5 ms·

The 5W space is perhaps the space I understand the least. Things get weird at 5W. There's phones and tablets, but these aren't really general compute devices.

The 5W space is perhaps the space I understand the least. Things get weird at 5W. There's phones and tablets, but these aren't really general compute devices. But then comes these SBCs like Rasp. Pi, Rock 5B, Le Potato, Beaglebone Black, etc. etc. These use phone/tablet CPUs but in a form factor conductive to USB ports and HDMI ports... like a SFF Desktop. I've seen people say "Its a great small desktop!!", and hook up the Rasp. Pi (or whatever) to a $200 27" monitor drawing 80W and I'm just... confused by that. You're not making a good power-consumption argument, or a cost-benefit argument either, most of your costs are on the damn monitor (both in power and in $$$). I think there's value in the $60 7" screens though, which return the form factor closer to its Phone/Tablet roots. With such a small screen, the price is dramatically lower, while the power-consumption plummets to 5W SBC + 5W Screen (10W total). ----------- In theory, 10W total power consumption fits inside of 15.4W requirements on PoE. So there are real benefits to cutting the power consumption to an appropriate size. I guess there's also a myriad of "headless" applications where a 5W Rasp. Pi (or competing SBC) is useful. But in my experience, most of those headless applications should be a VM and/or Docker image instead. ---------- With that being said: this Rock 5B seems to draw 15W worst case, which leaves the available area for PoE. That could be fixed with a local battery pack (1270 Lead Acid packs are only $35) + some kind of power-controller to even out the power-draw. I admit that's a bit of custom electronics, but those kinds of custom-electronic problems are why we have ATMega / Arduino Unos laying around, right? :-)

