NRF24le1 max no. of IR nodes?

[Matthews]

Hi friends,

I am doing a project in NRF24le1 using RF communication with multiple nodes with a host using star topology.

Could you suggest a Protocol that supports connecting upto 100 nodes with a single host

[ovrebekk]

Hi

We don't really have any out of the box-protocols well suited for doing huge star networks, you would probably need to do something proprietary on top of the ESB protocol.

If you have a single host talking to multiple nodes then you can have the host interrogate one node at the time, and differentiate the nodes by using unique RF addresses.

If you use the ACK payload mechanism you can have the nodes prepare some data for the host in an ACK payload, and as soon as the host sends a packet to the node the ACK payload will be sent in return.

The simplest implementation would have the nodes in RX mode constantly, waiting for the host to send a packet, but this wouldn't be very power efficient. If you need a more efficient implementation you can have the host interrogate the nodes at a fixed interval, allowing the nodes to sleep in between packets.

Best regards
Torbjørn

[ovrebekk]

Hi Matthews

I assume you are referring to the number of pipes in the radio, which is limited to 6 in the nRF24L series and 8 in the nRF5x series, but this is not really a limitation on how many devices you can talk to.

It is possible to change the RF address registers in the host dynamically, allowing you to talk to a virtually unlimited number of devices as long as you reserve a unique time slot for each one.

If you want to assign different frequencies to different nodes this is definitely doable, you can change frequency in the radio as easily as changing the RF address. Any change in the RF configuration require you to go into standby mode, change the registers, and power the radio back up again, which can all be done in a couple of hundred microseconds.

Best regards