💬 Power Meter Pulse Sensor

smilvert

@gohan I think it is a little tricky to update domoticz every minute but try update the sql-file, see the domoticz forum
https://www.domoticz.com/forum/viewtopic.php?t=10183

gohan

The main issue is the fact that the sensor is not calculating the instant power correctly

DaTim69

I created this kWh sensor with the TCRT5000 IR Barrier Line Track Sensor.
My powermeter is a ferarrismeter with 375 rotations per kWh.
I also had the problem with spikes in the power usage. But after long...too long investigation I solved the problem.
At my config it was a double issue.

Issue 1.
The problem is the pulse width of the rotation.
The pulse are at night ( low power) much wider that during the day when more power is consumed. At night the spikes in power usage where huge.

Issue 2.
Switching on/off the halogen light causes spikes and related to also strange power measurement.

Solution:
I added a second arduino mini pro as a pulse regulator between the TCRT5000 and the power meter arduino.
this arduino triggers on Rising and will always give a 100ms puls. Als debounce is handled (spikes).
I don't upload the sketch here, I'm a beginning programmer on arduino. It's made on " trail and error" but it functions as it supposed to do.
If someone wants a copy feel free to contact mee

xydix

@gohan Did you solve this?
I get very high watt usage as well. Sometimes like 40 000 - 130 000 watt if I check the serial monitor.
Of course, those values will never be sent to the controler.

gohan

Nope, I am looking at other things now. Very little time available for too many things. I'm looking at buying CT clamp and do a more direct measurement.

xydix

Okay. Really annoying. Check this.

Received last pulse count from gw:2527
Watt:121065
22235 TSF:MSG:SEND,78-78-0-0,s=3,c=1,t=24,pt=5,l=4,sg=0,ft=0,st=OK:2539
22246 TSF:MSG:SEND,78-78-0-0,s=2,c=1,t=18,pt=7,l=5,sg=0,ft=0,st=OK:2.5390
Watt:121621
42238 TSF:MSG:SEND,78-78-0-0,s=3,c=1,t=24,pt=5,l=4,sg=0,ft=0,st=OK:2551
42250 TSF:MSG:SEND,78-78-0-0,s=2,c=1,t=18,pt=7,l=5,sg=0,ft=0,st=OK:2.5510
Watt:121342
62239 TSF:MSG:SEND,78-78-0-0,s=3,c=1,t=24,pt=5,l=4,sg=0,ft=0,st=OK:2563
62251 TSF:MSG:SEND,78-78-0-0,s=2,c=1,t=18,pt=7,l=5,sg=0,ft=0,st=OK:2.5630
Watt:121539
82240 TSF:MSG:SEND,78-78-0-0,s=3,c=1,t=24,pt=5,l=4,sg=0,ft=0,st=OK:2575
82251 TSF:MSG:SEND,78-78-0-0,s=2,c=1,t=18,pt=7,l=5,sg=0,ft=0,st=OK:2.5750
Watt:121951
102239 TSF:MSG:SEND,78-78-0-0,s=3,c=1,t=24,pt=5,l=4,sg=0,ft=0,st=OK:2589
102250 TSF:MSG:SEND,78-78-0-0,s=2,c=1,t=18,pt=7,l=5,sg=0,ft=0,st=OK:2.5890
Watt:122067
122243 TSF:MSG:SEND,78-78-0-0,s=3,c=1,t=24,pt=5,l=4,sg=0,ft=0,st=OK:2601
122254 TSF:MSG:SEND,78-78-0-0,s=2,c=1,t=18,pt=7,l=5,sg=0,ft=0,st=OK:2.6010

The plus count seems OK, right?

My energy meter is 1000 pluses /kwh

Here is my sketch. I use Home assistant so i created three sensors for this as I don't think V_VAR1 is supported with S_POWER.
Otherwise it is the standard example.