chazeon 4y ago
Ubiquiti Wi-Fi 6 APs are requiring 20-ish watt PoE. I guess 15W SBC is not so much of issue for PoE?
- dragontamer 4y ago
  Do you have a link? My first search revealed: https://store.ui.com/products/u6-lite-us https://store.ui.com/products/u6-lite-us > Power method PoE, passive PoE (48V) > Max. power consumption 12W ------ > I guess 15W SBC is not so much of issue for PoE? Its not just 15W SBC, but also ~5W screen (assuming 7" screen). So it'd be closer to 20W worst case.
  - chazeon 4y ago
    I am talking about U6-Pro, specs here [pdf]: https://dl.ubnt.com/ds/u6-pro_ds https://dl.ubnt.com/ds/u6-pro_ds which is asking for a 48V, 0.5A PoE adapter, so should supports 24 W max. the consumption is listed to be 13W though. U6-LR is 17W.
    - dragontamer 4y ago
      Hmmm. https://en.wikipedia.org/wiki/Power_over_Ethernet#Two-_and_four-pair_Ethernet https://en.wikipedia.org/wiki/Power_over_Ethernet#Two-_and_f... > The original IEEE 802.3af-2003[1] PoE standard provides up to 15.4 W of DC power (minimum 44 V DC and 350 mA)[2][3] on each port.[4] Only 12.95 W is assured to be available at the powered device as some power dissipates in the cable.[5] Talking about original PoE standard here. Looks like 13W is closer to the practical maximum. -------- It looks like there are newer PoE+ and 4PPoE standards that increase the power. > U6-LR U6-LR requires the updated PoE+ standard which gives more power.
ly3xqhl8g9 4y ago
Haven't really heard the power consumption argument, perhaps it has increased in the last 12 months. In general the $35-70 SBCs (when they could be bought in retail) reveal an ugly truth: circa 99% of users don't ever need more than that in processing power/memory, even disk space with all the clouds for everything, hence all the $1,000+ machines (laptops, desktops, tablets, smartphones) are just massive overkill and a terrible waste.
- nordsieck 4y ago
  > In general the $35-70 SBCs (when they could be bought in retail) reveal an ugly truth: circa 99% of users don't ever need more than that in processing power/memory, even disk space with all the clouds for everything, hence all the $1,000+ machines (laptops, desktops, tablets, smartphones) are just massive overkill and a terrible waste. I suspect that quite a bit more than 1% of users play graphics heavy games or otherwise tax their machine beyond the practical limit of a cheap ARM SBC. If you'd said 2/3, I'd be much more inclined to agree.
  - ly3xqhl8g9 4y ago
    True, however it is going to be harder and harder to pay $2,000+ for a top GPU to play the latest AAA game, and it is going to easier and easier to pay ~$10/month for a cloud-rendered gaming subscription. Stadia was just cursed for being a non-ads-based Google product, GeForce Now seems to be thriving [1]. Somewhat funny is that the top 2 and 3 PC games most popular in 2022 have 1993 graphics, Minecraft and Roblox [2]. Another list puts Minecraft on 4 and Roblox on 3 [3]. [1] August 2022, GeForce Now Surpasses 20 Million Registered Users, https://gfnsource.com/article/218/GeForce-NOW-Surpasses-20-Million-Registered-Users https://gfnsource.com/article/218/GeForce-NOW-Surpasses-20-M... [2] https://activeplayer.io/top-15-most-popular-pc-games-of-2022/ https://activeplayer.io/top-15-most-popular-pc-games-of-2022... [3] https://twinfinite.net/2022/10/most-played-games/ https://twinfinite.net/2022/10/most-played-games/
bri3d 4y ago
I also don't get people who use these for desktops or especially homelab servers. It's never made sense to me. But, I really like them for "computer that's a computer rather than a microcontroller, but closer to the Real World than a Real Computer." These little boards usually offer GPIO, SPI, I2C, and sometimes even CAN natively, which makes them awesome for plugging into real world devices without needing another microcontroller hop in the middle. I've used boards in this 5-10W class for automotive reverse engineering, higher-order drone control like computer vision / flight planning (paired with a microcontroller for the hard-realtime control loop), and robotics. I think they're awesome for that use case.
- dragontamer 4y ago
  > (paired with a microcontroller for the hard-realtime control loop) In theory, the Beaglebone SBCs are excellent for this. The Beaglebone Black (2014 era design, but still works) has Hard-Realtime PRUs for those kinds of loops. More recent Beaglebone AI (2018ish) has a Cortex-A + 2xArm Cortex-M4, so two embedded microcontrollers for you to use onboard. The most recent Beaglebone AI 64 has a Cortex-A main-core + Cortex-R cores for guaranteed realtime operations. Oh yeah, and those PRUs never went away either.
VLM 4y ago
802.3af was the old turn of the century standard limit of 15 watts. You can probably buy new stuff used but everything is probably 802.3at now from around a decade ago, which is twice the power 30 watts. There is a new standard came out about covid era that AFAIK is totally vaporware at this time and that goes up to 70 watts for charging laptops or whatever nonsense. WRT the newest plus products I'm a little puzzled how they put 77 volts on something rated by the fire dept and NEC as "low voltage" but that's not my paygrade LOL. The $10 to $20 price point for "PoE Splitters" runs around 15 watts at 5v fixed and you're going to have to pay the $20 to $30 price point if you want selectable 5 / 9 / 12 volt output and more than 25 watts or so. The place to buy these things is the security camera field. They're all about wanting a couple amps at 12 volts for IR illuminators off a PoE cable and applications similar to that. Like a lot of no-name power equipment don't expect it to last in hot summers in an attic and don't expect to run at 99% of listed current for very long without overheating. Its better than the totally fake budget USB charger market or mostly fake ratings PC power supply market, but its not like buying engineering stuff from big names where you can trust the ratings (like a Mean Well 15 watt industrial supply will actually output 15 watts at industrial temps for a decade or so, at least so far, but you'll pay $$$ for real true ratings as opposed to consumer imaginary ratings) If you actually need 15 watts I'd buy a "25 probably fake watts" splitter and expect a long life from it for less than $30 delivered. The market price was about "fifty bucks" for similar just a couple years ago.
- dragontamer 4y ago
  > I'm a little puzzled how they put 77 volts on something rated by the fire dept and NEC as "low voltage" but that's not my paygrade LOL. The newer standard uses all 4 twisted pairs, so its 71W power / 48V / 4 wires == 370mA on the average on each pair of wires. Though "worst case" 960mA due to unbalanced power draw it seems. The 4PPoE standards also run with 1Gbps protocol, meaning all 4 twisted pairs are data. So all 4 are data + power. I'm not quite sure how it all works electrically... though I loathe to be the guy to design the splitters to pull power evenly from 4 different pairs.
- aidenn0 4y ago
  The highest I've seen is 48V, which is under the 50V "low voltage" limitation.
PragmaticPulp 4y ago
> With that being said: this Rock 5B seems to draw 15W worst case, which leaves the available area for PoE. There are additional PoE standards extending up to about 71W at the client device: https://en.wikipedia.org/wiki/Power_over_Ethernet#Standard_implementation https://en.wikipedia.org/wiki/Power_over_Ethernet#Standard_i... 802.3at, aka PoE+, can deliver 25W and is not hard to find even on affordable switches.

