Lightning Detector Circuits | Hacker News Reader

Lightning Detector Circuits

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107 pointsnateb202244 comments

I was recently introduced to fully integrated lightning sensor ICs: https://www.digikey.com/en/product-highlight/a/ams/as3935-fr... - supply it a repurposed RFID coil and it will tell you when it detects lightning and how far the storm front is. I have one in my weather station just for fun, but it's a highly practical device for golf courses, swimming pools, sporting facilities, etc. where knowing how far away lightning is is operationally important.

I was considering one of these recently. By chance do you have any feedback on how well it works relative to the detection and the storm front tracking?

I hate these chips after a multi-year crusade to get one to work. I've bought 3 different variations of it on breakout boards (SparkFun, DFRobot, and another one off of Tindie) and spent 10s of hours fiddling with them trying to get them to work with no luck. That includes multiple attempts at tuning the antenna and calibrating the capacitance, tuning all the other detection parameters, multiple different microcontrollers, several different power supplies and physical arrangements etc in case of interference. Anything and everything I could think of and test.

Everything I did failed and I have never been able to get anything other than noise out of these sensors at best. YMMV, as I know these chips have a history of problems but supposedly do actually work. After I finally gave up on these things I ended up getting an Acurite 06045M, a cheapo SDR dongle, and a Pi Zero W running rtl_433 for like $60 and that has worked perfectly for years and is fairly straightforward to plug into Home Assistant over MQTT. It very reliably detects strikes and gives a pretty good estimate of distance (but NOT bearing), plus you get an outdoor temp/humidity sensor for free.

I think the 06045M might actually use the AS3935 internally so presumably you can get them to work and when they do work they work very well, but nothing I could do as a (pretty advanced and well-equipped) hobbyist could make them work, and I've heard others had similar issues with them. So maybe stick to buying something commercial with it inside?

Yes, that Acurite sensor and the one I have connected to my weather setup (Shenzhen Fine Offset / Ambient Weather) are all AS3935 based. I also have an Aliexpress "JMCU" AS3935 breakout/antenna board that I bought to play with after being pleased with the Ambient Weather sensor, and it seems to work OK to me as well - I had to tune the watchdog thresholds and gain to eliminate false positives, but after doing so it works great.

I did try tuning the watchdog thresholds/gain too but never had much luck. I read a few places that there might have been problems with some of the early AS3935 chips (but could never find too much info) and I know there were problems with some of the breakout boards on Aliexpress having the wrong capacitors on the board (which was another thing I tested/fixed). The one thing I never tried was all my boards are fairly old so they might have whatever the original hardware flaw is and maybe newer ones work as intended.

I've been mighty tempted to try again with a newer one as I really want to build a compact portable lightning sensor linked to Meshtastic but I dread going through the whole ordeal again.

Your trials around the AS3935 piqued my interest a little and I thought that maybe the Blitzortung/LightningMaps people may have tried working with them. It turns out they have! The earlier generation Red board documentation [1] has a section on them and there was apparently internal-to-operators discussion [2] which isn't directly public, but which points to wxforum.net where there were quite a few results with at least one [3] detailing struggles to get it working.

This probably isn't directly helpful but I found it a fun trail to follow for a bit.

[1] https://www.blitzortung.org/Documents/TOA_Blitzortung_RED.pd...

[2] https://forum.blitzortung.org/showthread.php?tid=1022

[3] https://www.wxforum.net/index.php?topic=22235.0

Thanks for that, many of the problems described there mirror my own experiences. Part of me really wants to take yet another stab at it with a newer board but I also am so burned out on it that it feels like borderline PTSD.

Hmmm so they're fiddly is what it comes down to. I was thinking of the one from Mikroe. The 06045M has the same 40km as that chip so I believe the other commentor that it's the same chip. Thanks

I get reliable detection out to about 25-30 km, but it depends on your placement and local RF environment. I hung my Acurite sensor on a nail up under a roof eave out of direct sunlight so as to get reasonably accurate air temperature readings and that seems to be pretty good for lightning as well. I'm in a bit of a valley which probably limits my range somewhat, I am fairly confident the 40 km range is possible with the right placement.

