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How can I to discover the access points in my cover range wiht LabVIEW

I'm working in a investigation proyect about LabVIEW PDA module, the proyect consist in the control of the wireless ports of PDA using LabVIEW. Until for days I'm working in the part of Bluetooth but from the last week I'm working with the wifi port in PDA. The problem I have is know if is posible to make a list of the differents access points inside the range of cover for after conect to any one. The TCP/IP open conection function need that i introduced a specific adress in this field, but i need know if is posible how in the bluetooth functions make a list with the diferents acces point, for after select any one to conect.

Thanks for your help.
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Message 1 of 7
Unlike bluetooth, WiFi stations are invisible to LV - it treats them just as it would a regular LAN. The device itself decides which access point to connect to.
You will only be able to control this if you can write code in a different language which will interface with your device and tell it to connect to a specific AP. If you can write such code, you can also call it from LV.
Otherwise, you will have to your device yourself which network and AP you want to connect to.

Try to take over the world!
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Message 2 of 7
OK!! Then there is no function seemed to de discober function in bluetooth functions.

After your answer i have Anothers questions:

1.- what language can i use in order to develop this aplication,

2.- can i develop to start off a source code found in internet,

3.- How i can call this code to execute in my aplication VI.

Thanks, and sorry by the annoyances.
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Message 3 of 7
If this is at all possible, you should be able to use Basic or C to create a DLL, but since you're asking, I presume you don't have enough knowledge in those (at least with regards to PDAs) to do this.

You can probably find some documentation on the internet, but I wouldn't know where, and I have no idea how to do this myself.

If you get the code, you can call it by using a Call Library Function Node. This is documented in the PDA module's user manual.

It's not annoying.

BTW, why do you need to select an AP?
Unlike BT, WiFi doesn't connect you to a single device but to a network. If there is only one AP, the PDA will connect to it.
You will only need this if you have more than one AP in your area, and if it's connected to a different network.
I agree that it would be better if the user didn't have to select a network, but at least there are less APs around than BT devices (in most places, anyway).

Try to take over the world!
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Message 4 of 7
Thanks for your help!!!

I have spoken with my project director to comunicate what happens, now i must make a sweeping but in a LAN and make a list with the adress of the devices that has conected.

I have a router wifi, it holds 250 devices. I have thought make a vi with a for loop to try to conect with a devices in order to iteration terminal count(2-250), if it has been able to connect to the device, the status terminal of the error out of close conecton function make true, keeping the direction in the list.

I enclose to you a portion of VI.

I hope not to have been a heavy one.

Thank you very much.
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Message 5 of 7
Some comments about your VI:

1. I'm not sure whether placing a dot after the IP address will work. I know it isn't necessary.
2. If you want to run up to 250, change the 254 to 249.
3. If you open a connection to 250 devices, it will take a while. If you don't, the 500 ms timeout for each one will cause this to take more than 2 minutes for all the devices.
4. Since you're also doing 30 ports for each device, this will take an hour. You can minimize this by using a while loop and stopping when you managed to open a connection or by knowing the port in advance.
5. The devices can't react to a TCP Open if they don't have the proper programming (they have to be listening).
6. You may consider using UDP instead. It can broadcast a general call instead of calling each device personally. It should bring your detection time down to a few seconds. You will have to do some reading about UDP first.
7. The status output is T when there is an error.

If you want to learn more about LV, I suggest you read the LabVIEW user manual. Also, try searching this site and google for LabVIEW tutorials. Here and here are a couple you can start with. You can also contact your local NI office and join one of their courses.
In addition, I suggest you read the LabVIEW style guide.

Message Edited by tst on 05-19-2005 07:03 PM

Try to take over the world!
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Message 6 of 7
Excuse me, the VI i enclose is a sketch, I have done it to make you an idea of de vi I want to do, not is a definitive vi.

Of everything what you have said I remain with the functions UDP, because the other questions I have already said to you that it was a sketch (one assumes that there is some listening in some device).

I'm working with labVIEW a few moths and in TCP/IP conection only a few days, but already now this exercises and I read the users manual but of all ways is good for having information of courses and tutorials since it is never known everything of LabVIEW.

Excuse me, and thanks for yor time.

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Message 7 of 7