chazeon 4y ago

Ubiquiti Wi-Fi 6 APs are requiring 20-ish watt PoE. I guess 15W SBC is not so much of issue for PoE?

dragontamer 4y ago
Do you have a link? My first search revealed: https://store.ui.com/products/u6-lite-us https://store.ui.com/products/u6-lite-us > Power method PoE, passive PoE (48V) > Max. power consumption 12W ------ > I guess 15W SBC is not so much of issue for PoE? Its not just 15W SBC, but also ~5W screen (assuming 7" screen). So it'd be closer to 20W worst case.
- chazeon 4y ago
  I am talking about U6-Pro, specs here [pdf]: https://dl.ubnt.com/ds/u6-pro_ds https://dl.ubnt.com/ds/u6-pro_ds which is asking for a 48V, 0.5A PoE adapter, so should supports 24 W max. the consumption is listed to be 13W though. U6-LR is 17W.
  - dragontamer 4y ago
    Hmmm. https://en.wikipedia.org/wiki/Power_over_Ethernet#Two-_and_four-pair_Ethernet https://en.wikipedia.org/wiki/Power_over_Ethernet#Two-_and_f... > The original IEEE 802.3af-2003[1] PoE standard provides up to 15.4 W of DC power (minimum 44 V DC and 350 mA)[2][3] on each port.[4] Only 12.95 W is assured to be available at the powered device as some power dissipates in the cable.[5] Talking about original PoE standard here. Looks like 13W is closer to the practical maximum. -------- It looks like there are newer PoE+ and 4PPoE standards that increase the power. > U6-LR U6-LR requires the updated PoE+ standard which gives more power.

ly3xqhl8g9 4y ago

Haven't really heard the power consumption argument, perhaps it has increased in the last 12 months. In general the $35-70 SBCs (when they could be bought in retail) reveal an ugly truth: circa 99% of users don't ever need more than that in processing power/memory, even disk space with all the clouds for everything, hence all the $1,000+ machines (laptops, desktops, tablets, smartphones) are just massive overkill and a terrible waste.

nordsieck 4y ago
> In general the $35-70 SBCs (when they could be bought in retail) reveal an ugly truth: circa 99% of users don't ever need more than that in processing power/memory, even disk space with all the clouds for everything, hence all the $1,000+ machines (laptops, desktops, tablets, smartphones) are just massive overkill and a terrible waste. I suspect that quite a bit more than 1% of users play graphics heavy games or otherwise tax their machine beyond the practical limit of a cheap ARM SBC. If you'd said 2/3, I'd be much more inclined to agree.
- ly3xqhl8g9 4y ago
  True, however it is going to be harder and harder to pay $2,000+ for a top GPU to play the latest AAA game, and it is going to easier and easier to pay ~$10/month for a cloud-rendered gaming subscription. Stadia was just cursed for being a non-ads-based Google product, GeForce Now seems to be thriving [1]. Somewhat funny is that the top 2 and 3 PC games most popular in 2022 have 1993 graphics, Minecraft and Roblox [2]. Another list puts Minecraft on 4 and Roblox on 3 [3]. [1] August 2022, GeForce Now Surpasses 20 Million Registered Users, https://gfnsource.com/article/218/GeForce-NOW-Surpasses-20-Million-Registered-Users https://gfnsource.com/article/218/GeForce-NOW-Surpasses-20-M... [2] https://activeplayer.io/top-15-most-popular-pc-games-of-2022/ https://activeplayer.io/top-15-most-popular-pc-games-of-2022... [3] https://twinfinite.net/2022/10/most-played-games/ https://twinfinite.net/2022/10/most-played-games/

