USB Controlled power passthru

Ello, I’m fighting a flaky cable modem or my ISP is good at pushing firmware’s that require the cable modem to reboot to regain service. Since I’m a cord-cutter and cell service a really bad (but not non-existent), I’m looking for a way to programmatically to cut and restore power to my cable modem.

I’ve looked at aware power bars but most of them are also doing power conditioning. Since my cable modem is also on a UPS, I can’t have additional line conditioning after that. So im either looking for something that is basically a USB controlled power relay.

It could me cut from the NEMA outlet side or on the cable modem’s DC side.

I’ve seen some NEMA based USB controlled sockets, but they seem to be 100+ USD. To me that seems a bit much in price. Especially when the power usage I need is pretty low.


Also, if the device is networked, it cannot be able to phone out or have ‘cloud’ requirements.

Openhab with a z-wave plug?

That’s an awful lot of overkill for me. I currently don’t have any home automation infrastructure in my house.

That sort of why I like the idea of the kill switch as a USB device. No networking technologies/insecurities to worry about.

Couldn’t you just provide your own modem and avoid the updates that way? Would save on modem rental fees.

@lesser, Not sure if the issues is the firmwares or just the service. I live in a pretty rural area. As for saving money, my equipment rental is “included” in the level of service I have with Spectrum. :expressionless:

Actually, I may have another idea of how to deal with my outage. Since I run pfSense as my router, I have some scripting options. I just remembered the Arris/Motorola diagnostics page. It would be great if I could get to that even when my connection was live. Even if I can’t, I can detect when my WAN address switches to 192.168.100.x and then I HTML scrap the Arris cable modem diagnostics page and force a cable modem to reboot.

Doesnt necessarily work that way. Comcast for instance will provide firmware upgrades to customer owned modems. Most of the time this firmware is actually from the modem maker and not the ISP. The ISP merely just pushes it out.

Comcast for instance tests it. Actually from what I have read, all “Retail” modems on their supported device list have been tested to work on their network.

Though with some ISP’s they will accept retail modems but not provide any support for them. As in no updates at all.

Spectrum is known for using Puma 6 modems. The Intel Puma 6 chip has issues. Its well documented over at So much so Arris is getting or has been sued over the SB6190. So if its a Puma 6 modem that could be why its “Flaky” .

I’ve got a Hitron E31N2V1 cable modem. It also has 2 VoIP interfaces too. Probably should start researching it. To see if that’s the source of my headaches.

Why not buying a Pi Zero W and a simple relay hooked up to it through GPIO. You could make a 5 lines python script periodically launched through cron.

P.S. you could even use a Pi Zero non wireless if you want to be cheap, but I’d suggest getting a wifi dongle anyway so that in case of a power loss it can set the time back correctly. Also you could make the SD read only and that would pretty much make it bulletproof

I was thinking about that for another project in the past that had a larger power requirement. That’s where I may have to go again.

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I think it’s the most cost effective solution. I also just remembered that you can use a NodeMCU if you want that’s even more basic and cheap, with wifi always included. I don’t know how you’d go about programming into it the power on and off but I’m sure you could do it no problem

So it looks like I’m building an RPI controlled power outlet. Here’s my general plan.

  • Plastic 2 ganger box
  • Rpi Zero W
  • KNACRO 2-Channel 5V Relay Module High/Low Level Triggering Optocoupler Isolation Load 30A DC 30V / AC 250V
  • GFCI Outlet dual outlet
  • USB power supply
  • capacitors???

My big question is I’m looking for a good small form factor USB power converter from 120vAC to 5vDC (USB) power supply. I obviously have 120vAC to the enclosure already. I don’t need much power 2 amps at most. The base RPi Zero W uses 700mA. Most of the relays I’m looking at using about 200mA on top of that. Searching for stuff like this is always a pain because of so many false positives. What are people’s recommendations?

What do you mean false positives?