Good to know, thank you

Here is a board ready to use:

https://www.sparkfun.com/sparkfun-lightning-detector-as3935....

I was heavily involved with the local soccer community, and as a coach/referee I carried my own detector that I paid less for a ready to go version than this DIY shield. I was not going to depend on someone else's gear functioning when these were so cheap.

Got a link to that detector? The cheapest self-contained lightning sensor in a portable form factor I know of nowadays is the Acurite 02020 and it's around ~$50 nowadays.

That's interesting. That's the same one I have, but I only paid $27.99 for it. I couldn't remember what the model was, but Amazon shows that I purchased that model and clicking the View Order link it shows $27.99. I guess I bought at the right time??? Maybe it's tariffed to death?

https://camelcamelcamel.com/product/B00EO1H3X8

Looks like it's steadily increased, labor maybe? Just a WAG on my part to be sure, I'm too far away to legitimately speculate.

likely the chip in it is out of production

lots of products like this are increasing because nobody is running the older cheaper fabs

I'm interested in this type of device in a boating situation. The network based systems wouldn't work for me.

Can somebody provide clarity on if any of the boards really work?

It seems that bri3d has faith in the ScioSense.

They do but without information from additional locations all you can get is distance and sometimes direction (dependent on specific chip / circuit). The ones with direction will probably good enough for most boating awareness situations.

If you want to know more specifically you need to have separate sensors that have with reasonably synchronized clocks so they can trilaterate or triangulate strike locations. Those sensors probably need to be further away from each other than most boats allow for. The further away the sensors are from each other, the tighter the time synchronization between them, and the more sensors you have will determine the overall accuracy your system will be able to attain.

> so they can trilaterate or triangulate strike locations

I don't think that's feasible. These sensors work by detecting radio waves which propagate near the speed of light. Even if you had two sensors separated by 1 km, they'd both receive the radio signal within ~3 µs of each other. I don't think the sensors guarantee detection time to that level of precision, nor that it's feasible to keep clocks sufficiently synchronized that you can timestamp events at a sub-microsecond level.

You're partially right for the case of trilateration, usually these would be placed about 10km apart with a GPS PPS clock (at least) and would be using sensors with a much faster response rate.

With triangulation you only need the clocks accurate enough to correlate the events. This will largely be determined by the rate you see events, and you only need to distinguish specific events if you want to differentiate locations of individual strikes as opposed to a storm front. For a boating case you probably only care about the location of a storm front.

Two sensors measuring angles from a couple dozen meters apart can get you a pretty precise location of storm front especially when aggregating results from multiple detections.

It's quite feasible. There are a few approaches. It's common to build lightning detectors with four antennas in a square, which gets you a rough vector to the s strike. That's 1950s ham radio technology.

Synchronizing multiple receivers is common. That's how passive ADS-B locators work.[1][2] This works so well there have been attempts to stamp it out.

[1] https://www.adsbexchange.com/what-is-the-exchange/

[2] https://adsbglobal.com/

Thanks all. I will look into the square configuration but I also have doppler RADAR direction might not be as crucial as knowing that static charge is building up.

Better yet, this network

https://www.lightningmaps.org/#m=ses;t=3;s=0;o=0;b=;ts=0;

triangulates lightning strikes detected by this method. Right now I see a front moving between the Triple Cities area and Scranton.

Real time, community sourced lightning map: https://www.blitzortung.org/

Posted this some time ago, but it got no traction :(

Well. I bookmarked it now. Seems to have got an update, since the last time I looked at it. Meaning it just works. But not necessarily better than the lighntingmaps.org I've used instead. Different styles for the same thing. Will check in the future from Hamburg, .de and Aspen, CO how accurate it really is.

My understanding is that lightningmaps.org is owned/operated by Blitzortung (see the upper right corner of lightningmaps.org).

Could be, I seem to recall some relationship. It was just that blitzortung didn't work right for me. While lightningmaps did. Anyways. That's from years (maybe 10?) ago.

