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Topic: NRF24L01 capacitor problem!!! (Read 12357 times) previous topic - next topic

DimitrisTzam

Hi
I have made a sketch with nrf24l01 and it had many errors in signal . It loose signal very often so I soldered a 100uf ceramic capacitor and works pretty good but it rarely loose the signal again what can I do for this problem?

Wawa

100uF ceramic capacitors are rare.
Did you use a 100n ceramic capacitor or a 100uF electrolytic capacitor.
Leo..

DimitrisTzam

It writes 100k and it's ceramic

Wawa

That's most likely 100n.

No experience with adding caps to these modules, but I see recommended values of ~10uF electrolytic.
That's 100x the value you have now.
Leo..

DimitrisTzam

Electrolytic is better for ceramic in this case?

groundFungus

#5
Sep 13, 2015, 02:10 pm Last Edit: Sep 13, 2015, 02:32 pm by groundfungus
10 micro-farad is better than 100 nano-farad in this case.  It is the capacitance that matters, not, so much,  the material.  The module current requirement rises sharply while transmitting.  The cap acts as a "pool" to draw the extra current from so the supply voltage doesn't dip.  So the larger capacitance will keep the supply voltage steadier.

DimitrisTzam

Thank you very much for your reply it was really helpful

DimitrisTzam

I added 10uf but against the same

Grumpy_Mike

I added 10uf but against the same

What does that mean?

I would use both your original 0.1uF and your 10uF in parallel. It is normal that you need to add capacitors it is not a fault.

DimitrisTzam

Why I should solder two capacitors?

groundFungus

#10
Sep 13, 2015, 10:23 pm Last Edit: Sep 13, 2015, 10:25 pm by groundfungus
What are you using to supply the 3.3 volts to the nrf24.  In my experience the 3.3 volt supply on an Uno (50 mA) is not enough even with the 10uf cap.  I use a LM1117 3.3  regulator fed from 5V with 10uf tantalum cap and have good results.  I don't know if the tantalum is the right choice, but it is smaller than an electrolytic and seems to work well.


As to why both caps: the 100 nf to filter higher frequency noise (decoupling) and the 10 uf  to supply higher current demand.

DimitrisTzam

I supply one nrf from uni and the other from arduino pro mini

Grumpy_Mike

Why I should solder two capacitors?
Because this is electronics and that is what you do. If you don't like it then take up knitting.

DimitrisTzam

Ok thank you very much for your reply

DimitrisTzam

I soldered one 100n  ceramic and one 10uf electrolytic capacitor but against the same problem

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