Which are the *best* NRF24L01+ modules?

Zeph

Wow, what a mess to sort out.

A given module may have

genuine Nordic nRF24L01+
genuine Nordic nRF24L01 (no ESB, no 250Kbps) - possibly marked as +
quality clone of either, possibly even out-performing Nordic in some way
(some have higher RF power output)
clone with inverted OTA ack bit (ESB OK between same, incompatible with Nordic)
clone with reduced sensitivity and/or increased power usage
any of the above with missing passive components compared to Nordic reference design

Meanwhile:

We cannot count on visual inspection (Nordic is fabless, some genuine chips may differ over time) or date codes.
We do not know of register tests to distinguish differences (except L01 vs L01+)
The inverted NoAck bit could be easily tested OTA using ESB mode to a known-good module.

The packet loss testing may have value, but it can be tricky. NeverDie says " The modules seem more finicky about their orientation than others that I've tested, and moving things just a little can make for much, much worse results."

That makes comparison difficult - is a given module better/worse than another, or was it it moved "just a little"? There's also the issue of intermittant interference in a crowded band.

The idea of having "screwed down" test positions as someone suggested is making a lot of sense. Maybe.

I'm wondering about the blobs that worked better than genuine/iTead nRF24L01+ (@1Mhz), is that because they are the higher powered clones? What's the power supply drain during transmit, compared to genuine?

The RFM69 family is a good alternative for most sensors, where lower data rates and (regulatory) lower duty cycles of 433/868/915 MHz bands are usually OK. If we want the higher data rates of GFSK at 2.4GHz, maybe the RFM73 is more consistent (fewer if any clones)?

NeverDie

@Zeph said:

I'm wondering about the blobs that worked better than genuine/iTead nRF24L01+ (@1Mhz), is that because they are the higher powered clones? What's the power supply drain during transmit, compared to genuine?

I wonder about that as well. For instance, the Si24R1 supposedly has a max transmit power of 7dB, which is well above the maximum of 0dB for a true NRF24L01+.

Unfortunately, I'm not presently setup to measure that, so I don't know the answer. However, the range and performance is simply so much better that I'm guessing that might be the reason for it. And if that is the reason, then great: I can dial back the Tx power when it's not needed, but it's there when it is needed.

However, I doubt it's the whole story. I also tried some high power modules with PA + LNA that I got from IC Station. These are the same modules that got top rank by a guy who reviewed a whole bunch of modules:
https://www.youtube.com/watch?v=gtM832Z0ujE
Guess what? They don't perform as well as the blob modules! At least not in my indoor test setup environment. They cost a lot more too than the blob modules. It's difficult to fathom.

Zeph

The packet loss info could be useful.

The Round Trip Time (RTT) testing would seem to make sense only if using ESB with ack and auto-retry is enabled, and there are errors which require one or more retries. Without retry, the packet should either be received in a fixed amount of time, or not received; the nRF24L01+ doesn't "think it over" for a while before deciding on weak packets. So it's just a disguised packet loss test, but harder to interpret.

If we want to test link quality, I think packet loss without retries is a the measurement.

And there should often be different packet losses with short and long packets. Long packets are more likely to get corrupted and lost (failing the CRC test).

Zeph

@NeverDie So you've received two orders of blob modules which work well, from different sources?

Where did you order them from? I'm interested.

NeverDie

@GIEL said:

@NeverDie

NORDIC has on their Website the option to raise questions (MyPage) which are handled by their Tech Support Team. Normally they reply fast.

It worked! I provided them with photos of the chips from the Itead modules. Here is their reply:

"
Hi,

We are not aware of any fake chips with these markings as of today, but if you want us to investigate further we need samples here for x-ray.

It is also possible that the modules has not been properly tuned (e.g. matching network and antenna) during development of the module. You will need access to a spectrum and network analyzer for proper measurement.

Best regards,

Kenneth"

I need to move on. It is not worth my time to pursue this further.

Moshe Livne

@NeverDie oh come on! Do it! Do it! :smile:

NeverDie

@Zeph said:

@NeverDie So you've received two orders of blob modules which work well, from different sources?

Where did you order them from? I'm interested.

I originally received two modules from: http://rayshobby.net/rftoy/ when I purchased my RFToy.

I received 10 from http://www.ebay.com/itm/301378218320, of which I've tested two, and they seem the same.

These I haven't tried: http://www.ebay.com/itm/301402792434 but looking at the photos they look the same to me.

So, for the NRF24L01+, if you can call it that, this "blob module" is my final choice. In my rough-and-ready testing, it stood out from the rest. If you decide to get it, I'd be curious if you, or anyone, can figure out what it actually is. It can't do 250Kbps. I anticipate I would run it at 1Mbps only.

