Initializing RF24 radio causes pins to lower voltage output

Hello all- I’m having a very strange issue with an Arduino Nano and NRF24L01+ radio. I’m using the RF24 library, but when I create a new radio object with

RF24 radio(ce, csn);

, all of the Nano’s pins start outputting 3.3V instead of 5V. I tested this with a piezo to make sure. I have no idea why this is happening, and it happens independent of whether the radio is actually connected or not. Is this a bug, or am I just stupid and missing something? Any help would be appreciated.

The NRF24L01 is a 3.3v device. Have you connected its power supply pin to 5v on your Nano?

It helps if you provide details on how you connected the NRF24L01 to your Nano.

w1skija:
, all of the Nano's pins start outputting 3.3V instead of 5V.

What caused you to measure the voltage? I have been using nRF24s for a few years now and it has never occurred to me to measure the voltage.

Have a look at this Simple nRF24L01+ Tutorial.

Wireless problems can be very difficult to debug so get the wireless part working on its own before you start adding any other features.

The examples are as simple as I could make them and they have worked for other Forum members. If you get stuck it will be easier to help with code that I am familiar with. Start by getting the first example to work

There is also a connection test program to check that the Arduino can talk to the nRF24 it is connected to. If the first example does not work be sure to try the connection test for both of your Arduinos. Nothing will work if the connection test fails.

A common problem with nRF24 modules is insufficient 3.3v current from the Arduino 3.3v pin. This seems to be a particular problem with the nano. The high-power nRF24s (with the external antenna) will definitely need an external power supply. At least for testing try powering the nRF24 with a pair of AA alkaline cells (3v) with the battery GND connected to the Arduino GND.

...R

Oops, I mis-read your post. So this happens when the NRF24L01 module is disconnected. What happens when you have nothing connected to the Nano?

markd833:
The NRF24L01 is a 3.3v device. Have you connected its power supply pin to 5v on your Nano?

It helps if you provide details on how you connected the NRF24L01 to your Nano.

It's connected to the 3.3v pin. However, whether or not it's connected doesn't seem to matter for this issue.

Robin2:
What caused you to measure the voltage? I have been using nRF24s for a few years now and it has never occurred to me to measure the voltage.

Have a look at this Simple nRF24L01+ Tutorial.

Wireless problems can be very difficult to debug so get the wireless part working on its own before you start adding any other features.

The examples are as simple as I could make them and they have worked for other Forum members. If you get stuck it will be easier to help with code that I am familiar with. Start by getting the first example to work

There is also a connection test program to check that the Arduino can talk to the nRF24 it is connected to. If the first example does not work be sure to try the connection test for both of your Arduinos. Nothing will work if the connection test fails.

A common problem with nRF24 modules is insufficient 3.3v current from the Arduino 3.3v pin. This seems to be a particular problem with the nano. The high-power nRF24s (with the external antenna) will definitely need an external power supply. At least for testing try powering the nRF24 with a pair of AA alkaline cells (3v) with the battery GND connected to the Arduino GND.

...R

Whether or not the radio is connected doesn't affect this issue. Even without any pins connected to the radio, the line creating the radio object messes things up. I'm reusing some old rf24 code that I know for a fact works in terms of transmission.

w1skija:
I'm reusing some old rf24 code that I know for a fact works in terms of transmission.

Does the same problem arise with the library and the code used in my Tutorial?

And you have not said what caused you to think of measuring the voltages.

By the way, if the Arduino is outputting a stream of pulses on an I/O pin a mulitmeter won't read the voltage properly. A multimeter is only useful if you are sure that the I/O pin is constantly either HIGH or LOW.

...R