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
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