If it weren't for the RFM69HW, I would buy more. I'm waiting to see whether I like it more.

NeverDie

Looking at the datasheet for the RFM69, I notice the maximum datarate is 300kbps. So, at least on paper, I get the impression the NRF24L01+ wins on power efficiency, but the RFM69 can offer greater range. Is that right? Is that the main tradeoff between the two?

Zeph

The RFM69x operates in one of three smaller frequency bands (ie: fewer available frequencies): 433MHz, 868 MHz (Europe), 915 MHz (US).

While there are supposed to be scores of independent channels for the nRF24 on the wider 2.4GHz band, there isn't as much room on the lower frequency bands. So 300 KBps is more of a theoretical limit; mostly the RFM69 is used for lower bit rates than that, with correspondingly lower bandwidth - and thus higher range! Unlike the nRF, you can trade off bit rate & bandwidth vs range (at any given power).

For most sensor networks, I think the RFM69 will have plenty of data bandwidth and better range (at say 56Kbps or so). For a good example, see the JeeNodes (which used the RFM12B but are migrating to the RFM69x which fits the same niche but is a better chip). JeeNodes fit a niche very similar to MySensors in that there are distributed sensor nodes communicating with a central hub, with some of the sensor nodes sleeping most of the time to save battery power. (JeeNodes are not as well integrated into common Home Automation systems, but we are now talking more about hardware and protocols).

I also use the nRF for holiday lighting control, which is more bandwidth hungry. For that the higher speeds are required. In this case a master is blasting data as fast as it can to one or more slaves; the slaves don't need to respond much, and if they do they can be polled with the Master so the master doesn't broadcast at the same time. (If using nRF for MySensors too, obviously they need to be on different channels).

There is some usefulness to me in using nRF24L01+ for both, so the same node hardware can potentially be re-purposed; it's only a firmware (and channel) change to switch between these networks. But I'm rethinking this and wondering about switching sensors to the RFM68x.

I'm not sure about power efficiency. An analysis will depend on how often the node needs to be powered up and for how long, as well as the sleep current. JeeNodes are also pretty careful about power.

Zeph

@NeverDie

So, for the NRF24L01+, if you can call it that, this "blob module" is my final choice.

They are sounding potentially attractive. Here is some of what I am wondering.

Do they take more power when transmitting? When receiving? (Should be fairly easy to test) When sleeping? (Harder, needs micropower sensor)
Do they test (via registers) as nRF24L01 or nRF24L01+? And in particular, do they implement all the plus features (like ESB mode) other than the missing 250 Kbps data rate?
Are they compatible over the air with the Nordic chips (at 1Mbps/2Mbps)? In general, and in terms of using ESB mode. At least one clone/derivative chip got the NoAck bit (as sent over the air) reversed from Nordic, due to an error in the Nordic datasheet. (We don't see that in the registers, it only shows up in the OTA packet).

It would be good to be compatible with Nordic (and good clones), so that (1) we can swap in/out with other nRF chips we already have or purchase in the future and (2) in particular we can use the higher powered LNA+PA+antenna versions for a gateway or hub, which are not available in blob form AFAIK.

Do you have any answers to any of these yet? Anybody else? If they have ESB and are compatible OTA with Nordic, I think they are very attractive; the power usage is a secondary concern, and only for some nodes.

NeverDie

I don't at present know any of those answers. However, I am interested in power consumed. Also, at present I'm less concerned about interoperability than I am about range and not having to aim the antenna so precisely.

NeverDie

@Zeph said:

@NeverDie

So, for the NRF24L01+, if you can call it that, this "blob module" is my final choice.

They are sounding potentially attractive. Here is some of what I am wondering.

Do they take more power when transmitting? When receiving? (Should be fairly easy to test) When sleeping? (Harder, needs micropower sensor)

Do they test (via registers) as nRF24L01 or nRF24L01+? And in particular, do they implement all the plus features (like ESB mode) other than the missing 250 Kbps data rate?

Are they compatible over the air with the Nordic chips (at 1Mbps/2Mbps)? In general, and in terms of using ESB mode. At least one clone/derivative chip got the NoAck bit (as sent over the air) reversed from Nordic, due to an error in the Nordic datasheet. (We don't see that in the registers, it only shows up in the OTA packet).

It would be good to be compatible with Nordic (and good clones), so that (1) we can swap in/out with other nRF chips we already have or purchase in the future and (2) in particular we can use the higher powered LNA+PA+antenna versions for a gateway or hub, which are not available in blob form AFAIK.

Do you have any answers to any of these yet? Anybody else? If they have ESB and are compatible OTA with Nordic, I think they are very attractive; the power usage is a secondary concern, and only for some nodes.

