Collecting data wireless from 200 arduino

Hi all
I am making a project using arduino
My object is to collect data from many machine (nearly 100) and show that data on pc..
Method I used :-
I used mysql to get data from arduino using MYSQL COLLECTOR library and made a .Net application to use that data .

By now :-

  1. I have tested my code on one arduino and Ethernet shield.
  2. Made .Net application

Stuck at
How to send data from all arduino to PC wireless... :confused: :confused:

I though:-

  1. nrf24l01 - - - using nrf24l01 mesh I send data one by one to master station and then this master station upload the data to MYSQL for each machine.... (is it relay able)

  2. I use WiFi shield at each arduino and directly connect to MSQL server (can router handle that many connection)

Please suggest me and tell me if any other option is available

I will appreciate help as I really need to do this...
Thanks in advance

What range do you need? How muich data do you need to send?
How fast do you need it?

regards

Allan.

You can use very cheap radios (like the 433 MHz TX/RX modules) as long as you don't need to send much data very often.

If each module sends an ID byte and a few bytes of data in, say 50 milliseconds every minute with nonoverlapping transmissions, that would be 1200 time slots per minute for a single frequency channel.

In practice transmissions will overlap, but that can be solved if a module makes repeated transmissions with random delays between transitions.

How far apart are your Arduinos.?

How many bytes do you need to collect from each slave every minute?

If the range is suitable think using the nRF24s as in the second example in this Simple nRF24L01+ Tutorial should work. The idea would be for the master to question each of the slaves in turn. That way there would be no confusion about who was sending the data and it would avoid the overhead of the Network or Mesh systems.

If you need longer range then the Network may solve the problem - or perhaps you could have some "sub-masters" as concentrators to collect data from outlying slaves and pass it back to the main "master". But even that adds overhead to the system.

...R

WiFi appeals to me, because the diverse network protocols are already defined.
To go for Zigbee, or other mesh/flat low-cost network means an investment in time for low-level development and implementation.