How to find the DevEUI on a RFM95

[johan (Johan Stokking)]

@descartes

I had a hiccup getting my auntie’s LMiC Adafruit Feather RFM95 with all zeros - no worky.

It’s valid LoRaWAN, but indeed I can imagine some lightweight end device libraries don’t see a difference between zeros and “not set”.

@bluejedi

Mmm, I guess that getting a valid DevEUI is what most users were expecting (for years already) when they request the V2 Console to generate a DevEUI for their device.

Makes sense. Issue is filed, you can subscribe here: Issue DevEUI from range with maximum per application · Issue #3750 · TheThingsNetwork/lorawan-stack · GitHub

@bluejedi

Aha! Well, at least we can blame The Things Network for applying that bad practice.

Not really though, because in The Things Network V2 and V3, only the combination of AppEUI/JoinEUI and DevEUI is unique. Since V2 did issue a globally AppEUI to each application, it didn’t really matter what the DevEUI is. With V3, since we don’t issue an AppEUI/JoinEUI, so then it does matter what the DevEUI is, and it shouldn’t be random.

@kersing

I would suggest a maximum per user. If a user needs a lot of them they can buy their own MAC-S

Agreed, but in the context of applications we don’t have users, only a bunch of collaborators, and keeping maxes across all of them is not feasible.

@bluejedi

The EEPROM costs around € 0,40 (in low volumes) and that includes the hardware so the EUI-64 should only be a fraction of that price.

It’s really cheap indeed. 28 degrees of freedom costs USD 780, so roughly 0,000003 cts per DevEUI. And it gets much cheaper in volume, like the OUI / MAC-L blocks that most vendors have.