Wireless high frequency data transmission from multiple sources

Projects Networking, Protocols, and Devices
1

Hi everybody,

I am new to the Arduino world and I should realize such a structured project:

  • three Arduinos, each connected to a sensor and a wireless transmission module (wireless sensor nodes);
  • a base node that receives data in real time from all three sensor nodes simultaneously (for now I should use a PC and maybe in the future a Raspberry Pi).

Considering that all the three sensors must provide data at the same time with high frequency (every 0.01 s), and must be synchronized, so that each sent value by the three sensors is recognized by the base as belonging to a specific time instant, I would like to ask what solutions do you recommend for wireless transmission. Is it possible to equip the receiving base with only one wireless module and receive three different signals at the same time? I specify that the distances are quite small, about 10 meters.

I did a research and found two possible solutions (correct me if I'm wrong): ESP8266, which seems more powerful and is capable of simultaneously transferring input and output data, and the NRF24L01+, which is cheaper and consumes less power, but I can't understand if it is possible to use it for my own purposes.

Thank you a lot in advance.

2

Would it be practical to collect (say) 8 readings each with a timestamp and send the data in blocks of 8 at longer intervals?

Even if you send the readings one at a time I think you should send a timestamp with each to guard against the risk that some items of data get lost in transmission.

The advantage of an ESP8266 is that it uses WiFi and can communicate directly with a PC.

The disadvantage of an ESP8266 is that it uses WiFi and requires a knowledge of web programming both for the ESP8266 and for receiving the data on the PC. If you are already familiar with web programming that should not be a problem.

If you are not familiar with web programming then I reckon you will find nRF24L01+ modules easier to use. Have a look at this Simple nRF24L01+ Tutorial. For the requirement you describe I would choose the style of the 2nd example where the master regularly calls to the slaves to collect their data.

...R

3

Thanks for the quick and precise reply! Sending longer intervals would not be a problem: I had not thought about the possibility of losing data!

I think I will study the recommended post and try to use the nRF24L01+ technology if it is simpler.

What about XBee (802.15.4)? From a little research it seems that it is very expensive, but ensures more reliability and less power consumption.

S

4

I have no experience with XBees because of their cost. I doubt if they would be any more reliable than an nRF24 which has extensive in-built error checking.

My suggestion is to try the nRF24s as the trial will not cost too much if it proves unsuitable. However I expect they will be fine.

...R