A personal lightning strike detector and dangerous weather alerting device

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An estimated 6000 to 24000 people are killed annually due to lightning strikes. In the US, the most fatalities occur while fishing, camping, and boating. What if you had a device to warn you about nearby lightning and storm activity?

This project pairs a realtime lightning strike detector, the AS3935, which has a sensing range of 40km, through a LightBlue Bean to your cell phone for getting an accurate lat/long position. It queries a WeatherUnderground API to get local conditions and parses the results for storm alerts. Either detected lightning or new weather alerts will light an LED and play an audible or haptic alert on the phone to warn the user to seek lower ground and shelter.

This was a project idea I came up with for a recent Hackathon in Portland, but for that event we were given Intel Edisons to develop with. While the core Edison is quite small, the prototyping board for it was huge, far too large for a personal device, but adequate for proving the concept worked and could be built. This is version 2.0 of that idea but using a LightBlue Bean as the device, which is much smaller, has its own battery and bluetooth, and can interface directly to the lightning sensor.

The Lightblue Bean offers a number of useful features that will made the second generation of this idea even more sophisticated than the original idea (which we prototyped with an Intel Edison and development board).

Since the Bean has BLE bluetooth native to the device, it can easily interface with the phone (Android or IOS) and query the weather API with current Lat/Long coordinates to screen it for any current or predicted weather issues that the user would want to know about.

The accelerometer can be used to conserve battery life since if the device (and the person holding/wearing it) isn't moving, we don't need to re-acquire GPS location.

The small size of the Bean is also much more conducive to a small wearable that can be carried as a pendant or a device clipped to a belt, pocket, or strap.

Another feature that we didn't have time to implement during the frantic Hackathon that I am looking forward to completing is to leverage this as a "mesh" alert system. The lightning sensor being used here can detect lightning arcs or strikes up to about 40 km away. But since we have access to the latitude and longitude of each device, and can upload strike information to the cloud (pun intended), we can provide extended alert coverage to other users outside of their 40km range. It's a simple calculation to determine the distance between devices and remotely notify a user if another device in say an 80 to 100 km perimeter detected a lightning strike. Given than a single bolt of lightning can travel up to 25-40 km from its origin, extending that umbrella of warning by using shared (but anonymous) data will be a huge help.

  • delays but new component

    brian bloom06/29/2015 at 15:35 1 comment

    I haven't had the time to do as much work on this project as I wanted due to a number of causes: end of the school year for my daughter, I've built a new workbench and my office is a mess while I move it in, and I got a new computer and it's taken some time to get all my software installed on it.

    The other news though is that I got a new lightning sensor chip to play with! This one is from Embedded Adventures in the UK. It looks somewhat like the PlayingwithFusion one I'd been using, but this one supports I2C as default and has a newer design (a 6th revision updated as of April as opposed to the indeterminate version in the PWF device)

    I'll need to update my schematics to reflect this new device now. Hope I'm still a candidate for Hackaday prizes though. :)

  • Not grokking Fusion 360

    brian bloom05/20/2015 at 22:00 0 comments

    Okay Fusion 360 doesn't like me. I'm going to have to spend some time learning this app before I can make any actual progress. I tried out some of the other options (FreeCad, 123D, DesignSpark Mechanical, etc) but none of them could open the Inventor IPT file format, and the STL file is already a mesh, so hard to stretch it and keep the lines straight. And anything else (that might import an IPT) appears to cost money, so I guess I need to keep trying to figure out Fusion 360. Boy I wish I could reassign these mouse buttons...

  • Designing the enclosure

    brian bloom05/19/2015 at 17:28 0 comments

    First off, I received the LightBlue Bean from Hackaday's weekly prize giveaway so a big thanks for that! I'm continuing with the design of seeing if I can mesh it with the lightning sensor.

    So I've started working on an enclosure that will hold the LightBlue Bean plus the lightning sensor breakout board. I found a really great starting point on Thingiverse by Jwags55 that holds the LightBlue Bean plus has room for other components:

    I'm working (well, trying to work) with Autodesk Fusion 360 to modify the starting design to accommodate the width of the breakout (it's a rectangle about 2.4 x 2.6 cm), so it's a bit wider than the LBB (which is a svelte 2.1 cm wide). Sadly however, my Fusion 360 skills are not yet up to snuff at reshaping that part. I was at least able to remove one of the tabs, and increase the hole size in the other one so that it can be clipped to a keychain or lanyard.

