Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Energy Meter design

Status
Not open for further replies.

dudeshan

New Member
How to build energymeter(household) for energy/units measurements?
What is basic design idea?
Can we build it using microcontroller?
 
erm what about a polarised capacitor and a counting unit that counts every time the capasitor goes?
 
Energy is measured in watt-hours. Watts = voltage X current. Since the voltage is known and constant, you only need to measure the current and time. A microprocessor would be a good way to go.
 
Here is what I made a last year.
PIC 16F876
2x16 LCD
MAX 232
TL084
and 2 old monitor flyback transformer.

Since the voltage is known and constant, you only need to measure the current and time.

I made a current transformer from the Flyback ferrite core.
This ferrite core goes around the main AC line in my fuse box.
It has 100 turn, for 1-100 ratio.
1 amp= 1mv, 102.4 amp= 102.4mv
In my hose there is 2 line come in, so many of the appliance and light feed from different line, I made 2 of this.
Then feed in to a full wave AC/DC convert made of 2 of the four OP-AMP in the 084.
Scale it up to 0-1.024V = 0 to 102.4Amp, my reference voltage is 1.024V to make the math easier.
Than use whatever language you more comfortable to make your code.
In my case BASIC !
I made the projection for current"1sec", 1hr, 1day, and from last reset.

The truth is, I was try to advance it so it will have 64k I2C memory and RS232 link to PC, on the end I have so many time removed from the fuse box on the last attempt the ferrite core bracket touched the unfused terminal of the main line.
As the result I seen a fire work in my basement, and I promised my wife I'll never touch it again !!

Good luck
I hope is helped !
STEVE
 

Attachments

  • currentt_442.jpg
    currentt_442.jpg
    12 KB · Views: 904
Good job making your own CTs. They can be expensive, for a roll of wire around a bunch of iron.

In your picture, one of the cores is split. Do they come that way, or did you cut it yourself? I'd prefer a split-core so you don't have to break the connection (or turn off the power :oops: ) to put it on.

j.
 
It is from the flybak transformer of the Monitors.
I think in the last 50 years all made in two split pices !

For the power switch, I installed the curent trnasfomers in the main line, before the fuse brakers, there is no option to turn it off.

STEVE
 

Attachments

  • flyback_178.jpg
    flyback_178.jpg
    9.4 KB · Views: 826
One of these Ferrite toroids scavenged from some old equipment will work fine for making a current transformer.

Ante :roll:
 

Attachments

  • toroid.jpg
    toroid.jpg
    44.3 KB · Views: 982
Readymade dedicated Energymeter ICs

Hello,
Analog Devices Special Energymeter IC 775X series.
Good sophisticated ICs , whats more, they give free samples also.
It has serial port facility so that we can calibrate it externally, have interface with microcontroller.
I am making this project "Prepaid Energymeter".

Please review datasheets of these ICs, they r lil complex but good1s.
What do u think abt this ICs, do reply back.

**broken link removed**

dudeshan.
 
Russlk: i don't think you can make the assumption that the voltage is constant. I think you can only expect +-10%. My work is on the end of a long circuit and our voltage is all over the place.

Cypress has a reference design using their programmable analog microcontroller as an energy meter.
 
bmcculla said:
Russlk: i don't think you can make the assumption that the voltage is constant. I think you can only expect +-10%. My work is on the end of a long circuit and our voltage is all over the place.

I built a project out of EPE a good few years ago, it used a hall effect transformer to monitor the current. It also measured the voltage as well as the current for each sample, and did the maths, as you say you can't assume the voltage is constant!.
 
The meters that are normally used in residential applications where I live have a rotating element that has a light background with several black markings on the periphery of the element. It would seem that an optical means of counting the rotations could provide the information you need. The meter is owned by the utility so the sensor would have to look thru the glass enclosure. While this might be a bit of a challenge it certainly presents less of an electrocution risk and should correlate well with utility bills.
 
stevez said:
The meters that are normally used in residential applications where I live have a rotating element that has a light background with several black markings on the periphery of the element. It would seem that an optical means of counting the rotations could provide the information you need. The meter is owned by the utility so the sensor would have to look thru the glass enclosure. While this might be a bit of a challenge it certainly presents less of an electrocution risk and should correlate well with utility bills.


Is this not self-defeating? All you are doing is measuring the same quantity twice. Why bother? Just read the utility meter.
 
The common utility wattmeter (in this area) provides only a totalization of power consumption. By counting the revolutions of the wattmeter and storing it you can create a real time picture of your total power consumption. This data may be of significance, depending on what you are trying to do. I suppose that you could take hourly or daily readings but that's a lot of work - and you still have to enter the data if you want to analyze it.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top