@Zeph: Regarding #2: What is ESB mode? To what degree does the mysensors code rely on those things being true? i.e. do certain clone/fake chips "break" the mysensors code, or do they just run less efficiently?

So far I haven't noticed incompatibility between the blob modules and other modules. I haven't extensively tested, though, so it's more of a casual observation. The data seems to get through. That said, I'm going to use only blob modules, so it's a moot issue to me. If it were a concern for you, they're cheap enough you could probably just replace whatever modules you have with blob modules, and then those potential issues disappear. Ironically, the only way to be certain all your modules are of the same type may be to use blob modules! Otherwise, as you outlined earlier, it's really hard to know what chip you actually have on any given module. I have less confidence in how randomly different chips might interoperate than when chps are all of one type, whatever that may be.

I'm going to switchover from using Mirf (which got me started) to the same library mySensors uses :tmrh20. Then I'll be better able to run more detailed tests that are directly relevant. Either before or after that I'll try to measure power consumption, especially transmit power.

hek

Got the microscope today. This is a closeup of the genuine NRF-chip.

Daniel Oliveira

Hi everyone!

I bought some NRF24L01+ that have the Range Extension chip RFaxis RFX2401C

I'm curious to see how they perform :)

And for that I'm thinking in rewriting the RFToy Sender/Receiver examples with the MySensor libraries.
This will allow me to learn about the MySensor libraries and also to test the "performance" of the RF modules with different configurations.

What do you think? Let me know if you're interested in such code.

Regards

NeverDie

@Daniel-Oliveira said:

Hi everyone!

I bought some NRF24L01+ that have the Range Extension chip RFaxis RFX2401C

I'm curious to see how they perform :)

And for that I'm thinking in rewriting the RFToy Sender/Receiver examples with the MySensor libraries.
This will allow me to learn about the MySensor libraries and also to test the "performance" of the RF modules with different configurations.

What do you think? Let me know if you're interested in such code.

Regards

Yes, definitely! I'll also be very interested to hear about the performance of your range extended modules.

NeverDie

I took a quick stab just now at using a Dave Jones uCurrent and an oscilliscope to measure the current on an NRF24L01+, but there was too much noise. I suspect long wires are contributing to the problem. I'm inclined to think some kind of onboard measurement by the arduino itself is the way to go, as then the wire lengths are short. Not sure how other people are rigging to do it, but so far measuring NRF power consumption seems a lot easier said than done.

Yveaux

@NeverDie just some tips when measuring small currents:

use a stable power supply (e.g lab supply). Don't power from you pc or cheap switching powersupply.
twist the leads to the current.
use your scope to filter noise or add a lowpass filter using a capicitor+resistor on the signal going from the ucurrent to your scope

NeverDie

@Yveaux said:

@NeverDie just some tips when measuring small currents:

use a stable power supply (e.g lab supply). Don't power from you pc or cheap switching powersupply.

twist the leads to the current.

use your scope to filter noise or add a lowpass filter using a capicitor+resistor on the signal going from the ucurrent to your scope

Thanks! Those are useful suggestions on how to proceed.

On my first attempt last night I used an Arduino Uno to drive the NRF24L01+. I eventually noticed that even without plugging the USB cable into my computer that the USB cable was a big source of noise when plugged into the Uno. When I did plug the USB cable into my computer, the noise got much worse. So, the USB cable has got to go.

New plan for the second attempt::

Use an RFToy, instead of Uno, because it's a more compact way to plug-in the NRF24L01+ without having wires dangling all over, and because it can run off a coin cell battery, again without wires.
Plug the NRF24L01+ into "tall" female header pins, and then plug those into the usual 2x4 header on the RFToy. Why? Because the leg of the tall VCC header pin I'm going to snip and (hopefully) replace with a 1 ohm sense resister. With luck there will be enough room on either side of the inline sense resister to connect up the oscilloscope and thereby do measurements without introducing long wires that might pick up noise.

NeverDie

BTW, I notice ManiacBug measures transmitter current with just a $50 multimeter and setting "endless trasmitter" mode. https://maniacbug.wordpress.com/2011/10/19/sensor-node/

Not sure how accurate that is though.

NeverDie

Lastly, I notice these "Noise Cancelling Techniques" from an Attiny datasheet, regtarding ADC measurements:
"Digital circuitry inside and outside the device generates EMI which might affect the accuracy of
analog measurements. When conversion accuracy is critical, the noise level can be reduced by
applying the following techniques:
• Keep analog signal paths as short as possible.
• Make sure analog tracks run over the analog ground plane.
• Keep analog tracks well away from high-speed switching digital tracks.
• If any port pin is used as a digital output, it mustn’t switch while a conversion is in progress.
• Place bypass capacitors as close to VCC and GND pins as possible."

Which are the best NRF24L01+ modules?

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