maybe I just forgot to reload the page. Source code is there now. Thank you!