Also, for those wondering how to set up the USB CH340T/NRF24L01+ transceiver module ..... I have some details here....
For this particular test....the USB ch340T/nrf24L01+ 'dongle' connected to the computer will be used to receive messages from the arduino wirelessly (even though it has absolutely no trouble sending messages to the arduino).
Once this USB dongle is plugged into the computer, such as a Windows Operating system computer, it's necessary to then use a Serial Communications terminal software like PuttY or Termite to check out the communications settings. I believe that the default baud rate for the dongle is 9600 baud. But obviously, it's also necessary to know which serial communications port is assigned (automatically) to this dongle. So might need to use Device Manager (in windows) to see what 'COM' port was assigned to the dongle in order to communicate with it through the serial monitor terminal.
Can assume that everybody will be able to use a serial communications terminal window to link up with the USB dongle (if they have one of these devices). Let's assume that the serial link is established.
So, in the terminal window, type AT? and hit the enter key. Hopefully some garbled characters will show up, with some recognisable values like '9600' (for baud rate), and '16' (for default CRC length), and '2Mbps' (for 2 Megabit per second radio frequency data rate), etc.
I set the receive pipe address by typing:
AT+RXA=0x41,0x41,0x41,0x41,0x41 then hit enter
Note that the above hex code is really "AAAAA" in ascii
Next, I set the transmit pipe address by typing:
AT+TXA=0x41,0x41,0x41,0x41,0x42 (which is "AAAAB" in ascii), then hit enter
Noting in the above that the "transmit pipe address" that we set in the dongle is really the DESTINATION address. So basically, it is the 'transmit to WHERE?' address.
Then, I'm using channel '4', which is 2.404 GHz or 2404 MegaHz.
To set this in the dongle.... type this:
AT+FREQ=2.404 then hit enter.
In the end....just type AT? again (and remember to hit enter key) to check on the settings.
A list of settings will pop up.... like..
ϵͳÐÅÏ¢£º
²¨ÌØÂÊ£º9600
Ä¿±ê¶Ô·½µØÖ·£º 0x41,0x41,0x41,0x41,0x42
±¾µØ½ÓÊÕµØÖ·0£º0x41,0x41,0x41,0x41,0x41
¹¤×÷ƵÂÊ£º2.404GHz
УÑ鷽ʽ£º16λCRCУÑé
·¢É书ÂÊ£º0dBm
¿ÕÖд«ÊäËÙÂÊ£º2Mbps
µÍÔëÉù·Å´óÔöÒ棺¿ªÆô
Ignore the garble, as the encoding is reported to be chinese characters.
The first pipe address is the TRANSMIT pipe address (ie. the destination address for the message to be sent, which is going to be the address that the arduino is going to be listening at). So..... at the USB dongle CH340T/NRF, the transmit pipe address is set to "AAAAB" (aka hex 0x41,0x41,0x41,0x41,0x42), and the receive pipe address is set to "AAAAA".
The address on the line below it is therefore the receive pipe address, which is what the dongle will be listening on.
By default, the USB dongle will already have a CRC length setting of 16, and will already have a 2 Mbps radio frequency data rate. So once these settings are ok, then it will be just a matter of focusing on the OTHER (ie. arduino) side of things.....eg... loading the sketch, and making sure you have the "RF24" library included with your arduino library. After loading the arduino code to the arduino, just use the arduino IDE serial monitor terminal, and hit 't' (and enter key) to start transmissions. Then, using another serial monitor window to monitor the activity on the USB dongle side, the incoming characters should start coming in every 1 second or so.