    Here's where the progress is so far (still very much a work in progress):

    Now I apparently need to figure out how to convert the "model" to a "mesh" so I can use the sculpt tools and pull the sides of the blue part wider (without changing the lip size, if possible). I may try using another CAD/modelling tool as Fusion 360 isn't as intuitive as I'd like (and I've used other 2D CAD tools in the past, plus years of Photoshop experience, but I'm still struggling with this one)

    I think I'll also try to raise the lanyard tab so it's closer to the center of gravity of the combined case. The original design was meant to be screwed onto a surface, not worn hanging. The current design I screenshot (screenshotted?) above would hang kinda lopsided.

    Since I don't own a 3D printer (not yet, anyway, but eventually I hope to) I'm hoping to also score some of that Shapeways gift credit that I could use to start prototyping the enclosure designs with.

  • LightningBlue Bean?

    brian bloom05/01/2015 at 01:23 0 comments

    I've prototyped using Fritzing how The LightBlueBean should connect to the AS3935. If the Bean can't supply sufficient current from VCC, I'll add a LiPo battery to the mix with a regulator to power both devices.

  • Ready to get beaned!

    brian bloom04/30/2015 at 23:16 0 comments

    I successfully prototyped this project (as a standalone device without the Weather API) using an Arduino and the AS3935 detector. That circuit is shown as the main picture for this project and could be triggered reliably using an artificial lightning source - the sparker from a BBQ lighter.

    Now I'm ready to make it portable using a more appropriate device that can be worn out in the field and communicate with a cell phone.

    What I'd like help with from the Hackaday folks is the chance to win one of those LightBlue Beans with Bluetooth LE so that I can redo the circuit in a small form factor and interface with a phone to provide information to the user about how far a lightning strike was detected (the AS3925 can be queried over SPI to report the estimated distance away) plus any weather alerts from the Weather Underground API.

    The Bean is ideal from a size and power perspective. It also pairs well with the AS3935 breakout board which can use the 3V power like the Bean plus has SPI and I2C and the ability to register a hardware interrupt, which is how the AS3935 responds to detected lightning.

    So, can you guys hook me up with one so I can move forward with the new and improved reboot of the StormSafe lightning and weather alert device?

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C. Prichard wrote 05/20/2015 at 22:43 point

I checked the website,, nice way to protect my OFF-GRID inverter when running 24/7 for refrigeration.

  Are you sure? yes | no

Nick van de Giesen wrote 05/17/2015 at 16:33 point

Hello Brian: We ( are working wth the same lightning sensor. The exact algorithm it uses is a bit vague. They store information for individual strikes but it is not clear what this is, exactly. I have asked the manufacturer but they declined to share that information. They then use a statistical approach to determine the front of the storm, which is then reported... I am curious to hear/see how you get along with this all and it may be good to stay in touch. Gilbert Mwangi has used them to locate strikes with fixed stations so your idea to do the same with moving "stations" should work and could be a very interesting service to set up! - Nick

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brian bloom wrote 05/18/2015 at 18:32 point

My handicap is that I live in Portland, which while famous for rain actually gets very little in the way of lightning.  So I don't have a very good testing grounds for experimenting with accuracy or methodology.  But I at least wanted to see if I could do the full circle of direct lightning connection meets networked weather and other stormsafe triggers.

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Nick van de Giesen wrote 05/19/2015 at 02:12 point

If you have anything you want tested by 1st week of July, I will be visiting Rwanda then and meet up with a scientists who will install weather stations in eastern DRC, the lightning "capital" of the world:

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brian bloom wrote 05/05/2015 at 15:16 point

The breakout board I'm using a has a small antenna on it, and lightning puts out some pretty significant electromagnetic bursts.  The maker of the chip doesn't elaborate on the specific mechanism for measuring the lightning, just divulging the following:

"Utilizing a sensitive RF receiver and integrated proprietary algorithm, the Franklin Lightning Sensor™ detects the electrical emissions from lightning activity and then provides for an estimation of the distance to the head of the storm from 40km away down to 1km, while rejecting disturbances from man-made signals such as motors and microwave ovens"

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Dylan Bleier wrote 05/05/2015 at 00:50 point

I'd like to know how the AS3935 has a 40 km range.....  is it more than just a radio reciever?

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