Maybe my browser just got better? Who knows :-)

By working right, I mean whenever I see flickering from afar, or hearing the first rolling of thunder, clicking on it without much fuss, maybe zooming out, shifting a little, zooming back in and seeing what's going on where instantly.

Which in the context of larger storms works even better in kachelmannwetter.com, because there it's embedded in other data, and projected where it moves/arrives in how many minutes in easily understandable symbology. But that's for Germany only. Useless for Colorado. Havn't found something comparable for there, so far. Would be mostly useless anyways, because weather at 2600+ m altitude changes faster. Or can.

On one hand I really like that project and what they do, but on the other hand I hate how it's managed.

I was very excited about it over ten years ago and wanted to join the network. They are very weird about not releasing the designs and code, and instead want you to get it from them. Fair enough, but then they don't produce and ship units. I signed up for a waiting list like 10 years ago, with many others. They kept promising a new design, but never delivered it, and didn't let anyone else do so. I never heard back from them about the waiting list.

They are also restrictive about access to the data if you are not in the network, with reasons like it's too expensive. That might have been true 10-15 years ago, but today it's just silly.

It's a shame, I think there is lot of potential to make a better community and more usable free apps around this data. But you would have to start a new network from scratch because these people are not interested in that.

It's been around long enough that I think it's pretty well known by now. At any rate, it was posted 11 months ago by someone else and has a number of comments: https://news.ycombinator.com/item?id=41370187

I just learned about it today. https://xkcd.com/1053/

I remember seeing an overly simplified lightning detector presented in a book: just an antenna, Neon bulb and a ground wire. I thought it was too simple to work.

Here it is discussed though by someone who tried it (and improved it):

https://www.angelfire.com/oh3/ebjoew/Charged_Cloud_Alert.htm...

(Ha ha, angelfire)

Makes me think of the World Wide Lightning Location Network

> We welcome offers of hosting a new WWLLN lightning sensor. All hosts receive all the world-wide data for their own research.

https://wwlln.net/#home

I spent a LOT of time on this website as a 90's kid. One of many that inspired me to get an EE degree. Projects like this always felt like some incredible magic, and came with an artistic aesthetic that I find inescapably captivating. We've instead got little bits of black epoxy everywhere these days and it's just not the same!

Perhaps this and more. :)

https://www.blitzortung.org/en/whats_new.php https://www.blitzortung.org/en/cover_your_area.php https://forum.blitzortung.org/forumdisplay.php?fid=30

Skip the perfboard with nails and you would have had an actual breadboard... What a weird prototyping approach... Nails in a perfboard... Never seen it before.

Honestly I really like the low tech steampunk? kind of vibe of nails in a board.

It really does nail that aesthetic!

I have plenty of PoCs that were built from whatever lumber I happened to have available. It's much faster than waiting for something to 3D print. A DIYer's garage without scraps of various cuts of lumber is just broken.

Its an interesting take on old-school point-to-point wiring using turrets:

https://en.wikipedia.org/wiki/Point-to-point_construction

https://entertaininghacks.wordpress.com/2020/07/22/prototypi...

I assume the author liked the idea and used the perfbaord/punchboard as a grid.

Love to hear ideas on what you'd wire this up to - eg. What kind of device or process do you want to trigger once lightning is detected?

Usually, lightning detection is necessary for regulatory compliance. Facilities with pools need to remove patrons to prevent risk of electrocution, summer camps need to move people to enclosed shelters, as with golf courses, construction sites, beaches/waterfronts, etc.

A camera! The 2.5mm TRS remote trigger jack just needs one of the pins connected to the sleeve to trigger the camera, very easy to do with an optocoupler or even relay.

I have a lightning detector hooked up to Home Assistant. It plays a little sound on a buzzer if there are more than a handful of strikes. It's a pretty reliable warning a storm is coming, and my partner (who is a prolific runner) knows not to go out for a run or to turn around.

I've also done sciencey type testing work outdoors, the ranges all had lightning detectors and all work would stop and you had to take shelter if lightning was detected. Mostly wide open space so getting struck by lightning was a serious danger.

> Watch out; there's a smaller, identical-looking bolt just a few inches tall

Pahaha pure Spinal Tap moment

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