4 ms·

Yeah, I did this myself not long ago as part of a mobile office rig and ... I didn't write about it or share about it becuase it was mostly just putting USB mal

Yeah, I did this myself not long ago as part of a mobile office rig and ... I didn't write about it or share about it becuase it was mostly just putting USB male connectors into USB female connectors and sourcing the right kind of batteries to charge things. Oh, and learning ethernet cables are a monstrous power draw and you're much better off using wifi for everything. I mean, yeah it's cool to have. But I can't help but feel like it's a bit trivial.

Mary-Jane 7y ago
Everyone's gotta start somewhere.
- KirinDave 7y ago
  True. I confess I screwed up on the battery choices more times than I care to admit.
voltagex_ 7y ago
Can you comment on Ethernet being more power hungry than Wifi? That's the first time I've heard that.
- eigenloss 7y ago
  Ethernet usually requires isolation magnetics and transformers, while WiFi is basically just a wire sticking out of an RFIC.
  - pjc50 7y ago
    It's not so much that the transformers consume more power than just radiating it into the air, but that Ethernet is not designed with power efficiency as a goal. Ethernet devices that need more power usually get it from PoE instead. Without doing any analysis at all, I suspect the idle behaviour is a big difference; Wifi goes silent if there's no traffic, apart from AP beacons, but Ethernet continuously transmits "fast link pulses" every 16 miliseconds to maintain autonegotiation and detect connection lost.
    - KirinDave 7y ago
      Honestly I dunno why it was the case for me. What I know is that I thought I'd save power pushing pulses over copper rather than using a radio. I didn't. In fact it was consistently about 40% worse than wifi. That might be unique to the RPi hardware I used. It might not. Maybe I should have written that article. :)
      - londons_explore 7y ago
        The Pi does Ethernet with a seperate and pretty power hungry chip. If the ethernet cable is disconnected, that chip mostly powers down. I think it's a Pi related thing rather than being inherent to Ethernet. In fact, if I were to guess, the energy per bit per meter of ethernet is probably far far lower than WiFi.

Mary-Jane 7y ago

Everyone's gotta start somewhere.

KirinDave 7y ago
True. I confess I screwed up on the battery choices more times than I care to admit.

voltagex_ 7y ago

Can you comment on Ethernet being more power hungry than Wifi? That's the first time I've heard that.

eigenloss 7y ago
Ethernet usually requires isolation magnetics and transformers, while WiFi is basically just a wire sticking out of an RFIC.
- pjc50 7y ago
  It's not so much that the transformers consume more power than just radiating it into the air, but that Ethernet is not designed with power efficiency as a goal. Ethernet devices that need more power usually get it from PoE instead. Without doing any analysis at all, I suspect the idle behaviour is a big difference; Wifi goes silent if there's no traffic, apart from AP beacons, but Ethernet continuously transmits "fast link pulses" every 16 miliseconds to maintain autonegotiation and detect connection lost.
  - KirinDave 7y ago
    Honestly I dunno why it was the case for me. What I know is that I thought I'd save power pushing pulses over copper rather than using a radio. I didn't. In fact it was consistently about 40% worse than wifi. That might be unique to the RPi hardware I used. It might not. Maybe I should have written that article. :)
    - londons_explore 7y ago
      The Pi does Ethernet with a seperate and pretty power hungry chip. If the ethernet cable is disconnected, that chip mostly powers down. I think it's a Pi related thing rather than being inherent to Ethernet. In fact, if I were to guess, the energy per bit per meter of ethernet is probably far far lower than WiFi.