bri3d 4y ago

I also don't get people who use these for desktops or especially homelab servers. It's never made sense to me. But, I really like them for "computer that's a computer rather than a microcontroller, but closer to the Real World than a Real Computer." These little boards usually offer GPIO, SPI, I2C, and sometimes even CAN natively, which makes them awesome for plugging into real world devices without needing another microcontroller hop in the middle. I've used boards in this 5-10W class for automotive reverse engineering, higher-order drone control like computer vision / flight planning (paired with a microcontroller for the hard-realtime control loop), and robotics. I think they're awesome for that use case.

dragontamer 4y ago
> (paired with a microcontroller for the hard-realtime control loop) In theory, the Beaglebone SBCs are excellent for this. The Beaglebone Black (2014 era design, but still works) has Hard-Realtime PRUs for those kinds of loops. More recent Beaglebone AI (2018ish) has a Cortex-A + 2xArm Cortex-M4, so two embedded microcontrollers for you to use onboard. The most recent Beaglebone AI 64 has a Cortex-A main-core + Cortex-R cores for guaranteed realtime operations. Oh yeah, and those PRUs never went away either.

VLM 4y ago

802.3af was the old turn of the century standard limit of 15 watts. You can probably buy new stuff used but everything is probably 802.3at now from around a decade ago, which is twice the power 30 watts. There is a new standard came out about covid era that AFAIK is totally vaporware at this time and that goes up to 70 watts for charging laptops or whatever nonsense. WRT the newest plus products I'm a little puzzled how they put 77 volts on something rated by the fire dept and NEC as "low voltage" but that's not my paygrade LOL. The $10 to $20 price point for "PoE Splitters" runs around 15 watts at 5v fixed and you're going to have to pay the $20 to $30 price point if you want selectable 5 / 9 / 12 volt output and more than 25 watts or so. The place to buy these things is the security camera field. They're all about wanting a couple amps at 12 volts for IR illuminators off a PoE cable and applications similar to that. Like a lot of no-name power equipment don't expect it to last in hot summers in an attic and don't expect to run at 99% of listed current for very long without overheating. Its better than the totally fake budget USB charger market or mostly fake ratings PC power supply market, but its not like buying engineering stuff from big names where you can trust the ratings (like a Mean Well 15 watt industrial supply will actually output 15 watts at industrial temps for a decade or so, at least so far, but you'll pay $$$ for real true ratings as opposed to consumer imaginary ratings) If you actually need 15 watts I'd buy a "25 probably fake watts" splitter and expect a long life from it for less than $30 delivered. The market price was about "fifty bucks" for similar just a couple years ago.

dragontamer 4y ago
> I'm a little puzzled how they put 77 volts on something rated by the fire dept and NEC as "low voltage" but that's not my paygrade LOL. The newer standard uses all 4 twisted pairs, so its 71W power / 48V / 4 wires == 370mA on the average on each pair of wires. Though "worst case" 960mA due to unbalanced power draw it seems. The 4PPoE standards also run with 1Gbps protocol, meaning all 4 twisted pairs are data. So all 4 are data + power. I'm not quite sure how it all works electrically... though I loathe to be the guy to design the splitters to pull power evenly from 4 different pairs.
aidenn0 4y ago
The highest I've seen is 48V, which is under the 50V "low voltage" limitation.

PragmaticPulp 4y ago

> With that being said: this Rock 5B seems to draw 15W worst case, which leaves the available area for PoE. There are additional PoE standards extending up to about 71W at the client device: https://en.wikipedia.org/wiki/Power_over_Ethernet#Standard_implementation https://en.wikipedia.org/wiki/Power_over_Ethernet#Standard_i... 802.3at, aka PoE+, can deliver 25W and is not hard to find even on affordable switches.