Problem with NRF24L01+ clones

[vsimko]

I bought two versions of the NRF24L01+ module, both from China. The cheaper version, however, causes problem when transmitting.

This one works

This version does not work (although there are indistiguishable versions that do work, see below)

Notes

• If I use the library nRF24L01p_SoftSPI and try to transmit some data, the whole Arduino hangs and disconnects from USB.
• With the RF24 library, the transmission does not freeze the MCU but nothing is being transmitted.
• I can, use both versions with the RF24 as a receiver, however ACK needs to be disabled. I suspect that this might have something to do with Si24R1 chip that has ACK bit inverted.
• Both versions can be operated from the 3.3V pin on Arduino Nano v3 but the PA Level needs to be RF24_PA_LOW.
• By providing a separate 3V source to the fully working module from 2xAA batteries (with GND shared with Arduino), I could use RF24_PA_HIGH, but never RF24_PA_MAX.

[vsimko]

From section 10.4 of the Nordic Semiconductor spec sheet for the NRF24L01+:

"The nRF24L01 DC supply voltage should be decoupled as close as possible to the VDD pins with high performance RF capacitors, see Table 26. on page 69. It is preferable to mount a large surface mount capacitor (for example, 4.7μF ceramic) in parallel with the smaller value capacitors. The nRF24L01 supply voltage should be filtered and routed separately from the supply voltages of any digital circuitry."

[vsimko]

See also this post: http://forum.mysensors.org/topic/1153/we-are-mostly-using-fake-nrf24l01-s-but-worse-fakes-are-emerging

[vsimko]

I don't want to waste time with the cheap buggy units. I just ordered a new set of the working "YJ-15008+PA" units from eBay (2.90 EUR each)

[vsimko]

Interestingly, when the new units arrived, they looked exactly as those cheap non-working clones, although I ordered specifically the model with "YJ-15008+PA" marking on it. However, these units are working. Only 1 of these 28 units doesn't work, but that's probably a different story.