Nano and Radiohead Library not working

Hello, I have a Mega, a Nano and a Uno. Using the Mega as the Server and the Uno as the Client the RadioHead datagram works fine on both.

If I use the Nano in place of the Uno, same code and turn power off to the Uno the Nano returns "SendToWait failed."

After watching a Julian Lett video (can't find it right now) some time back he showed there is a different boot-loader in the Nano to the Uno and he over-wrote the nano with the Uno loader and it then thought it was a Uno.

I do not want to have to over-write the bootloaders of the Nanos.

How can I get this working with the Nano and it's standard boot loader?

Thank you.

The different bootloader can not make a difference when running a sketch. They both have the ATmega328P at 16MHz.

Do you have a clone Nano ? which is actually a fake Pro Micro with a ATmega32U4 ?

Or do you have a real Nano, with the genuine FTDI chip ? That chip is used to make 3.3V, and not a lot current. If your transmitter needs 3.3V, then that might be the issue.

Thanks, both the Uno and Nano are clones, but I am running all nRF24 modules from breakout boards with a 5vdc supply as they have 3.3vdc regulators for the nRF24 so I doubt current is the issue.

The sketch used 9600 Baud for the Serial Monitor so I raised that to 57600 and got about 40% good throughput so then went up to 115200 and I am getting some success at about 85% of the times. Not perfect or reliable, but it is kind working compared to the Uno with 100% results. Might be something to do with the UART on the Nanos hogging CPU cycles?

I will try with another brand of Nano and Mini clone I have.

It is still the same ATmega328P microcontroller at 16MHz on both the Arduino Uno and Nano. There is absolutely no difference, the chip die is the same. It has not to do with cpu cycles.

The trouble could be the serial-usb chip and the electronic components around it. The serial-usb chip is between the usb connector and the ATmega328P. Or something is wrong with the voltage, or the decoupling of the voltage. Perhaps you need a better USB cable or another USB port.

For the Uno, the serial-usb chip is the ATmega16U2 on the official board, or a CH340G on the cheapest clone board. For the Nano, that is the genuine FTDI chip on the official board, or a CH340G or a counterfeit FTDI. The CH340G is a good product, the counterfeit FTDI is not.

Could you make a photo of your Nano ? The serial-usb chip is probably on the backside. Can you give a link to where you bought it ? The Arduino Nano could be a Pro Micro with the ATmega32U4. You did not confirm that it is a ATmega328P. Could you measure the voltage 5V pin when everything is running ?

Thanks for the effort but I will dump the Radiohead Library as the TMRh20/ManiacBug library is working fine.

This morning when turning the Mega, Uno and Nano on with yesterday's working Sketches, they are ALL showing "sendToWait failed" so obviously something to do with the RH Library. I used the "GettingStarted_CallResponse" and other examples from TMRh20 and they are all working fine.

Definitely not the hardware so will not waste more time with that Library. It's a pity as I preferred the RH Library functions.

I agree, sometimes it better not to waste more time.

Some Nano clones have poor decoupling on the 5volt supply (oscillating regulator).
Try a 10uF or so from the 5volt pin to ground, directly on the Nano board pins.