user24103: I'm trying to make a 4 channel RC using Arduino and nrf24L01 module.
I already know how to deal with this module, but the question is "What does 4 channel mean ?", and how to make it supports 4 channel ?  

user4143: 4 channel means having the ability to send 4 individual values (maybe speeds?) at once.
Since the nRF24L01+ is a packet based system it is as simple as sending the different "channels" as different bytes (or groups of bytes if more than 0-255 or -128 to +127 is needed).
For instance, if you want 4 channels that can represent 0-255 then you need 4 bytes, and so you can set both sender and receiver to have a packet size of 4 bytes (for efficiency) and send a packet made up of the 4 channel values.
If you want to represent numbers bigger than that then you need to split the variable into bytes (two bytes for an int, 4 for a long) or create a struct to represent your packet of data. Of course you then need the sender and receiver to be set to a packet size at least big enough to contain the data, and both ends must agree on the packet size.

24103: <p>I'm trying to make a 4 channel RC using Arduino and nrf24L01 module.
I already know how to deal with this module, but the question is "What does 4 channel mean ?", and how to make it supports 4 channel ?  </p>
 4143: <p>4 channel means having the ability to send 4 individual values (maybe speeds?) at once.</p>

<p>Since the nRF24L01+ is a packet based system it is as simple as sending the different "channels" as different bytes (or groups of bytes if more than 0-255 or -128 to +127 is needed).</p>

<p>For instance, if you want 4 channels that can represent 0-255 then you need 4 bytes, and so you can set both sender and receiver to have a packet size of 4 bytes (for efficiency) and send a packet made up of the 4 channel values.</p>

<p>If you want to represent numbers bigger than that then you need to split the variable into bytes (two bytes for an int, 4 for a long) or create a <code>struct</code> to represent your packet of data. Of course you then need the sender and receiver to be set to a packet size <em>at least</em> big enough to contain the data, and both ends must agree on the packet size.</p>
