Wireless Communication

Wireless & IoT
1

I am wanting to record GPS data to temp flash and then send the data to a computer when the GPS unit comes in range.

Basicily I am wanting to collect data as a bike goes around a track,

Low power devices would be optimal so the battery doesn’t weigh the bike down too much.

I have a ATMEL Processor to interface the GPS and the Communication.

Question

What WIFI communication would be best?

Also is there any preference for the GPS unit?

I have limit experience in these areas, so any knowledge is a bonus.

Cheers

Hovo

2

Range?

Leon

3

50-100m would be good.

So nothing high powered is needed.

Most of the power could be in the receiver with the pc.

4

The nRF24L01+ modules SFE sells could be suitable. They have very low power requirements.

Leon

5

Hovo:
I am wanting to record GPS data to temp flash and then send the data to a computer when the GPS unit comes in range.

Basicily I am wanting to collect data as a bike goes around a track,

Low power devices would be optimal so the battery doesn’t weigh the bike down too much.

I have a ATMEL Processor to interface the GPS and the Communication.

Question

What WIFI communication would be best?

Also is there any preference for the GPS unit?

I have limit experience in these areas, so any knowledge is a bonus.

Cheers

Hovo

Consider IEEE 802.15.4 (such as Digi/Maxstream XBee) versus WiFi 802.11. For the latter, consider ConnectOne’s product. But use WiFi only if you need broadband speeds, or if the client device should easily connect to an existing WiFi network. Two different wireless approaches.

There are many proprietary wireless radios too, like the Nordic mentioned. These are sole-source, but lots of people here use them.

6

Thanks for your input,

I don’t mind having a different box (WIFI card) sitting on the side of the computer to pick-up whatever frequency I use.

The main problem I foresee is having multiple transmitters coming in and out of range of the receiver.

I know there will have to be some sort of transmitter identification and some acknowledgements to reduce the loss of data.

So how do these Wireless transmitters work?

Do I have to connect to a network like in a Wireless Computer Network?

Or do they broadcast on a frequency and don’t care if the message is received by anyone?

This then prompts me for data security,

is there any hardware encryption?

Cheers

7

With an 802.15.4 module like Xbee, Jennic or many others, it’s a simple “modem” to you. You talk to it with serial port data (either as RS232 from a PC’s serial port (or via USB) or as logic level from a microprocessor.

Using factory firmware in the module, the serial data is recreated across the wireless link, and appears again on the other end, much like a pair of old modems. This is wireless transparent serial port extension. The Xbee’s sold here do that (series 1 is best for this). So you get a pair and write no code.

And vice-versa for return data.

You can do addressing, to send data to a selected module based on its address, talk to it bi-directionally. Then change the address. Or do a Broadcast To All.

The 802.15.4 modules are like $20. To do this with WiFi is much more expensive, and impractical for battery powered devices. But the ConnectOne module (not sold here, but see their web site or Mouser.com), really makes it simple, if WiFi makes sense.

802.15.4 and WiFi have encryption. 802.15.4 uses AES128. Or you can encrypt your application data yourself.

Broadcast-to-all data frames are not done with acknowledgments and error correction. Point to point frames are (option in 802.15.4) acknowledged and retransmitted if need be.

Study up!

8

Thanks for pointing me in the right direction…

Now for manual reading…

Cheers

Hovo