Suggestion on how to acquire wireless CAN messages

[FedeSAE]

Hi,

I am working on a data acquisition system for a Formula SAE car.

We currently have a system in place but I would like to see what to do for the future.

I would like to use wireless transmission with a rate of 1Mbps using a PDA and a CAN2 PCMCIA or E series PCMCIA card.

Our PDA is wireless enabled and I would like to know if there are any other pieces of hardware that we may need in order to acquire the data with the PDA and simultaneously send it over a laptop using a Wi Fi connection.

I am at the beginning stages of this idea since we just finished a wired configuration.

Thanks for your help.

Fede

[Robert M]

Hi Fede,

As far as the PCMCIA cards are concerned, how the data is transferred from the PDA is transparent.  If you have the same configuration working wired up, then the only difference with the wireless connection is going to be the data rate and reliability.  If the wireless connection can handle the amount of data you need to send then the only suggestion I would have is to make your code robust enough to handle losing the wireless connection for a few seconds.  No additional hardware should be required.

Hope this helps,

[FedeSAE]

The thing that I am wondering is if I need a VI that will send out data via COM port.

Also, does Labview sees a wireless connection as a COM port?

In order to make this work I need a vi that sends data (PDA) and a vi that saves it (PC).

Am I correct?

Do I need an add on to develop VI to work with wireless setup?

Thanks

[ChrisJ]

Hi Fede,

Yes you would need a VI running on both the PDA and the host computer (one to send the data and one to receive it). If they are on the same network, then you should be able to communicate between the two using the network protocol of your choice (tcp or udp). There is an sender/receiver example for both TCP and UDP in the LabVIEW 8 example finder. Keep in mind that with UDP there is no error checking, so data can be lost.

Best of luck!
Chris J

[FedeSAE]

I checked those examples but what I am not clear about is on how to select the communication port.

in the TCP listen VI how do you tell labview to check the wireless card for the check for network addrress?

The TCP open connection VI opens the communication. How does it know on which device?

I am new to this and I do not want you guys to do it for me. I am just looking for some things that I can read and the examples are not helping me much.

Thanks

[ChrisJ]

Hi Fede,

The TCP Listen and Open connection VIs have a port input where you can specify the port to use. Outside of that everything is handled by the operating system.

Cheers,
Chris J

[FedeSAE]

I am sorry If I sound stupid, but how do you exactly choose a wireless card or ethernet port?

Thanks for your help

[FedeSAE]

So,

from what I have read you insert your TCP/IP or the PC name and let the software work automaticaly and you decide which port to use as long as open and not closed by the firewall.

So labview will use the first available mean of sending data and that will be aither ethernet cable or wireless card.

Also, I have to set the PDA as a server and the PC that reads that data the client.

Is it possible to read the data while the PDA is reading it or I have to wait until the file is closed?

Thanks guys.

[Andy F.]

Hey FedeSAE,

You are correct, the software should handle all of the communication (wireless, ethernet) for you.  So are you trying to write to a file on the PDA and send data using TCP/IP?  Technically, you shouldn't have a problem doing both in a loop since the two protocols really don't have anything to do with one another, but in reality the limited processing power of the PDA may hinder this type of application.  If you are sending the data to a PC you might consider writing to file there if you do indeed need to write a file. 

Hope this helps!
Andy F.

[FedeSAE]

What I would like to do is read the data that the PDA is reading in the client PC and save that data simulataneously.

I have a VI that reads and saves on the PDA and the next of the project is going to try to get that data sent over TCP/IP from the PDA to the PC.

I am trying to create a live telemetry for a race car.

I could probably use the current VI that saves and add to it few lines that will allow the PDA to send the data with WiFI technology.

I was trying to use data sockets but Labview PDA doesn't support them so I will try to see I can use the active and passive TCP/IP VIs.

Also, is there a way to specify the TCP/IP address of the PDA with labview since I cannot find the IP address of the pocket pc.

Thanks