6 ms·

I know that HN is crazy about their homelab setups, but please consider whether having a rats nest of jumpers and a breadboard in your comms cabinet is reliable

I know that HN is crazy about their homelab setups, but please consider whether having a rats nest of jumpers and a breadboard in your comms cabinet is reliable, let alone safe... How about a tweak to the BIOS to auto turn on power, then plug it into a Shelly Plug running Tasmota? You get your remote turn-on, you get a tested, reliable, and safe solution, and you get power use monitoring on top of that. The difference in price is ~ 10 eur where I'm at, and I'm not including the rest of the BOM of OP: Shelly Plug S: EUR 25 NodeMCU: EUR 12.5 Breadboard: EUR 3

gregmac 4y ago
Part of the motivation of "homelab" for many people is to learn in a practical way. If you're new to electronics or ESP32s, the amount you'd learning doing this is worth far more than 10 eur.
secure 4y ago
A smart plug would probably work just as well for most cases, but one downside is that you need to ensure your computer is safely powered off before turning off the smart plug. Conceptually, pressing the power button seems a little cleaner to me, and also works well with suspend-to-ram (what I originally wanted to do), which the smart plug can’t do. I’m not too concerned with safety — we’re talking about 3.3V (signal) and 5V (power) here.
- phoronixrly 4y ago
  You shut down your computer the usual way, from the OS, then toggle the plug to restart it. In case the system hangs during shut down, you'd actually want to know that it's hanging, which you can actually see in the power readings of the plug. > I’m not too concerned with safety I'm sorry to state that, but that much is evident from the photos in the blog post (assuming you're author here). While the voltages may look safe to you, the whole contraption is safe just until something goes wrong. Examples: 1. You push around a dangling wire and short out a more powerful circuit. 2. Something on your dev board for development purposes releases the grey smoke. 500mA at 5v may seem low to you, but under the right circumstances might cause a fire. I don't see any fuses or other overcurrent protection in your schematic. 3. Your mainboard gives a defect and runs more that the expected voltages/currents to your dev board. God forbid AC from something else faulty in the electric installation (just saying because I've been zapped from touching the outside of a closed case). 4. Power surges, lightning strikes... Static electricity even...
- KMnO4 4y ago
  Many smart plugs have some sort of energy monitor built in. I imagine you could turn off the plug when the power dropped below, eg, 5W.
- numpad0 4y ago
  Some motherboard BIOS has the “Restore on AC Power Loss” config item with options. I think that’s he is referring to. IIRC, each of which do following: - “Stay Off”: do nothing - “Power On”: turn on after AC is reconnected - “Last State”: turn on after AC is reconnected, only if disconnected while running
shiftpgdn 4y ago
Keep in mind a lot of smart plugs have remarkably low amperage limits.
- sowbug 4y ago
  Really? I've never seen one rated less than 15A, which is the same as NEMA 5-15R receptacles here in the US.
  - sokoloff 4y ago
    Sonoff R2 is rated at 10A. (I think several other models are as well, as a result of using a 10A relay.)
    - sowbug 4y ago
      Right you are. I'm surprised such things can be sold.
Kirby64 4y ago
Why would jumpers (specifically, DuPont connectors) be unreliable, or even unsafe? They're literally the method used in every single computer PC case in existence and work fine. I've never had one fail. I agree, breadboard is slightly problematic, but that could be fixed quickly with a soldered perfboard setup or a quick custom PCB and remove the breadboard component. The voltages we're talking about here is all 5V, and anything it's connected to should be pretty limited in current carrying capability.

gregmac 4y ago

Part of the motivation of "homelab" for many people is to learn in a practical way. If you're new to electronics or ESP32s, the amount you'd learning doing this is worth far more than 10 eur.

secure 4y ago

A smart plug would probably work just as well for most cases, but one downside is that you need to ensure your computer is safely powered off before turning off the smart plug. Conceptually, pressing the power button seems a little cleaner to me, and also works well with suspend-to-ram (what I originally wanted to do), which the smart plug can’t do. I’m not too concerned with safety — we’re talking about 3.3V (signal) and 5V (power) here.

phoronixrly 4y ago
You shut down your computer the usual way, from the OS, then toggle the plug to restart it. In case the system hangs during shut down, you'd actually want to know that it's hanging, which you can actually see in the power readings of the plug. > I’m not too concerned with safety I'm sorry to state that, but that much is evident from the photos in the blog post (assuming you're author here). While the voltages may look safe to you, the whole contraption is safe just until something goes wrong. Examples: 1. You push around a dangling wire and short out a more powerful circuit. 2. Something on your dev board for development purposes releases the grey smoke. 500mA at 5v may seem low to you, but under the right circumstances might cause a fire. I don't see any fuses or other overcurrent protection in your schematic. 3. Your mainboard gives a defect and runs more that the expected voltages/currents to your dev board. God forbid AC from something else faulty in the electric installation (just saying because I've been zapped from touching the outside of a closed case). 4. Power surges, lightning strikes... Static electricity even...
KMnO4 4y ago
Many smart plugs have some sort of energy monitor built in. I imagine you could turn off the plug when the power dropped below, eg, 5W.
numpad0 4y ago
Some motherboard BIOS has the “Restore on AC Power Loss” config item with options. I think that’s he is referring to. IIRC, each of which do following: - “Stay Off”: do nothing - “Power On”: turn on after AC is reconnected - “Last State”: turn on after AC is reconnected, only if disconnected while running

shiftpgdn 4y ago

Keep in mind a lot of smart plugs have remarkably low amperage limits.

sowbug 4y ago
Really? I've never seen one rated less than 15A, which is the same as NEMA 5-15R receptacles here in the US.
- sokoloff 4y ago
  Sonoff R2 is rated at 10A. (I think several other models are as well, as a result of using a 10A relay.)
  - sowbug 4y ago
    Right you are. I'm surprised such things can be sold.

Kirby64 4y ago

Why would jumpers (specifically, DuPont connectors) be unreliable, or even unsafe? They're literally the method used in every single computer PC case in existence and work fine. I've never had one fail. I agree, breadboard is slightly problematic, but that could be fixed quickly with a soldered perfboard setup or a quick custom PCB and remove the breadboard component. The voltages we're talking about here is all 5V, and anything it's connected to should be pretty limited in current carrying capability.