Most reliable "best" radio
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Well, the nRF24L01 datasheet says, "The nRF24L01 transmitter PLL operates in open loop when in TX
mode. It is important to never keep the nRF24L01 in TX mode for more than 4ms at a time."Disappointing, but I believe I can work around that limitation.
Why is there a limitation on Tx time but not Rx time? Is it a thermal issue of some kind?
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@Larson In this case, it's almost certainly the si24R1 chip, because if you look at the datasheet here: https://datasheet.lcsc.com/lcsc/1811142211_Nanjing-Zhongke-Microelectronics-Si24R1_C14436.pdf and zoom in on the electrical specification, you see that the specified currents are:
which is a very close match.
:smile:
I've written about this before (here: https://forum.mysensors.org/topic/1664/which-are-the-best-nrf24l01-modules/285 , where it took me a lot of effort to finally figure all this out), but it's so buried at this point that I doubt anyone new to the game is even aware of it. So, I include it here, as bonus perk for anyone who happens to be reading this thread. Nice, ya?
@NeverDie said in Most reliable "best" radio:
I've written about this before (here: https://forum.mysensors.org/topic/1664/which-are-the-best-nrf24l01-modules/285 , where it took me a lot of effort to finally figure all this out), but it's so buried at this point that I doubt anyone new to the game is even aware of it. So, I include it here, as bonus perk for anyone who happens to be reading this thread. Nice, ya?
Yes, very nice. But how would you know where to look for the si24R1 chip amongst the others? I haven't read the other thread, just yet - it is the end of a very long sweaty fuse-setting day. Not only just a perk, your writing on these subjects is a library for others. Like today, I'm reading Nick Gammon's posts from 2012. They are there and very relevant still - I spend much of the day reading them. In 2032, should we get that far, folks will be upstudying your material.
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@Larson Somewhere I found a list of known clones. I linked to it in the original thread that I referenced above. si24R1 is China's clone of the nRF24L01. Ebyte even explicitly advertises it as a clone on their website and in their aliexpress store. A lot of times if you see an advertisement for an "enhanced power" nRF24L01 that doesn't otherwise contain a PA, it's an si24R1, because it has a 7dBm Tx power, versus a max 0dBm Tx power for the nRF24L01.
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@skywatch said in Most reliable "best" radio:
those tiny ferrite beads
Have you tried it before? Exactly which tiny ferrite beads do you recommend? Mouser lists over 4,200 different ones.
@NeverDie I have not tried them for this particular application, but have used them for SMPSU and the larger clamp on styles for SDR and other RF devices.
They used to be quite cheap so trying a size that fits snuggly over the wires you are using should help.
I see that guy in the video you posted twisting the ground wire with the data wires. This could simply be adding capacitance to the circuit or acting as a common mode rejection against transient interference. I wonder why he didn't try different value pull-up resistors on the data lines to see if that would help.
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Well, the nRF24L01 datasheet says, "The nRF24L01 transmitter PLL operates in open loop when in TX
mode. It is important to never keep the nRF24L01 in TX mode for more than 4ms at a time."Disappointing, but I believe I can work around that limitation.
Why is there a limitation on Tx time but not Rx time? Is it a thermal issue of some kind?
@NeverDie I suspect that in 'open loop' (i.e. no feedback as I understand that to mean) then frequency stability over a longer period might be questionable. So to be safe they recommend a limit across which frequency drift won't be noticable. But as always, I could be completely wrong!
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@NeverDie I suspect that in 'open loop' (i.e. no feedback as I understand that to mean) then frequency stability over a longer period might be questionable. So to be safe they recommend a limit across which frequency drift won't be noticable. But as always, I could be completely wrong!
@skywatch said in Most reliable "best" radio:
@NeverDie I suspect that in 'open loop' (i.e. no feedback as I understand that to mean) then frequency stability over a longer period might be questionable. So to be safe they recommend a limit across which frequency drift won't be noticable. But as always, I could be completely wrong!
That's what I was thinking also, but if that were the case, why would the 4ms limit apply only to Tx and not to Rx? I guess the only way to find out is to run it longer than recommended and see what happens. In the worst case I burn out a module, but they're so cheap it would be worth the sacrifice.
What's a bit weird is that it doesn't say anything beyond not keeping it on for more than 4ms. It doesn't indicate that it needs a rest period or anything, so, yeah, I'm guessing you're right: it's some kind of frequency stability thing that mysteriously applies to Tx and not to Rx for some reason.
