Hello. I work with caravans and everyday we must read how many watts different things sutch as waterheater, immersion heater, floorheater etc. And they got different levles to check. We only have a wattmeter in the wallsocket outlet, so you can imagen all the runs back and forth in and out of the caravans to check so they all work correctly. Im sure i woudl make me and my colleagues very happy if i could make this watt reader wireless. Any ideas as to how this can done? Im still novise so not to complex pls. The exact reading and values are not important. We just need to check if the different 230v systems in the caravans works roughly around the levels they are suppose to. Also its mainly the part of 230v watt reading functions im intressted in, not the cordless data transmission part. I was thinking of using a ACS712, but there are no tutorials out there that shows this using 230v 
I don't understand the application. Is this intended to be a permanent installation in the caravan? Is it intended to measure the individual loads simultaneously or are you switching them on one at a time and looking at the meter? You are building the vans and just need to check that all the wires are connected under the floor?
If it's the latter, I would get two long extension leads and a plug-in type wattmeter. Put it between the leads so you can carry it inside the van while the output lead goes out the door and into the inlet socket of the van.
The number of watts each appliance consumes is usually printed on its label - I can't see why it is necessary to measure it again.
If the purpose of the exercise is to see if the electrical circuits work it seems a rather unusual solution. Why not just use a phase tester or an electric lamp ?
...R
I think the OP works in manufacturing caravans and needs a way to verify each appliance is operating as they are wired in.
May I suggest a clamp-on digital multimeter for each worker? We have a company caller "Harbor Freight" in the USA and they show a useable VOM for $16.00 american dollars. You probably have access to similar devices. These would be quicker and cheaper than than a wireless wattmeter display. Also would allow more than one device to be activated at a time. your wireless plan would be chaos with more than one person wiring up the appliances.
Paul
At my work we sell caravans and motor homes. And i work at the workshop. So whenever a caravan is sold we need to check all functions are working properly before the customer picks it up. For there and our sake. Guarante, insurance etc..
From the caravan you connect an 230v cable to the main outlet. It feeds the varous 230v functions in the caravan sutch as heaters etc.. Now i was thinking to have my reader plugged betwen main outlet and 230v cable going into teh caravan. So that mine device can be used at other main outlets if we want to. Pritty mutch like this one here...
We are using this kind now , but we need to run back and forht every time to check differnet wattlevels of different things in teh caravans. So i want to make my own that can send the watt value to a cordless display while workign inside the caravan
Thank you for the update. Makes a lot of sense. Are you interested in producing a commercial product? I don't see any reason for an Arduino in the system. Perhaps others can see it working with the salesman's smart phone!
Paul
commercial product.. hmm no not realy. Im intressted in making mine and my colleagues life at work a lot easier.
mansilla:
At my work we sell caravans and motor homes. And i work at the workshop. So whenever a caravan is sold we need to check all functions are working properly before the customer picks it up. For there and our sake. Guarante, insurance etc..
I still don't see any need to measure watts.
If you want to prove that (say) a microwave oven works then try it out on your work bench before it goes into the caravan - or just use a reputable supplier.
If you want to prove that the socket in the caravan can power the microwave then test it like any qualified electrician would do - with proper electrical test equipment. Then you might have some useful evidence to put before your insurers or the courts.
...R
Ok ill try explaning it again...
Some functions has differnt levels , like heaters have 3-4 watt levels, dependeing on how hot you want it. And sometimes these things just dont work, couse they are old,(we do sell old caravans to, trade.ins) and this is a fast way to se if they work. You see,, we dont realy wanna be in teh caravan to see if the caravan get hos to 1kw after 10 min then bring it up to 2kw and wait more and sit in there and wait with a thermometer. Same with floor heater and ather stuff.. jesus crist.. ofcorse we would just turn on a microwave to test that.. but oh nevermind.. its more complex then that. Anyway we a required to do this so, lets just talk about the topic please
just cause robin doesnt understand isnt the end of the world, arduino yun connects to the internet smartphone eaiser
seems like people are questioning 'why'
the OP is asking 'how'
http://openenergymonitor.org/emon/node/58
the wireless is not hard if the distance is within 50 meters.
I thought you were making new caravans. I did not realize you were doing some quality control on used caravans. If I missed where you said that, I apologize.
A simple solution might be a wireless web-cam watching the meter and displaying the picture on a small laptop inside the caravan. No need to tamper with high voltages.
Or, if you can read the watts with an Arduino attached to your meter could you transmit the data with bluetooth and use the RemoteXY program on an Android phone to display the data.
Or, use a Yun to serve web pages that can be viewed on any WiFi device with a browser.
...R
mansilla wrote:
Im still novise so not to complex pls.
From reading this thread, and making a few assumptions, namely that the OP presently would seem not to have the necessary skills to undertake what would seem to be a more complex project than a novice could undertake, I support those who say that you really should be looking to either, buying a ready made product or hire someone who can and does fully understand all parts of what your needs are.
There is one component about your project that suggests to me a need for a high level of safety, as you are dealing with mains potential of 230VAC. Mixing this with small boards like Arduino, needs attention to maintaining the required level of safety.
Since this is being used in a business where other people may use this device you have in mind, you will also need to think carefully about your liability in terms of what happens if other of the other staff members of the business unfortunately gets electrocuted and suffers or dies from your device, where do you stand in terms of the law?
You go on to say:
The exact reading and values are not important. We just need to check if the different 230v systems in the caravans works roughly around the levels they are suppose to. Also its mainly the part of 230v watt reading functions im intressted in, not the cordless data transmission part.
I am trying to untangle and make sense of your words, but, again I can only make a guess, and that is you want some form of data logger that will read and record the power levels in Watts of the mains connected appliances in the caravan as you switch them from off to on or from off to different power levels.
And that you wish this to be more automated than the method you are currently doing, is this correct?
I was thinking of using a ACS712, but there are no tutorials out there that shows this using 230v
There is an abundance of online information on these devices, but being a current device, they are therefore by definition, independent from the voltage on the line you are measuring, within the specifications of the device.
Be aware that if you are measuring an AC signal, you will need to process the signal in either hardware or software to derive the RMS of the sinusoidal signal.
What you need to do is to think about and write down a list that clearly defines what your needs are.
For example, will you only measure power in Watts?
If so, you need to know the volts and the current and power factor of each device to be able to calculate power in Watts.
What is the range of the Watts you wish to measure, and to what accuracy ?
Do you need to know power consumption, as in Watt Hours ?
Do you need to be able to produce a document or report as proof of evidence, for your own records or for others ?
There will be other things on this list I am sure.
My honest opinion is that for you to design and develop and put into operation a system that will fulfil your needs and remain safe may well be more complex than you capable of undertaking at this stage.
Note: Please keep in check your usage of emotive language as in your post #8, people here tend not to tolerate it very well and and any help offered may well diminish fast. I'm sure Robin recalls a recent thread where we had this happen.
Paul