/**
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
 * Copyright (C) 2013-2015 Sensnology AB
 * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 *******************************
 *
 * REVISION HISTORY
 * Version 1.0 - Henrik EKblad
 *
 * DESCRIPTION
 * This sketch provides an example how to implement a distance sensor using HC-SR04
 * Use this sensor to measure KWH and Watt of your house meeter
 * You need to set the correct pulsefactor of your meeter (blinks per KWH).
 * The sensor starts by fetching current KWH value from gateway.
 * Reports both KWH and Watt back to gateway.
 *
 * Unfortunately millis() won't increment when the Arduino is in
 * sleepmode. So we cannot make this sensor sleep if we also want
 * to calculate/report watt-number.
 * http://www.mysensors.org/build/pulse_power
 */

// Enable debug prints
#define MY_DEBUG

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69
#define MY_NODE_ID 78
#include <MySensors.h>

#define DIGITAL_INPUT_SENSOR 3  // The digital input you attached your light sensor.  (Only 2 and 3 generates interrupt!)
#define PULSE_FACTOR 1000       // Nummber of blinks per KWH of your meeter
#define SLEEP_MODE false        // Watt-value can only be reported when sleep mode is false.
#define MAX_WATT 20000          // Max watt value to report. This filetrs outliers.
#define WATT_CHILD_ID 1              // Id of the sensor child
#define KWH_CHILD_ID 2
#define PC_CHILD_ID 3

unsigned long SEND_FREQUENCY =
    20000; // Minimum time between send (in milliseconds). We don't wnat to spam the gateway.
double ppwh = ((double)PULSE_FACTOR)/1000; // Pulses per watt hour
bool pcReceived = false;
volatile unsigned long pulseCount = 0;
volatile unsigned long lastBlink = 0;
volatile unsigned long watt = 0;
unsigned long oldPulseCount = 0;
unsigned long oldWatt = 0;
double oldKwh;
unsigned long lastSend;
MyMessage wattMsg(WATT_CHILD_ID,V_WATT);
MyMessage kwhMsg(KWH_CHILD_ID,V_KWH);
MyMessage pcMsg(PC_CHILD_ID,V_VAR1);


void setup()
{
  // Fetch last known pulse count value from gw
  request(PC_CHILD_ID, V_VAR1);

  // Use the internal pullup to be able to hook up this sketch directly to an energy meter with S0 output
  // If no pullup is used, the reported usage will be too high because of the floating pin
  pinMode(DIGITAL_INPUT_SENSOR,INPUT_PULLUP);

  attachInterrupt(digitalPinToInterrupt(DIGITAL_INPUT_SENSOR), onPulse, RISING);
  lastSend=millis();
}

void presentation()
{
  // Send the sketch version information to the gateway and Controller
  sendSketchInfo("Energy Meter", "1.0");

  // Register this device as power sensor
  present(WATT_CHILD_ID, S_POWER);
  present(KWH_CHILD_ID, S_POWER);
  present(PC_CHILD_ID, S_CUSTOM);
}

void loop()
{
  unsigned long now = millis();
  // Only send values at a maximum frequency or woken up from sleep
  bool sendTime = now - lastSend > SEND_FREQUENCY;
  if (pcReceived && (SLEEP_MODE || sendTime)) {
    // New watt value has been calculated
    if (!SLEEP_MODE && watt != oldWatt) {
      // Check that we dont get unresonable large watt value.
      // could hapen when long wraps or false interrupt triggered
      if (watt<((unsigned long)MAX_WATT)) {
        send(wattMsg.set(watt));  // Send watt value to gw
      }
      Serial.print("Watt:");
      Serial.println(watt);
      oldWatt = watt;
    }

    // Pulse cout has changed
    if (pulseCount != oldPulseCount) {
      send(pcMsg.set(pulseCount));  // Send pulse count value to gw
      double kwh = ((double)pulseCount/((double)PULSE_FACTOR));
      oldPulseCount = pulseCount;
      if (kwh != oldKwh) {
        send(kwhMsg.set(kwh, 4));  // Send kwh value to gw
        oldKwh = kwh;
      }
    }
    lastSend = now;
  } else if (sendTime && !pcReceived) {
    // No count received. Try requesting it again
    request(PC_CHILD_ID, V_VAR1);
    lastSend=now;
  }

