Friendship ended with LoRa, now 2-FSK is my best friend
This is mostly a venting post, it’s not going to be especially coherent but it feels important to write. As a bit of background, LoRa is a marketing term created by Semtech for a proprietary chirp spread spectrum modulation scheme that they use in some of their radio transceivers. It ostensibly stands for “low-power long-range” and I will concede that their receivers have impressive sensitivity ratings. But at a very steep cost. Active receive current draw is around 10mA and there’s no low-duty-cycle mode or really any other mode you can use to reduce that. That’s such a bummer to me. A cellular radio can maintain an association with a tower in eDRX mode drawing under a milliamp on average. Meanwhile, the “low-power” alternative to cellular draws 10x that current and is hailed as revolutionary.
What’s especially frustrating is that there are actual low-power ISM transceivers out there. Notably, the STMicro S2-LP draws around 21 microamps on average in low-duty-cycle receive at 1200 baud (not a typo, nearly 500x less power draw than LoRa).
There’s not really much more to this post than that. LoRa is not low power. It’s impressive for other reasons:
Good marketing.
Good link budget.
Extremely approachable for hobbyist use.
That last point is not to be underestimated. I’m working on making the S2-LP a little bit more approachable for hobbyists as a part of one of my current projects. I’d like to get to the point where there are $2 counterfeits of my hardware on AliExpress and a vibrant community of makers building cool stuff with it, with 500x lower power draw than LoRa modules. :)