Wireless sensor network with nRF24LE1 and nRF24L01+

Question

Does anyone use nRF24LE1 and nRF24L01+ to creat a small size wireless sensor network? Could you give me some advices?
Thanks a lot!

Asbjørn · Accepted Answer

The number of nodes could be anything, you could say that the 5 bytes of address would be the limit, but that’s a very big number. A more practical understanding of the maximum number of nodes would be to have a look at the throughput. The nRF24L01+ in your setup would be the point where everything is sent. For the sake of this example let’s say you are using auto-acknowledgment in your setup. And you have 10 bytes of data that’s being sent from each node. You use 2 Mbps on air data rate with 5 byte address and 2 byte CRC. So the package sent from each node would be ~20 bytes long. It would take 130 us to get the radio into receive mode and about 100 us to send this packet. Then 130 us to switch around from RX to TX and 100 us to send the ACK back. So one information exchange would take roughly 460 us. For simplicity, let’s round that up to 500 us, which means that you can communicate with one node every 500 us or 2000 nodes each second under ideal settings. 
 Depending on what latency you can accept, you could say that for example you only need to communicate with each node once every 2 second, hence you would in theory have time to service 4000 nodes with a latency of 2 second. 
 The number of nodes is determined by how many addresses or how many tags you can store or identify on the receive side. This can either be the 5 byte package addresses or you can have all the nodes share some address and use parts of the payload to actually identify which node is sending the received data.