  if (SLEEP_MODE) {
    sleep(SEND_FREQUENCY);
  }
}

void receive(const MyMessage &message)
{
  if (message.type==V_VAR1) {
    pulseCount = oldPulseCount = message.getLong();
    Serial.print("Received last pulse count from gw:");
    Serial.println(pulseCount);
    pcReceived = true;
  }
}

void onPulse()
{
  if (!SLEEP_MODE) {
    unsigned long newBlink = micros();
    unsigned long interval = newBlink-lastBlink;
    if (interval<10000L) { // Sometimes we get interrupt on RISING
      return;
    }
    watt = (3600000000.0 /interval) / ppwh;
    lastBlink = newBlink;
  }
  pulseCount++;
}

Anyone got any ideas?
BTW. First i tried the original example sketch, unmodified, with the same result.

gohan

That's pretty much the same problem as I have

xydix

I think i solved this.
I don't know if it is a good solution.
Maybe it is possible to solve in the code?
I added a 0,1uf ceramic capacitor between DO and GND on the LM393.
Then i tuned the LM393 until i had it blink as expected.

I think, in my case the LED pulse from my meeter was to short, it gives a very short blink.
Anyway.
I tested it all day and it seems fine now.

gohan

Are you getting instant power measurements correct?

xydix

Yes. I guess.
I don't have anything to compare with but i think it is accurate.
I have a 1000blink/kwh
Example:
Node send state every 20 sec.
pulsecount: 8 pulses every 20 sec.
Instant power in W is about 1400W

8 pulses x 3 = pulses /minute =24
24 pulses x 60 min = pulses /hour = 1440.

Edit.
Now I get a new value every 20 sec, before I didn't get any value (W) from the node at all because it was too high. I only received pulse count and kWh earlier.

gohan

Besides the cap, what exactly did you do?

xydix

Nothing more.
I use the same arduino, haven't uploaded anything new to it since i tried it last time.

What I had to do was lower the sensitivity on the LM393 because at first the signal-LED glowed a bit but when i adjusted it to lower sensitivity and closed the door to get it totaly dark the led blinked exactly as the meeter.

I have it on a bredboard and connected the cap between GND and to pin 3 so it is connected close to the arduino but i guess it shouldn't matter.

Have you tried it?

gohan

I can't believe it, IT WORKS!!!!! I added the cap directly under the pins of the LM939 board. Thanks man!

xydix

I am glad to hear it works for you too.

gohan

There is probably a sw way to correct this problem, I'll think about it

xydix

It waswhat I thought too.
As I said earlier, when I tested this my conclusion was, short blink, almost a flash will counted as a pulse (kWh) but it does something wrong with the calculation of instant power usage.
A slower blink will correct this.
My meeter gives a very short blink.

gohan

Yes, could be that a simple debounce could do the trick but I'll have to look deeper into it. @Yveaux what do you think?

gohan

@xydix Could you try to increase the 10000L to 100000L interval in the OnPulse function and see if it works without the capacitor?

user2684

I tried to build something similar and it is working nicely, thanks for sharing the idea! However, I've noticed the light sensor (alone) consumes 1mA constantly which is quite a lot when used for a battery powered project. Even if I report to the controller once per hour (summing up the power consumption along the way), still the light sensor needs to be always on, meaning I'd probably need to replace batteries after a month or so. Is there any workaround or alternative sensor which I can use or am I doing something completely wrong? Thanks

cstewy

@user2684 I had the same issue when I built this with a standalone atmega328p running on 2x AA's. I set it up with wake on interrupt from the It was constantly drawing 1.6mA to power the tsl257 to detect the flashes. My target was 1+ years on 2 x AA's. My solution to achieve this was to sleep for 125ms, wake up, send power to tsl257 to check light state (on/off), if it changed from previous reading then there was a pulse (well half pulse). By measuring every 125ms I can guarantee to capture fast pulses up to 14.4kW. (3600000/125)/2. It is 20kW max draw for residential in my country. Now:
Average mA Consumption Sleep 0.1
Average mA Consumption Wake 0.064516129
Average mA Consumption Transmit 0.002916667
Battery Life (2xAAs) = 1.7 years

💬 Power Meter Pulse Sensor

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