At my workplace we had a farm of laptop machines and we weren't allowed to disassemble them to pull any power wires out. What we ended up using was a remotely controlled motor with a small plastic "finger" attached that would press on the power button for n seconds, depress, wait few seconds, then press it for n seconds again to do remote hard reboots.
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.<p>The difference in price is ~ 10 eur where I'm at, and I'm not including the rest of the BOM of OP:<p>Shelly Plug S: EUR 25<p>NodeMCU: EUR 12.5
Breadboard: EUR 3
Great project but a little too much for the ones of us with only software development skills.<p>I use smart plugs over Wi-Fi to do that. Shelly Plug S have a small physical button, a web app, a HTTP URL to call to switch the plug on or off. They also have a lot of features that I don't need. Among them MQTT and Alexa/Google integrations. A few bash scripts with curl and I can do everything I need. The price is reasonable and they saved me a lot of time.
The rationale to justify the wifi link is interesting, and this is a creative solution indeed!<p>In the past I've used wake-on-lan cards but with the wake signal connected to the reset line instead, so it became reset-on-lan. That's much more useful in my lab, I don't know about yours!<p>Edit: Writeup: <a href="https://www.i3detroit.org/reset-on-lan-an-ethernet-aware-remote-reboot-device-from-junkbox-parts/" rel="nofollow">https://www.i3detroit.org/reset-on-lan-an-ethernet-aware-rem...</a>
This is a neat writeup. I think the ESP32, alongside similar microcontrollers that tie communication via complex protocols so close to direct interaction with the physical world for such a small energy cost, are really amazing for teaching, inspiring, and empowering otherwise "non-technical" people. Of course, you do have to be able to program, but I think we're making great strides in making that as easy as possible with things like CircuitPython and EduBlocks.<p>Also, this kind of shocked me:<p>> none of my followers had ever seen functioning WOL on any 10 Gbit/s card.<p>Those cards are <i>way too expensive</i> to be lacking such a useful feature!
No electronics skills, flashing of firmware, etc. is needed. Just order a USB relay board and hook NO and COM terminals to the power switch. Can be driven from a cheap Rasberry Pi or any other low power mini PC.
15-20 years ago if you were using a cheap dedicated hosting company that stacked "servers" in desktop cases on wire racks and somehow offered instant remote reboots despite clearly being too cheap to buy switched PDUs, they were doing something just like this.
Crazy good ESPHome story here!<p>> <i>I wanted a quick solution (with ideally no custom firmware development) and was already familiar with ESPHome, which turns out to very easily implement the functionality I wanted :)</i><p>> <i>In addition to a standard ESPHome configuration, I have added the following lines to make the GPIO pin available through MQTT, and make it a momentary switch instead of a toggle switch, so that it briefly presses the power button and doesn’t hold the power button:</i><p>Really simple looking understandable yaml.file constitutes almost all the softwafe development done for this project. Stunning. Nice.
Few years ago I did the same thing with a raspberry pi zero W and two bash scripts - one for power on/off one for reset. It's quite useful to have and was born out of the need to reboot my Ryzen 1700x powered pc, due to p(ower)state bug that I only uncovered as the culprit a year ago.<p>Here's a simple writeup with pictures : <a href="https://1drv.ms/u/s!Au9Lr9dxN7gUs8AQo6pkvUxXb1DD4g?e=DCqDzG" rel="nofollow">https://1drv.ms/u/s!Au9Lr9dxN7gUs8AQo6pkvUxXb1DD4g?e=DCqDzG</a>
I want this feature. Power cycle a machine from somewhere else. The smart PDU strips are suspiciously complicated and expensive enough that I don't want to discover I bought an unreliable one.<p>Current thinking is a relay held open by power over ethernet and toggle the switch port to reboot it, but I don't quite have the nerve to solder the relay myself. I can't deal with a dead/crashed switch remotely anyway.
A mosfet seems pretty overkill for this instead of practically any cheaper transistor unless there’s something about motherboard headers I don’t know. Pretty cool though.