Hello,

I have an application where values are requested by a host to one or more clients. The clients consist of specific, non-related modules, usually connected to one or more sensors obtaining some sort of data.

I have created a simple messaging protocol where the host polls each client. The request triggers the generation of a custom, up to date response on the client (in accordance with the message received) and sent back to the host.

Due to these requirements, I started by testing the ManualAcknowledgements.ino official sample, which seems to meet my needs.
I took the sample AS IS, without any modifications (other than debug-mode activation and PA_LEVEL, which doesn’t seem to change anything).

For my tests I am using two official Arduino UNOs, even if I have something else in mind for my final host system.

As for the radios, I use two ITEAD nRF24L01 radios, the small ones, with the on-board antenna. I started by using Amazon radios, where I originally had this same problem, but I imported these from ITEAD since I read some threads talking about acknowledgment issues due to bad quality clone chips.

The nRF24 library version is 1.4.8, available directly on the Arduino IDE library manager.

The radios are also physically extremely close, maybe 5/10 centimeters apart.

I am having an issue with this particular example where messages are sent by the TX board (role 1) and apparently received by the RX board (role 0), but the acknowledgments do not seem to be working properly.

On the TX side, I systematically receive a message:

Transmission failed or timed out

This means that the write() function is always returning FALSE for some reason.

On the RX side, which interestingly prints a message for every message sent on the Serial Monitor, always prints the message:

Received 8 bytes on pipe 1: Hello 0 Response failed.

If I activate de debug mode (pretty print), I have the following information on the TX board at the start of the program:

SPI Frequency = 10 Mhz
Channel = 76 (~ 2476 MHz)
Model = nRF24L01+
RF Data Rate = 1 MBPS
RF Power Amplifier = PA_MAX
RF Low Noise Amplifier = Enabled
CRC Length = 16 bits
Address Length = 5 bytes
Static Payload Length = 8 bytes
Auto Retry Delay = 1500 microseconds
Auto Retry Attempts = 15 maximum
Packets lost on
current channel = 0
Retry attempts made for
last transmission = 15
Multicast = Disabled
Custom ACK Payload = Disabled
Dynamic Payloads = Disabled
Auto Acknowledgment = Enabled
Primary Mode = RX
TX address = 0x65646f4e32
pipe 0 (closed) bound = 0x65646f4e32
pipe 1 ( open ) bound = 0x65646f4e31
pipe 2 (closed) bound = 0xc3
pipe 3 (closed) bound = 0xc4
pipe 4 (closed) bound = 0xc5
pipe 5 (closed) bound = 0xc6

And on the RX board, I have the following information at the start of the program:

SPI Frequency = 10 Mhz
Channel = 76 (~ 2476 MHz)
Model = nRF24L01+
RF Data Rate = 1 MBPS
RF Power Amplifier = PA_MAX
RF Low Noise Amplifier = Enabled
CRC Length = 16 bits
Address Length = 5 bytes
Static Payload Length = 8 bytes
Auto Retry Delay = 1500 microseconds
Auto Retry Attempts = 15 maximum
Packets lost on
current channel = 0
Retry attempts made for
last transmission = 15
Multicast = Disabled
Custom ACK Payload = Disabled
Dynamic Payloads = Disabled
Auto Acknowledgment = Enabled
Primary Mode = RX
TX address = 0x65646f4e31
pipe 0 (closed) bound = 0x65646f4e31
pipe 1 ( open ) bound = 0x65646f4e32
pipe 2 (closed) bound = 0xc3
pipe 3 (closed) bound = 0xc4
pipe 4 (closed) bound = 0xc5
pipe 5 (closed) bound = 0xc6

I also tried using other radios, including some bought from ITEAD, since I read some threads about acknowledgment problems due to bad quality clone chips (my first ones, where the problem is also present, were bought from Amazon)

Can someone please test the ManualAcknowledgements.ino sample and share the test results?

Thank you very much

PFPP