A small NRF24L01 chip comparison
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I did a really small test today.
I used the 'Poor man's 2.4Ghz signal scanner' sketch. It uses a NRF24L01 module to scan over all channels and outputs detected signal.
The different modules showed very different outcomes.
The question I have for you is: what do you think the outcome means?
The setup
- All of them were just switched out in an Arduino Nano Wireless Expansion board. This means no problems with cables being faulty or influential.
- All done in the same place, minutes after each other.
The results
Normal cheap fake Chinese NRF24 chip:
Starting Poor Man's Wireless 2.4GHz Scanner ... 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 123587655966757455132 1 2359989895968855221 1 144558798968988393221 168798898997878889763 2677568777656798422 2222211 5596555588588788313 1 11222 1 234668658895444644121 11111 216379998769747856211 11111 232467679787552441111 4443311 135555678997989876211 1111111 233788599996898954232 21111 1 113775979888467897121 2221111 125587758989898855531 2221111 4656968897965768666731 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 13473956666856578541 1 113777868799744534111 1 112499646766534421111 1 111 9989688988886861 1 56615 223878776759888974122 11211 125657977675665743321 2 113557469867769763321 111 1 33658858598988964321 11 1 114878689797866874211 111Version with shielding:
0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 1215966666857998343 121 1376878786977999755 1 1 1111 111 11 2445577867769588421 122 1334667477796796662 221 1136479988777987555 222 147799989898976664 334 133758796979783211 335 1355899899798899752 111 365888878855985431 1 11 11 333 1 1568968776778988551 111 1267888888889998866 111 1221976859875451212 222 233877978978787332 433 111 1255666757789797665 111 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 1255876988888888442 211 1244685977868765554 112 1 2233677967987656433 222 127665987998876331 324 1134676899968987421 212 1 145885777978896533 212 1 1254665667876999873 1 222 1 1212565395568956161 211 285577995686978552 222 13226585857676965221 111 1145757799786786443 111 1256566669888779854 111 368999888999889996 111 255879987887688764 111 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 1377999898998987877 111 111 1468899988987787774 111 2348999888686682265 46611 1 3448898876668887655 1 1 3466999976798767442 1136786878897741321 1 1 1115746669876995 32 1 1 23456888676989944631 11 1343769686685686642 1353476888596978443 11 35657577578979898651 111 34557698689997987851 1 1 1 3558589877997776574 1 11 33536788987786895651 11 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 5468968989666866541 1 1 47659988998797776452 112 1 35659796978787684431 211 1 11 24547766665799943541 212 1 1556975769999997754 2 1 3435675787977674631 111Shielded with antenna:
Starting Poor Man's Wireless 2.4GHz Scanner ... 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 111111111111111111111111111111171111111111111119111 1111111481111111111111111 11 111111111111111111111111111111191111111111111 1911 1111111991111111111111111 11 111111111111111111111111111111191111111111111 19111 111111199111111111111111111 11 111112122222222231111111111111171111111111111 19111 1111111291111111111111111 11 222222233433343343222222222211191111111111111 19111 11111115811111111111111111 22 111111122222222222111111111111191111111111111 191 1111111591111111111111111 11 11111111111111111111111111111116211111111111111911 111111129111111111111111111 11 111111111111111111111111111111151111111111111 1911 1111111191111111111111111 11 111111111111111111111111111111161111111111111 1911 11111111911111111111111111 11 112222233323333332122112121111162111111111111 1911 111111119111111111111111 11 11 111111122222221221111111111111181111111111111119111 1111111191111111111111111 11 1111111111111111111111111111111711111111111111191 1111111191111111111111111 11 111111121121111111111111111111181111111111111 19111 1111111291111111111111111 11 111111122222122222111111111111161111111111111119111 1111111291111111111111111 1 11 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 111111111111111111111111111111161111111111111 191 111111119111111111111111111 11 1111111112211121211111111111111711111111111111191111 1111111111911111111111111111 11 111111111111111111111111111111191111111111111 191 11111115811111111111111111 11 1111111222222222221111111111111911111111111111191 1 11111116711111111111111111 11 111111111111111211111111111111191111111111111139 1111111831111111111111111 11 111111111111111211111111111111161111111111111119 11111114811111111111111111 11 11111111111111111111111111111119111111111111113911 1111111781111111111111111 1 11 111111132222222222111111111111191111111111111119111 1111111581111111111111111 1 11 111111111111111111111111111111191111111111111119111 1111111391111111111111111 1 11 111111111111111111111111111111191111111111111 19 1111111291111111111111111 11 111111111211111111111111111111191111111111111 1911 1111111391111111111111111 11 111111111111112221111111111111191111111111111 191 1111111491111111111111111 11 111212223222223222111111111111191111111111111119111 1111111291111111111111111 11 223233343343443433222222222111191111111111111 19 11111112911111111111111111 12 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 111212233332222333222121111111191111111111111 19 11111113911111111111111111 11 11111222323323332222211111111113111111111111117711 111111192111111111111111 11The EBYTE small red modules:
