Most reliable "best" radio

[NeverDie]

@Larson Will a firecracker actually kill a mole? This guy shows off his simple contraption that uses 500v to instantly kill rodents:
https://www.youtube.com/watch?v=-xkOtVlDUbw

The key seems to be charging high voltage capacitors, so that enough current is released at 500v when triggered. I know: dangerous as hell, but maybe this is where your wireless human-in-the-loop firing trigger could come into play so that it doesn't kill anything that it's not supposed to.

He says it's highly effective.

I don't know whether something like that would work for moles or not. I guess it depends on whether they ever leave their holes to look for food or whether they stay underground all the time.

I wouldn't feel comfortable walking up to something charged to 500v, but maybe that's where radio electronics could completely disarm it down to zero volts when commanded before you even think of touching it. His is more basic and doesn't have that added feature. I would want redundant everything on the safety features so that there's no chance of it going wrong.

As for charging it up, I think one of these would work for fairly cheap:
https://www.amazon.com/gp/product/B07JG4K6S6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
as long as you terminate the charge when it gets to 500v and not let it continue on to 15,000 volts, which would destroy your charge capacitor. Since it comes in a pack of two, maybe the other one could be used to energize an electric fence? I know nothing about electric fences or what voltage they use, but I would hazard a guess that the circuitry is similar (flyback transformer design), and then all you would need is the right kind of wire and some insulated stakes.

An electric fence is an interesting idea, provided it doesn't ignite dead leaves and create a fire. Not sure whether or not that's even a risk. I presume that professional electric fences wouldn't do that.

[skywatch]

@Larson Do you have any links to this please? I found next doors 2 new cats killing 2 young birds they had paicked out of the tree and onto my lawn. The owners are un-cooperative on the issue and the cats have been using my garden as their own litter tray..... Garlic, chilli powder and vinegar have had no effect so I need to up the game!

[NeverDie]

@skywatch We had a neighbor with a cat like that once. Same liter box behavior as what you describe. I was sooooo glad when they finally moved to somewhere far away.

[Larson]

@NeverDie said in Most reliable "best" radio:

Will a firecracker actually kill a mole?

I'm not sure. But the MoleCat100 uses the blast from a 22 blank, and that has to be close to the concussive force of a firecracker. Being under the dirt by about 4" has to also help in rendering an effective shock wave since dirt is far less compressible than air.

@NeverDie said in Most reliable "best" radio:

The key seems to be charging high voltage capacitors, so that enough current is released at 500v when triggered.

Smoking Cool, and yea, probably dangerous. I was playing with flash bulb circuits from disposable cameras as a potential igniter. I accidently shorted a loaded circuit, and the thing burned a hole in my screw driver. Stunned and temporarily blinded, I put it away immediately and haven't gone back since. I don't think the 500 V device would work on moles; they do their foraging in their tunnels. Probably grubs and worms. Maybe they come out at night?

MouseTrapMonday has probably featured this 500 V device. He has quite a collection.

The Comidox 15KV looks like fun, and again dangerous. Glad to see that the thing comes disassembled. Assembly provides some knowledge requirement at least.

My electric fence is this one. It seems to have internal circuitry that limits grounding problems. The thing sends pulses at about 1Hz. Using a blade of grass, or green straw one can feel the pulses. I've had branches fall on the fence and pin it to the ground without resulting in problems so far. It would be fun to do a tear-down to learn how they work... but I've got these radios to play with.

[Larson]

@skywatch said in Most reliable "best" radio:

Do you have any links to this please?

Sure, Here it is on Amazon. I got mine at Coastal Farm and Ranch. While I'm now using it for skunks and racoons, I initially used it on the swim platform of my old wooden boat that was a party scene for sea otters. They can really stink up the boat after a winter.

[NeverDie]

@Larson Since it's fed by AC from the wall, I'm guessing it's a relatively straight forward transformer based design rather than a flyback circuit, but I'm no expert in such things. I presume there's some kind of circuit in addition which renders it safe and non-lethal. Probably best to go with something known to work safely like that for an electric fence and not go the flyback transformer route, especially since the price is so low to begin with.