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By the way, if I did end up using the nRF24L01 (or nRF5x series), I'd like to do what I outlined in the last post on that thread (https://forum.mysensors.org/topic/1664/which-are-the-best-nrf24l01-modules/309?_=1654977950928), which is to do channel hopping and time synchronization among motes. There are some interesting demos on distributed time synchronization which are pretty cool:
https://www.youtube.com/watch?v=Q22TeUTTiMMOne simple (but maybe not the best technique) is to have each node transmit its local time in some kind of sequence, while the other nodes listen and take note. Then by averaging these local times over a few iterations, the group converges onto a single time. Pretty neat, huh? I would imagine that, more efficient and less complex, would be to have a powered wireless time server, and then everything syncs to that.
@NeverDie said in Most reliable "best" radio:
which is to do channel hopping and time synchronization among motes.
A guy by the name DeKay played with frequence hopping when trying to hack a Davis Pro Vantage Pro Weather station. He has several blogs about this. Here is one: [http://madscientistlabs.blogspot.com/2014/02/build-your-own-davis-weather-station_17.html] but there are others. Kobuki was one of the contributors of note.
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@Larson Somewhere I found a list of known clones. I linked to it in the original thread that I referenced above. si24R1 is China's clone of the nRF24L01. Ebyte even explicitly advertises it as a clone on their website and in their aliexpress store. A lot of times if you see an advertisement for an "enhanced power" nRF24L01 that doesn't otherwise contain a PA, it's an si24R1, because it has a 7dBm Tx power, versus a max 0dBm Tx power for the nRF24L01.
@NeverDie said in Most reliable "best" radio:
...si24R1 is China's clone of the nRF24L01. Ebyte even explicitly advertises it as a clone on their website and in their aliexpress store.
On reading the comments in one of the refered Electronoobs links, I saw that the si24R1 was celebrated. If the higher TX power demand is effective ... then it it would be good to look at. I do marvel at the value that is delivered from China. It makes it possible for me to explore without worrying too much about smoking a few chips... which I have done.
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@NeverDie I have not tried them for this particular application, but have used them for SMPSU and the larger clamp on styles for SDR and other RF devices.
They used to be quite cheap so trying a size that fits snuggly over the wires you are using should help.
I see that guy in the video you posted twisting the ground wire with the data wires. This could simply be adding capacitance to the circuit or acting as a common mode rejection against transient interference. I wonder why he didn't try different value pull-up resistors on the data lines to see if that would help.
@skywatch said in Most reliable "best" radio:
I see that guy in the video you posted twisting the ground wire with the data wires. This could simply be adding capacitance to the circuit or acting as a common mode rejection against transient interference. I wonder why he didn't try different value pull-up resistors on the data lines to see if that would help.
One of the comments I saw about this twisting technique referenced a radio tech from 50 years ago and it worked for them. I like your ideas. Is there a circuit for common mode rejection? It would be worth exploring. And using a test port for different pull-up resistors, better yet a variable resistor, would allow for testing. We have tools today to explore.
[edit: Now that I've learned from Hartley and Bogatin to think of the return path of signals, the twisting technique looks really appealing for prototype fly-wires. Is the common mode rejection an idea for more final PCB's? Or is it more of a breadboard idea?]
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@NeverDie said in Most reliable "best" radio:
...si24R1 is China's clone of the nRF24L01. Ebyte even explicitly advertises it as a clone on their website and in their aliexpress store.
On reading the comments in one of the refered Electronoobs links, I saw that the si24R1 was celebrated. If the higher TX power demand is effective ... then it it would be good to look at. I do marvel at the value that is delivered from China. It makes it possible for me to explore without worrying too much about smoking a few chips... which I have done.
@Larson said in Most reliable "best" radio:
@NeverDie said in Most reliable "best" radio:
...si24R1 is China's clone of the nRF24L01. Ebyte even explicitly advertises it as a clone on their website and in their aliexpress store.
On reading the comments in one of the refered Electronoobs links, I saw that the si24R1 was celebrated. If the higher TX power demand is effective ... then it it would be good to look at. I do marvel at the value that is delivered from China. It makes it possible for me to explore without worrying too much about smoking a few chips... which I have done.
Yes, from the standpoint of having an inexpensive transmitter without a PA the si24R1 does very noticeably outperform the Nordic nRF24L01. 7dBm vs 0dBm. I like them. Just saying that it's good to know what you have. There are known to be some imcompatabilities, but I'm forgetting among which chips they arise. IIRC, it has to do with how ACK's are handled. It can be a source of frustration if you aren't aware of it, and it doesn't help that the chip labeling may lie about just exactly what they are. I'd have no complaints if the si24R1 chips were actually labeled si24R1 instead of trying to pass themselves off as nRF24L01's by labeling themselves as such (as in the photo that I posted). Sometimes they are, but more often than not they aren't.
