Arduino with NRF24L01. Getting correct data from unkown transmitter

Question

I want to use my Arduino with this: VAC8010F measure unit. It communicates with NRF24L01. The problem is I simply don't know which band or information it is receiving. Can somebody help me with this?

Thanks for any suggestions!

• the busybee: What does your favorite search engine reveal? What did the data sheets and documentation tell you? What is it what you do not understand in their contents? -- Please take the tour and read "How to Ask". Then show some effort and come back to edit your question.
• Gerben: You need to know the channel and the pipe-id (and speed, though my guess would be 1Mbps). To find the channel github.com/nRF24/RF24/blob/master/examples/scanner/scanner.ino might help. Not sure how to find the pipe-id.
• Avamander: One possibility is sniffing the SPI bus and seeing how the module is configured. Another is using an SDR and decoding the communication on-air. Third method is dumping the unit's firmware and reverse-engineering it. Any other methods are probably too slow, I'm not aware of a promiscuous mode on the nRF24L01+ and checking all speeds, channels and pipes is way too slow.
• Avamander: Sniffing the SPI bus is probably the easiest, you could possibly even attach your own wires to the bus and possibly read out all the registers.

Answer 1

Don't have full details yet. But the VAC8010F uses modbus RS485 protocol. My research shows that the NRF24 just transmitts and receives the MODBUS protocol to and from master/slave. I have found modbus libs and samples of code on the net. There is a command driven program to communicate with MODBUS free for linux, which is the o/s I use. I don't know about win. Anyway, once I receive the MAX485TTL interface for my ARDUINO MEGA I will write code for data logging to p.c. then modify to use the NRF24, as I should be able to extract the ADDRESS, and CHANNELS etc, and packet construct.

Hope this is of some help.

Patrick

Answer 2

Nordic has an app to connect to nRF https://www.instructables.com/Send-Data-to-Mobile-Using-NRF24L01-Using-NRF-As-a-/

The app is available for all platforms. Did not try it myself. Hope this helps. I going to do the same, but want receive it on Android.

If you got some news, please let me know. Thanks

• Rudi: Have got a cheap Logic Analyzer to use with Saleae Software. Many protocols can be choosen including modbus. @Patrick: Do you know the baudrate? is it RTU/ASCII? Who is Master/Slave?