[Larson]

@NeverDie I wouldn't know as I haven't studied power supplies outside of the engineering fundaments, yet. There is a version of these fences that use car batteries & solar charging. So they probably use different transformers.

I sure hope we didn't stink-up your thread with all this rodent-talk.

[NeverDie]

@Larson said in Most reliable "best" radio:

I sure hope we didn't stink-up your thread with all this rodent-talk

No worries. I'm not a stickler for staying on topic. I always say go where the interest is.

[NeverDie]

@Larson said in Most reliable "best" radio:

MouseTrapMonday has probably featured this 500 V device. He has quite a collection.

He's the one who demonstrated the dead fall skunk killer. He's also demoed some no-spray catch-and-release traps, but I don't see those as practical for anyone but the pro's. The way they work is interesting though: supposedly a skunk has to be able to raise its tail to spray, and the no-spray traps don't give them enough room to do that. The downside is that once you release a skunk from the no-kill trap, it can raise its tail and spray you, which is what happened to him in one of his videos.

[Larson]

@NeverDie Hilarious.

Release problem: Nothing that a remote, a servo, a relay, and a radio couldn't solve. All of which would get sprayed anyway. Hmmm...

[Larson]

@Larson said in Most reliable "best" radio:

Hilarious

Uh... after finding and watching the dead fall video, I downgrade my "Hilarious" comment to "Interesting". Back to the joy of radios!

[NeverDie]

@Larson said in Most reliable "best" radio:

@Larson said in Most reliable "best" radio:

Hilarious

Uh... after finding and watching the dead fall video, I downgrade my "Hilarious" comment to "Interesting". Back to the joy of radios!

I know what you mean. Not sure why, but even if the crush physics are equivalent, somehow his design does seem more disturbing than having a giant falling bolder do the dirty work. On the other hand, at some level it's no worse than road kill, which happens all the time, and most people seem relatively dismissive about that.

In any case, thanks for your post and info regarding the electric fence.

[NeverDie]

As a first pass I tried running the RadiolLlb on these two 20dBm nRF24L01's with the default settings:

and although they work fine at closer ranges, they delivered zero packets (i.e. total fail) along my worst-case transmission path. Make of that what you will. I'll see if I can possibly tweak some settings for a better result and then re-test, but those are the early results. I thought them worth testing because many people here like the nRF24L01 radios and because those radios do have good support for over-the-air updates on the atmega328p.

To be fair, there do exist some nRF24L01 modules on Aliexpress with even higher transmission power, so maybe a pair of those would cut the mustard.

I purchased them on amazon, mainly because I could receive them a lot faster than ordering something from China: https://www.amazon.com/dp/B07QC1SXJ8?psc=1&ref=ppx_yo2ov_dt_b_product_details

[Edit: same results even if I reduce the datarate to 250kbps. ]

Well, too bad. They do work for short range. Although this isn't rigorous testing by any means, I'm concluding that long-range for the nRF24L01, or other impairments, is essentially out of consideration Its niche is short-range, and for non-amplified versions preferably line-of-sight short-range. Sorry if that seems harsh, but for a comparison of different radio modules, somebody has to call it--and that's how I'm calling it. If somebody has a better nRF24L01 module that they feel would test better, please make a post and let us know what it is.

[NeverDie]

Surprise! I'm getting it the nRF24L01 modules to send and receive, even along my worst-case transmission path, though for some reason ack's aren't being received along that worst-case path. Not sure why there would be an asymetry like that. Apparently the RadioLib library didn't default to full transmission power, because when I set transmit power to 0dB (which gets amplified by the PA), I'm now getting great radio communication. And this is the 2.4Ghz band, no less. Who would have thought? I'm flabbergasted. If anyone wants to replicate, I've posted my modified RadioLib sketches to source-code tab of the openhardware.io project for the nRF24L01 adapter.

Even if I increase the datarate to 1mbps, the majority of the packets are still getting through. This may turn out to be a closer horserace than I had originally thought: it may yet require some careful measruements to separate out the winner.