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Judging from the "power enhanced" title in this listing: https://www.amazon.com/dp/B082VLQK1M?psc=1&ref=ppx_yo2ov_dt_b_product_details
I'm guessing that they are probably si24R1's, even though the chip labeling in the photo says that they're nRF24L01's. I ordered some, and with the aid of the PPK2, I'll know soon just what they are.On Aliexpress they're even cheaper, but the wait is much, much longer: https://www.aliexpress.com/item/2251801699158809.html?spm=a2g0o.cart.0.0.202b38dax6gRtv&mp=1
They're so inexpensive that for short-range maybe they're good enough. I'm sure once the chip shortage is over that atmega328p's will be back to around $1 each. A $2 transceiver is pretty amazing. Like you say, the golden age.
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Judging from the "power enhanced" title in this listing: https://www.amazon.com/dp/B082VLQK1M?psc=1&ref=ppx_yo2ov_dt_b_product_details
I'm guessing that they are probably si24R1's, even though the chip labeling in the photo says that they're nRF24L01's. I ordered some, and with the aid of the PPK2, I'll know soon just what they are.On Aliexpress they're even cheaper, but the wait is much, much longer: https://www.aliexpress.com/item/2251801699158809.html?spm=a2g0o.cart.0.0.202b38dax6gRtv&mp=1
They're so inexpensive that for short-range maybe they're good enough. I'm sure once the chip shortage is over that atmega328p's will be back to around $1 each. A $2 transceiver is pretty amazing. Like you say, the golden age.
@NeverDie said in Most reliable "best" radio:
On Aliexpress they're even cheaper, but the wait is much, much longer: https://www.aliexpress.com/item/2251801699158809.html?spm=a2g0o.cart.0.0.202b38dax6gRtv&mp=1
At 10 for $5.30, I can wait. I just ordered some!
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@NeverDie said in Most reliable "best" radio:
On Aliexpress they're even cheaper, but the wait is much, much longer: https://www.aliexpress.com/item/2251801699158809.html?spm=a2g0o.cart.0.0.202b38dax6gRtv&mp=1
At 10 for $5.30, I can wait. I just ordered some!
@Larson What good luck: looks as though the pinout is an exact match for the pinout on my nRF24L01 adapter board for the test platform:
Makes me wonder what those two through-holes are for near the antenna?
Looks as though they are meant for something. Anybody know what those two through-holes are for? -
Ignoring the warning about not transmitting for longer than 4ms at a time, I'm presently trying to blast out a continuous stream of packets from the nRF24L01 at 2mbps datarate without pausing between packets. According to the datasheet, one way to do it would be to start sending the first packet while ensuring that the Tx FIFO never empties. However, none of the libraries seem configured for doing that, so it involves working with the nRF24L01 at a lower level. In the worst case, I guess I could settle for a 4ms long packet train if that's the best it can do, but maybe an nRF24L01 equipped with a TCXO could perhaps go longer than 4ms? The 4ms is evidently a PLL limitation, and I'm not sure exactly how the PLL interacts with the crystal, or whether or not a better crystal will lengthen the continuous transmit time.
Anyone here tried this before? I mean, come on, a lot of people here use the nRF24L01 as their go-to transceiver. Anyone? Anyone? Bueller? Anyone?
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@skywatch said in Most reliable "best" radio:
@NeverDie I suspect that in 'open loop' (i.e. no feedback as I understand that to mean) then frequency stability over a longer period might be questionable. So to be safe they recommend a limit across which frequency drift won't be noticable. But as always, I could be completely wrong!
That's what I was thinking also, but if that were the case, why would the 4ms limit apply only to Tx and not to Rx? I guess the only way to find out is to run it longer than recommended and see what happens. In the worst case I burn out a module, but they're so cheap it would be worth the sacrifice.
What's a bit weird is that it doesn't say anything beyond not keeping it on for more than 4ms. It doesn't indicate that it needs a rest period or anything, so, yeah, I'm guessing you're right: it's some kind of frequency stability thing that mysteriously applies to Tx and not to Rx for some reason.
