5
\$\begingroup\$

I have a 5V Arduino Pro Mini that I want to connect with this 3.3V nRF24L01+ module. (On the other end I have the same nRF24L01+ module connected to an Arduino Uno which has a 3.3V pin that I know is safe to use.)

The nRF24L01+ modules I have are these.

The Arduino board this question relates to is this one.

\$\endgroup\$
1
  • 1
    \$\begingroup\$ The short solution is to power the RF module with two AA batteries. Long term, I'm going for 3.3V Arduinos instead of 5V. \$\endgroup\$
    – Fredrik Wendt
    Commented Jan 8, 2013 at 21:06

2 Answers 2

Reset to default
6
\$\begingroup\$

You could use a 3.3V voltage regulator. See DigiKey parts here. It looks like all of them accept a 5V input and I set a 20mA output minimum (the max supply consumption of your module is 13.5mA)

\$\endgroup\$
3
  • \$\begingroup\$ Thanks, this I see as a proper solution. In the end I opted for 3.3V Arduinos instead. \$\endgroup\$
    – Fredrik Wendt
    Commented Jan 8, 2013 at 21:07
  • \$\begingroup\$ Is there a reason you couldn't just add a resistor to bring down the voltage? \$\endgroup\$
    – DominicM
    Commented Jan 18, 2014 at 22:45
  • \$\begingroup\$ @DominicM You can't just add a resistor to bring down the voltage because the current consumption is not constant - it goes from almost 0 (in which case the voltage drop over the resistor would be 0 as V=IR). A red LED plus a ballast resistor to ensure 1mA minimum current might work, as the LEDs are typically specified as 1.8V drop and 20mA current. \$\endgroup\$
    – hifkanotiks
    Commented Apr 14, 2016 at 17:55
2
\$\begingroup\$

I've supplied my 3.3V GPS module from a 5V ATMega328 by using two 1N4001 diodes in series. It was not an optimal solution at 3.0V, but it was cheap and I had the diodes laying around.

The same solution may possibly work as a temporary hack if you need something immediately and don't want to wait on an order from a supplier.

\$\endgroup\$
2
  • 1
    \$\begingroup\$ At 10 to 20ma max, the drop should be ~0.72v on each, so it should give 3.5~3.6v. Which is perfect for OP. \$\endgroup\$
    – Passerby
    Commented Jan 8, 2013 at 1:49
  • \$\begingroup\$ Nice quick solution. I opted for 2 AA batteries though. \$\endgroup\$
    – Fredrik Wendt
    Commented Jan 8, 2013 at 21:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.