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I am a high school student and I need to build a remote controlled car for a school project and I have to use arduino. I am fairly new to arduino, but I understand the basics. Also I'm kind of desperate so please read until the end.

The part I am using is the NRF24L01 transceiver and to learn how it works, I copied a bare-minimum code from https://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-ExampleSketches#bm1. When I started the code, the "RF24/Simple Transmit data Test" and "Questions: terry@yourduino.com" showed up as black diamonds with question marks inside in both the Transmitter and Receiver serial monitors.

The transmitter kept showing these question marks with random letters through out the entire code.

The receiver showed (like it was supposed to) "Data received = ", but the number it equaled was not correct. Here is a picture Arduino Receiver

I looked at the code for a difference between the part that worked and the parts that didn't and found that the Serial.print (F())'s didn't work and the Serial.print() did. I don't know what the F does except that it send flash data and I don't know what that means. I got rid of all the F's and transmitters Serial monitor looks perfect, but the Receiver only shows that beginning text and doesn't receive and numbers. I put a Serial.print in the if to see if it gets in, but it doesn't.

I've had this problem for a couple of days and need to get it fixed otherwise I can't finish the rest of the car! I need to bring it to class on Monday.

closed as unclear what you're asking by Chris Stratton, Mattia, Paul, Nick Gammon Jun 4 '16 at 5:38

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • Arduino (actually the Atmel processor) does not contain a lot of RAM. So you can store strings in flash using "F()" instead of using RAM. The odd characters sound like the baud rate is incorrect. Both Rx & Tx code are setting the baud for 115200. Make sure you copied that correctly and that the terminal programs you are using are also setup accordingly. If that doesn't help drop the baud rate to something slower and try again. – st2000 May 1 '16 at 3:07
  • Your receiver is wrongly wired, insufficiently or badly powered or counterfeit. Check wiring, then decouple the power supply and make sure it can supply either 14mA for standard model or ~150mA for PA one. – Avamander May 1 '16 at 14:48
  • Voting to close this question as it is unanswerable because in three weeks you have failed to add to your posting any of the necessary details of the circuit or software which could help identifying the problem any more specifically than the suggestion already made. A question on a stack exchange site should present the key information necessary to answer within the body of the question itself. – Chris Stratton May 22 '16 at 20:23