[Feature Request]: Support for AS3935 sensors (lightning detection)

[lukekoch]

Platform

Cross-Platform

Description

The AS3935 is a sensor for the detection of weather lightning events through the electromagnetic effects of a lightning strike with a range of up to 40km (according to the manufacturer). I2C-capable boards with low power consumption are available from multiple large DIY suppliers. I believe the sensor would be a great addition for meshtastic, allowing users to monitor severe weather conditions remotely and off-grid. The high-up placement of nodes also makes them excellent at receiving signals from lightning strikes.

[github-actions]

@lukekoch, Welcome to Meshtastic! 👋

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[caveman99]

@oscgonfer love to hear your opinion on this sensor type. Especially considering we can not trigger a packet everytime lightning is sensed.

[oscgonfer]

Thanks for the ping @caveman99. This sensor has been in my radar for a while and wanting to find an excuse for testing it...

Since the sensor is not "on demand" as we are used to for most sensors (as far as I know) EDIT: except for detection module, I assume we'd need to trigger an I2C read for lighting / storm distance data after the detection event, but I think we can't (yet) trigger readings on demand by GPIO pins (I am not so familiar with how the detection module is currently implemented, but having taken a quick look, it seems that we only detect events). This would need to be factored in and consider maybe a new sensor type (on demand), or similar?

The sensor also seems to have specific timings that need to be accounted for (after detecting a lighting it seems?). Combined, I am not sure if it's best to integrate this on the main firmware, or on a surrogate MCU that can exchange data with supported meshtastic MCUs...

Besides that, the desired packet structure for this in telemetry module would probably match future plans (instead of a single reading every time), given the nature of "master"/"bossy" sensor this is. I would suggest having a history / aggregation of events together with some additional metrics (# of lighting in the past X reading interval, minimum distance to storm detected, etc.) that gets delivered instead of a single measurement. This would potentially be aligned with the (hopefully, but yet to be agreed upon) short-medium term plans in Telemetry and its potential Database/new packet structure with history of readings.

[ndoo]

@lukekoch @oscgonfer we are entering monsoon season here in West Malaysia and so lightning detection is a looming concern for us.

I used CC to generate what the feature could look like.

• Firmware: Add AS3935 lightning sensor support #10931
• Protobufs: Add AS3935 lightning sensor telemetry fields protobufs#981

For your consideration + cc @caveman99