The RF24 Wireless Communication Stack: Communication, Consistency & Exploits

 The RF24 Wireless Communication Stack: Communication, Consistency & Exploits

 Using RF24Ethernet & RF24Gateway for an IoT Network

 RF24Ethernet & RF24Gateway are two complimentary software libraries for Arduino that allow users to quickly design, develop & implement IoT networks that utilize TCP/IP for general communication. They use the Arduino Ethernet client/server APIs, so anyone with minimal programming experience can construct and deploy an IoT network in short order.

 

Recently, we discovered a buffer overflow in RF24Network that affected nearly the entire communication stack on Arduino devices. This buffer overflow was "externally triggered", meaning that an external user or system would need to send a certain packet type to a device to trigger the buffer overflow. It doesn't occur under "normal" operation of the system.

 

 The interesting thing about this, is that my devices have been susceptible to this overflow for a long time, and there has been near-daily attempts to disrupt my network. It seems that somebody nearby has a LOT of time on their hands, and a penchant for causing problems. 

 

The good part of this is RF24Mesh, the part of the RF24 Comm Stack that keeps things working, almost no matter what. RF24Mesh is a wireless-mesh system for the comm stack that provides addressing, DHCP type protocols, and self-healing/management of the network. With RF24Mesh involved, the network typically remains stable, despite the constant attacks.

 

  The exploit in RF24Network has now been patched, so users are encouraged to update as soon as possible.

 

 As far as the rest of the stack goes, everything is coming together with support for nRF52 and nRF54 radios, which now work with the comm stack. I have a little bit of work remaining in this regard, but basic support for these radios has been incorporated throughout the stack in the latest releases.

 

A chart of ping response times for one node on the network using NodeRed

 

 There are a lot of different uses for this system, from monitoring, to managing and collecting data from sensors, to remotely controlling devices, etc. and it is very flexible and standardized. I've been using the NodeRed system with MQTT mainly for my devices. MQTT is a standard protocol for messaging and IoT systems, so it is well suited to this type of thing.

 

 For anyone interested in wireless IoT systems, I would highly recommend checking out RF24Ethernet/RF24Gateway. You can be up and running in minutes, with a closed system using just two Arduino devices & RF24Ethernet, or a fully fledged IoT setup, using a Raspberry Pi/Linux for a gateway and a number of Arduino nodes running RF24Ethernet.

nrf_to_nrf Arduino Library: Now supports nRF54l15 devices!

 nrf_to_nrf Arduino Library: Now supports nRF54l15 devices!

New possibilities with nrf54l15 support 

 With the recent addition of an Arduino Core supporting nRF54l15 devices, I decided it was time to attempt to get the nrf_to_nrf library working with these devices. It was confusing initially, but once I worked out the specific differences in registers, things came together pretty quickly.

The main difference between these radios and nRF24 radios is the payload sizes and speeds. The nRF24 is capable of only 32-byte payloads, while the nRF52840 and nRF54l15 devices support much larger payloads. The nRF54l15 is also capable of 4Mbps transfer speeds.

The nrf_to_nrf library is designed to work out of the box between all 3 device types, but users can call 

  radio.begin();

  radio.enableDynamicPayloads(254);

prior to calling network.begin(); or mesh.begin(); functions to configure large payload sizes if setting up communication between nRF52840 and/or nRF54l15 devices. nRF24 is not compatible with sizes > 32-bytes.

I'm still working on getting encryption working on the nRF54l15 devices, and it seems to be a little more complicated than it was on the nRF52840. This might take a while to address.

The rest of the libraries, RF24, RF24Network, RF24Mesh & RF24Ethernet are being updated to accommodate the newer radios. 

 

 

nRF24l01 radios: Long Term Stability Issues & Error Handling Enhancements

 nRF24l01 radios: Long Term Stability Issues & Error Handling Enhancements

 Creating robust, reliable networks

 We recently identified and addressed some long-term reliability issues affecting the RF24 radio library for nRF24l01 radios. The issues affect any users that make use of the write() or txStandBy() functions of the library. About a year ago, we found some issues with the radios returning "impossible" values, with one register indicating a payload is available, another saying there is not, and another saying the payload length is 0. This and similar issues appear to have affected the radio in transmitting mode as well, a fact we missed upon initial review of the previous issue. Now, a year later, we've addressed issues affecting transmission as well.

 

As of this writing, we are just completing testing and the changes have been pushed to the master branch of RF24. A new release should be available in a few days (version higher than 1.5.0) for the Arduino and PlatformIO platforms. For now, users can install from ZIP or clone the RF24 repo directly from the master branch.

This should be the final fix for stability in the RF24 platform, as we seem to have identified and implemented handling for all failure modes now.