0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 1111111212111111111 11 11233111111 111 49 111111111111 11 1 111111112121111111 111233111111 11 19 111111111111 11 112211223111111111 1 111122111111 111 39 11111111111 1 112122222221222211 1 11 22344111111 1111 19 111111111111 1 1111112121111111 1 1 1113331111 1111 98 1 11111111111 11 111211112111111 1 12344111111 11 99 11111111111111 1 1 111111111111111 1 1111111111 111 95 111111111211 1 1 11 111111111111111 1 1 11222111111 1111 94 111111111111 11 113333434332211 1 12444111111 111 92 111111111111 1111111112111111 1 111444111111 1111 92 111111111111 111 1111111111111111111 11 11221111111 1111 91 11111111211 111 222323435332211111 111 125562111 111 9 11111111111 111111111111111111 1 1 111211111 111 91 111111111111 1 111111111111111 11 11 11223111111 11 91 11111111121 1 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111 0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567 1111112221223232122 1 11666221211 211 91 111211111211 111111111212121111 1 1 11333111111 11 91 111111111111 1 11111111111111111111 1111 11222111111 1111 92 111111111211 1 11111111111111111 11111111111 11111 91 1111111112111111 111111111111111111 11 11111111111 11111 91 111111113111 1111111111111111 111 1 1 11332111111 11111 89 111111111111 11 111111111111111 1 111111111111 11111 93 111111111211 1 1 1111111111111111 1 1 111211111111 1111 91 111111111111 11 11111111111111111111 11 112221111 1 1111 94 111111111111 11 11111111121111111 11 111 11221111111 111 91 1 11111111111 11222212424232212 11233311 1 1 11111 1 91 1 1111111121 1 111111112111211111 1 11 1122111 1 1 11 93 1 111111111211 111 1111111121111111 1 111111111111 1111 92 11111111111 1 1111112112222221111 111 1 11322111111 1111 93 111111111111 111
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@alowhum this method uses the received power detector function of nrf24 modules, which just scans a channel for some time. If in this time frame a 'strong' signal is detected it will count as one. It's not as fancy as RSSI for instance, and is influenced by antenna type, orientation and preamp.
I recently did some tests and can clearly detect eg wifi activity, strongly influenced by heavy wifi traffic. Try starting a speedtest on your mobile phone while running the scan
As the spectrum changes over time comparing in detail will be hard, but wifi channels will show up clearly if you scan long enough.
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@alowhum By the way, I finished an extension for the nRF24Doctor about a week ago to display the nRF24 received power spectrum:
Between channels 0 and 125 you see a little 'chart' which has a clear peak around the center. The little dot above the chart is an indicator which shows the selected channel (61), frequency (2.461GHz) and Wifi channel (11) at the bottom row.
The peak in the chart is caused by my Wifi at channel 11
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My assumptions are:
- More data in a line means there is more range: it picks up more signals.
What I take from this is:
- The version with shielding has surprisingly poor range.
- The version with an antenna (not the PA version!) has a lot of range. But it's expensive.
- The eByte module has a lot of range for the price.
Other thoughts:
- The first two pick up a signal in channel 61
- The eByte picks up a strong signal in channel 62, later shifting to channel 61. It picks it up ridiculously strongly (a score of 9). Is it picking up its own signal perhaps?
- Oddly enough, the antenna version seems to think the same signal is on channel 64.
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@alowhum said in A small NRF24L01 chip comparison:
My assumptions are:
- More data in a line means there is more range: it picks up more signals.
More data in a line means this channel has higher occupation; other devices are using the same channel and you'd better choose an empty channel for your nRF network (like 85 and up).
What I take from this is:
- The version with shielding has surprisingly poor range.
Doesn't make much difference I would say; it has lower sensitivity in neighbouring channels though.
- The version with an antenna (not the PA version!) has a lot of range. But it's expensive.
Remember, this tests receive only, so no clue on transmit range.
- The eByte module has a lot of range for the price.
That I knew already
Other thoughts:
- The first two pick up a signal in channel 61
They all do
- The eByte picks up a strong signal in channel 62, later shifting to channel 61. It picks it up ridiculously strongly (a score of 9). Is it picking up its own signal perhaps?
No, it's receiving only. Maybe some frequency hopping node nearby (bluetooth -- https://www.youtube.com/watch?v=6qNWQxRKoss) ? Smartwatch?
- Oddly enough, the antenna version seems to think the same signal is on channel 64.
These are snaphots of on-air traffic that vary over time.
If traffic was really at channel 61 and it received at channel 64 that module would not be able to communicate with other modules at the same channel.
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@yveaux Can I ask for the code with you.
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@jhjjacky Here you are: https://github.com/TechNovation01/nRF24Doctor
See also this thread: https://forum.mysensors.org/topic/9178/nrf24doctor
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@yveaux Thank you