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I went and did it. I got it to transmit continuously for many seconds before it peters out. And the packets it sends can be received, decoded, and understood. Exactly how long it goes seems to vary from one burst to the next, but a reset gets it going again. Anyhow, it works more than long enough for my purposes. :smile:
In case you're wondering why the current draw isn't higher (as it was in earlier pictures), it's because I turned the power all the way down to minimum, since I'm testing at close range. -
Also, I'm happy to confirm that the amazon smd nRF24L01 modules that I ordered (see earlier post) have a pinout that matches my nRF24L01 adapters. I've tried it out, and it works:
That said, what I received is a little bit different than what was pictured in the amazon listing. If you look at the through-holes that are near the antenna, one of them is much smaller on the modules that I received. It's much more like a via than a through-hole.
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Lastly, it sounds as though the shortage of legacy chips is going to continue for quite some time:
https://www.youtube.com/watch?v=YJrOuBkYCMQThe TL;DR is that there's little profit in those chips, and so there's no motivation for manufacturers to build expensive new plants to pump out yesterday's technology. I posted recently about the attiny3226, and now I wish I had bought some, because they're now all out of stock everywhere. I'm therefore debating whether to buy some attiny3224's, which lack as many pins, because they're presently in stock but soon will be sold out, jut like the attiny3226's. It might be years before things get back to normal.
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@Larson What good luck: looks as though the pinout is an exact match for the pinout on my nRF24L01 adapter board for the test platform:
Makes me wonder what those two through-holes are for near the antenna?
Looks as though they are meant for something. Anybody know what those two through-holes are for?@NeverDie said in Most reliable "best" radio:
Makes me wonder what those two through-holes are for near the antenna?
On ESP8266's, I wondered if the PCB antenna could be cut with a dremel tool and be fitted with an equivalent whip-wire. It would be cheap enough to try. It looks to be that the NRF24's are maybe making that easier? Again, cheap enough to try.
Thanks for all the updates to https://www.openhardware.io/user/310/projects/NeverDie#view=projects I've been busy updating all the files I've collected. You have been hard at work. All the added *.png and *jpg pictures really help. The *.rar files make it really easy to get into the guts of it all. I got KiCAD downloaded and am looking at the E28 project at the moment. Learning a new CAD tool will be a climb of its own for me.
For the benefit of others: To extract the *.rar in Windows 10, I downloaded a utility program (WinZip 21-day trial). Maybe everyone already knows that. What I have learned is that getting to the KiCAD files is a three step zip-sandwich procedure:
- download and unzip the openhardware *.zip file.
- find the *.rar file and use a utility like WinZip to unwrap it.
- unzip the resulting *.zip file.
The resulting four files (*.pcb, *.prl, *.pro, and *.sch) will deliver KiCAD access as a project via the *.pro file. It took me most of the day to learn that. There is probably an easier way.
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@NeverDie said in Most reliable "best" radio:
Makes me wonder what those two through-holes are for near the antenna?
On ESP8266's, I wondered if the PCB antenna could be cut with a dremel tool and be fitted with an equivalent whip-wire. It would be cheap enough to try. It looks to be that the NRF24's are maybe making that easier? Again, cheap enough to try.
Thanks for all the updates to https://www.openhardware.io/user/310/projects/NeverDie#view=projects I've been busy updating all the files I've collected. You have been hard at work. All the added *.png and *jpg pictures really help. The *.rar files make it really easy to get into the guts of it all. I got KiCAD downloaded and am looking at the E28 project at the moment. Learning a new CAD tool will be a climb of its own for me.
For the benefit of others: To extract the *.rar in Windows 10, I downloaded a utility program (WinZip 21-day trial). Maybe everyone already knows that. What I have learned is that getting to the KiCAD files is a three step zip-sandwich procedure:
- download and unzip the openhardware *.zip file.
- find the *.rar file and use a utility like WinZip to unwrap it.
- unzip the resulting *.zip file.
The resulting four files (*.pcb, *.prl, *.pro, and *.sch) will deliver KiCAD access as a project via the *.pro file. It took me most of the day to learn that. There is probably an easier way.
@Larson said in Most reliable "best" radio:
unzip the resulting *.zip file.
Uh, oh. As Bug's Bunnny would say, you may have made a wrong turn at Albuquerque, or, in this case, on step 3.
There is, I think, a much simpler way. Instead of manually unzipping the .zip file and trying to make sense of the contents, do this instead: in Kicad 6, under the "File..." menu, go to "Unarchive project...." and give it the intact .zip file. It will instantly recreate the entire project on the spot, exactly where I left off with it. It really couldn't be simpler. Try it. You'll like it.
Regardless, thanks for the feedback. I just now changed the instructions on the openhardware.io projects to make it more clear what to do.
