Wireless Energy Monitor Circuit in Elektuur

Post by **Bwired** » Mon Aug 20, 2007 11:20 pm

In the Elektuur (Dutch Electronics magazine) of September 2007 there is an article about Wireless Energy Monitoring. It's a project to build a wireless monitoring system for complete energy consumption including the needed software. I haven't seen the complete article yet but when I do I will update this topic with extra information.

Nice thing is that Bwired.nl is also mentioned in the article [:)]

Update: I thought allready it had a touch of Heino Peters, DMB told me it is designed by his son Jeroen Peters (cool!)

http://www.elektuur.nl/artikelen-als-pd ... ynkx?tab=2

Pieter Knuvers
www.bwired.nl Online House in the netherlands. Domotica, Home Automation.

Post by **Bwired** » Tue Aug 21, 2007 12:10 pm

Our German friends from Elektor are also running the article!
http://www.elektor.de/jahrgang/2007/sep ... ynkx?tab=2

Post by **Snelvuur** » Tue Aug 21, 2007 12:29 pm

and www.bwired.nl is there with a link too..

// Erik (binkey.nl)

Post by **RDNZL** » Sun Aug 26, 2007 3:10 pm

Did anybody build it yet?

I build the receiver first, but I do not get any text on the display yet.

Replaced the Pic, xtal and lcd but they don't seem te be the problem.

I can program and verify the pic in circuit, so power and main pic connections are ok.

Hmmm

Post by **RDNZL** » Sun Aug 26, 2007 4:46 pm

Fixed!

TIP: Never connect an LCD display to a PIC around 0:30 o clock

Those LCD's have odd pinouts...

14 - 1 16 15

I was counting 14 -1 only and forgot about the backlichting pins, so most of the connections were 2 off. [:o)]
But luckily nothing was damaged...

Post by **DMB** » Sun Aug 26, 2007 10:09 pm

Ron,

You did it.
Jeroen can be proud.

DMB

Post by **RDNZL** » Mon Aug 27, 2007 1:24 pm

ERRATA:
In the transmitter I had to replace the 1Kohm resistor which feeds the led in the CNY70 with an 68 Ohm one.

Otherwise the sensor doesn't work properly because the current flowing through the led isn't enough.

The CNY70 led needs 1.6V 50mA according to the datasheet.

Post by **Heino Peters** » Mon Aug 27, 2007 7:26 pm

RDNZL,

According to the specifications you're right, but the resistor will become rather warm. I would advice a 100 or 220 ohms one. I tried it with 1k and it works ok, but do whatever you think is best.

This article has not only been published in Dutch and German, but in Englisch, French and I believe Greek as well! Well done, Jeroen, but I know we aint seen nothing yet... This is only the beginning.

Heino

Post by **RDNZL** » Mon Aug 27, 2007 8:45 pm

Heino,

I couldn't get any result with a 1k resistor. Maybe the manufacturer of my CNY70 is different. Mine are from Vishay. But you are right 68 Ohm is a bit to small perhaps. Point is, I have a energy meter without leds, so I have to adapt the gasmeter sensor schematic to read my energy meter, and tarif as well. From another project I have some OPB704 opto's laying around, they were quite expensive, but will become handy perhaps. When do you adapt the firmware in Jeroen's transmitter to talk to your rf interface... haha

Post by **Jeroen Peters** » Fri Aug 31, 2007 9:58 pm

Thanks for your reactions. I noticed that the RS232 has been lost in the receiver. In the attachement you can find the right scheme.
If there are any questions, use this forum. Good luck!

Jeroen Peters

Post by **RDNZL** » Sat Sep 01, 2007 10:39 am

Hmm a little problem.

I have changed the CNY70 for an OPB704, and switched opamp inputs. (+ and -)

So the opto detects the black stripe on my energymeter with rotating disc, instead of a led blinking.

This works ok, only it generates more that one count/pulse. It keeps counting until the band has past the reader, how can I easily change the source code, or electronics so that it will only generate one pulse/or increase the counter once when the black band is passing the opto?
It's about 1 cm wide, but it stays a short or long time in front of the reader depending on how much current i'm using.

Post by **Heino Peters** » Wed Sep 05, 2007 2:44 pm

Ron,

I'ld suggest to use a (big) capacitor between the signal line and ground (or powerline, depending on your electronics) to solve this challenge. It reduces the effects of disturbances on the turning wheel.

Heino

Post by **timetec** » Tue Sep 18, 2007 6:29 pm

Hello everyone

Yippee !! - I have found a forum that is discussing this excellent project. I need some help,
but have help to give, so perhaps we can each build, really good systems together [:)]

The UK Elektor forum (I'm in England), is not very busy at the moment as they have just
redesigned the website and things seem very slow...

@ RDNZL

I also have a meter with a rotating disc with black stripe on the edge. I made up a simple comparator/trigger circuit to send 100m/s pulses no matter how slowly the disc is spinning.
It uses a LM393N 8-pin IC - I'll post the circuit on here very soon !
The optocoupler I'm using is an even small version of the CNY70 and has 2 tiny lenses on it.

Yes, the 1K resistor for the LED is way too high (only 0.5ma) at 5 volts.
Using a 220R now - 22ma and much more reliable [^]

My main problem is the coding for the meter 'speed'
The meter has really slow rate of 166.666 revolutions per kWh.

Has anyone got a meter running at a similar speed [?]

Richard

Post by **Heino Peters** » Tue Sep 18, 2007 8:56 pm

Richard,

I think you live in a country where sizes still are being measured inches, feet and miles and where euro's are not accepted...

The solution is easy. Change the software in the PIC for the transmitter so that it adds 6 units for every cycle. Your transmitter than behaves as if it gives 1000 imp/kWh. This will solve your problem. Don't forget to change the values in the receiver to this new number of imp/kWh.

Many succes, Heino Peters

Post by **timetec** » Tue Sep 18, 2007 10:50 pm

Hello Heino

Thank you very much for replying to my question personally [:)]
I followed the example in the transmitter ASM file (WEM zender), and could not resolve the X_1 value to 128 and got 219 instead :

3600,000,000 / 600 = 6,000,000 then 6,000,000 / 65536 = 91 (X_3) - OK

6,000,000 - 5963685 (91 x 65535) / 256 = 141 (X_2) - OK

6,000,000 - 5963685 (65535 x 91) - 36096 (256 x X_2) = 219 - Incorrect

However, if 65535 was 65536 above, you would get 128.
My meter gives 166.6666 (2/3) impulses / rotations per kW/h
So, firstly :

3,600,000,000 / 166.6666 = 216,000,00 - My parameter

216,000,00 / 65536 = 329 (X_3)

216,000,00 - (329 x 65535) / 256 = 152 (X_2)

216,000,00 - (329 x 65536) - 38912 (256 x 152) = minus -256 (X_1) ???

I am sorry for the very long calculations, but you can now see why I have been struggling with this.
Also, I was not aware that you needed to change and code in the transmitter (WEM zender.asm) software - there are no instructions.
Again, very many thanks for your help

Richard