[Edit: As a result, I just now ordered some of these E01-2G4M27D: https://www.aliexpress.com/item/3256801616913450.html?spm=a2g0o.order_list.0.0.24f21802jP9dtI
presently on sale for $4.34 each with free shipping, which allegedly contain TCXO's and, hopefully, should be a further step-up in performance. In fact, these may be the top-end of what's currently available on the market in the nRF24L01 series.

Now the long wait for them to arrive....]

[Larson]

@NeverDie said in Most reliable "best" radio:

If anyone wants to replicate, I've posted my modified RadioLib sketches to source-code tab of the openhardware.io project for the nRF24L01 adapter.

That is my aim (to replicate). I've got these radios on order, but from China.

@NeverDie said in Most reliable "best" radio:

Not sure why there would be an asymetry like that.

I'm thinking... maybe because of the compounded probability of the second (ack) transmission? Maybe having a secondary transmision counter for the ack would help? I'll play with it if I'm not too late. As said, you move fast.

[Larson]

@NeverDie One other late thought is to have some standard of antennae selection. I was thinking to make the different radios comparable some limit would be needed, I was thinking I'd stick to the bare 1/4 WL wire. But, reality of antenna science is probably far more complex. Thoughts?

[NeverDie]

@Larson said in Most reliable "best" radio:

That is my aim (to replicate).

Great! When you do, be aware that I found a bug in the RadioLib library wrt the nRF24L01, but it's easily patched: replace micros() with millis() in this section of their library code:

int16_t nRF24::receive(uint8_t* data, size_t len) {
  // start reception
  int16_t state = startReceive();
  RADIOLIB_ASSERT(state);

  // wait for Rx_DataReady or timeout
  //uint32_t start = _mod->micros();
  uint32_t start; 
  start = millis();
  while(_mod->digitalRead(_mod->getIrq())) {
    _mod->yield();

    // check timeout: 15 retries * 4ms (max Tx time as per datasheet)
    //if(_mod->micros() - start >= 60000) {
    if((millis() - start) >= 60000) {
      standby();
      clearIRQ();
      return(RADIOLIB_ERR_RX_TIMEOUT);
    }
  }

I commented out their erroneous code and put my corrected code beneath it. Doing this will allow the radio to listen in Rx mode for a minute before timing out. If you don't make the change, it will time out after 60ms, which I can't imagine is what they intended.

Of course, you may choose to use/try a different nRF24L01 library entirely. There are plenty to chose from.

[NeverDie]

@Larson said in Most reliable "best" radio:

I'll play with it if I'm not too late

I imagine you'll have plenty of time. I'll try again when the E01-2G4M27D's (see edited comment above) arrive, but unfortunately those may not arrive until the end of July according to aliexpress.

[NeverDie]

@Larson said in Most reliable "best" radio:

@NeverDie One other late thought is to have some standard of antennae selection. I was thinking to make the different radios comparable some limit would be needed, I was thinking I'd stick to the bare 1/4 WL wire. But, reality of antenna science is probably far more complex. Thoughts?

You raise a good point. Not really sure. I'll have to marinate on that one. For better or worse, some modules more or less force the use of different antennas than just a wire-whip or spring, because they come equipped with SMA connectors or u.fl connectors or they have trace antennas. As near as I can tell, dipole antennas are generally the best overall, unless you're deliberately trying to do something directional. So, one could maybe argue that we should test with dipole antennas, although that's easier said than done because it's easier with some modules than others.

I started this radio testing with the expectation that one radio, or at least one type of radio, would stand head-and-shoulders above the rest, regardless of antenna type. However, maybe that won't turn out to be the case, which will in itself be be an interesting result if that's how it plays out. For instance, by picking the E01-2G4M27D to test with, I'm certainly giving the nRF24L01 far more advantage than it ever would have if I were using just regular dirt cheap nRF24L01 modules without any PA or LNA. Those by themselves would have no chance of competing, except at very short range. However, for very short range applications, they may very well be winners because of their 2mbps data rate.

[Larson]

@NeverDie said in Most reliable "best" radio:

Of course, you may choose to use/try a different nRF24L01 library entirely. There are plenty to chose from.

As I say to my physician, dentist, and probably my mother: you lead, and I will follow. Your library is my library.