USB extension with hub

[Dave21w]

Currently I have my Raspberry Pi to run domoticz, I have 2 x 1.5M USB extension cables added so that I can put my RFXCom and Conbee II away from each other and the Pi. I would like to move the Pi to a different location but need to leave my RF devices roughly where they are, before I go ahead and buy one of these:-

https://www.amazon.co.uk/MutecPower-fem ... 5677&psc=1

Or something similar if anyone has other recommendations am i going to trash anything by putting this between the devices and the Pi, will the devices still appear on the same USB ports ?

I don't think I have to worry about voltage loss on the cable as I have checked and the RFXCom only draws 0.045A maximum and the Conbee II is probably very similar.

One other consideration would be to use a USB over ethernet option, that way I could cut my extension cord to a minimum length instead of having to use a fixed 5M one, especially if say I only need 4M.

TIA

[EddyG]

If you need those kind of distances, wouldn't a second Raspberry Pi with a slave Domoticz be a solution?

[Dave21w]

I'm trying to keep all the hardware that needs direct power in one location, also another instance of Domoticz is another point of potential failure but i do see your point.

[EddyG]

I have 1 Raspberry pi model 2B running for more the 622 days now, not really a point of failure.
It is still on Jessie and Domoticz v. 4.9700

[ronaldbro]

How many meters do you actually need?
The link you provided is a cable of 15 meters or more and with the ethernet solution you're talking about 4 meters...

If I google on max length of an USB cable I get 5m for high speed USB and 3m for low speed. If 4 meter is enough I would first try a simple 4 meter cable. When you're just over the specs I would first try a simple cable without any repeaters in it. And when it works it works

[Dave21w]

To be honest it probably is around 5M, think I was being a bit optimistic, I am curious why the USB over ethernet adapters (nothing more than a wiring conversion and back again) seem to think you can get far more than 5M without any repeater, any ideas ?

Although in regard to my original question if I were to use a single USB cable with a 4 port HUB on the end regardless of length how will this affect (if at all) the device addresses asigned to the RFXCom and Conbee2, will Domoticz still see them as being on the same ports and if not does it matter?

[ronaldbro]

I think the problem is a power drop, although I'm not an expert. Having a powered usb hub at the end of the cable could have a positive effect and a non powered hub a negative effect I think. Same problem occurs with very long ethernet cables.
USB over ethernet gives longer could be better because you convert to a different signal with different specifications. I think it will also give more flexibility because you can use your network. But I also think is that two converters give more room for error.

If it's 5m and you don't have a problem with getting the cable in place then I would still try a simple good quality cable of 5m first. If you don't have a good signal you can try a powered hub at the end (or in the middle). I wouldn't use a non powered hub.

If this doesn't work I personally would go for the second pi option. Then you can also use wifi, depending on your wifi quality.

[Dave21w]

I think some exact measurements are in order first, it's quite annoying as in a straight line I only 2M but as the wife wouldn't really appreciate a hole in the middle of the wall I have to take the long route

Update: 6M minimum

[ronaldbro]

Yep, thats always the case Although I wouldn't want a cable in sight too...

I just checked some USB over ethernet adapters. I have two wifi zigate adapters, which actually work very well with my wifi but I still would prefer wired... But I noticed that the cheaper ones only transfer the signal to a network cable, not a network. Switches in between are not supported. So probably they don't use TCP-IP. Also I can only find unbranded on ebay and ali express, my guess is that these are a real chance on failure.
The ones that do are very expensive.

There are some software solutions though. So if you want a cheap, flexible solution then maybe a Pi ZeroW with a software USB to ethernet could be a solution. Check this: https://derushadigital.com/other%20proj ... ZWave.html
Then also wifi can work...

Don't know what works better, this or a slave Domoticz. Although Slave domoticz doesn't work with every plugin. For my Mi-FloraMate I had to write a script to pass the data to my master Domoticz because the slave functionality didn't work with this plugin. And just passing the USB might be better to maintain...

I do find this an interesting topic

[Dave21w]

The reason all this started was because at present my Pi and it's UPS are on top of our kitchen cabinets (out of sight) but i wanted to move it to where the rest of my network stuff is in a rack under my stairs, all that stuff is on a UPS anyway but my Pi UPS is different so I need to move that too, it's a Din Rail mounted 5A 24v PSU that has a built in battery charging function and auto switch over, I then have a 24 to 5v 3amp switching converter so in the event of a mains fail my Pi will run for about 2 days on battery (probably longer) but I need to leave the RFXCom and Conbee2 where they are hence the USB cable length questions.

Interesting info in the link, I could use a serial to IP converter (I have a quite a few) however even though my RFXCom has already been modified for this approach I'm not sure I can do it with the Conbee2 (or a Raspbee as I have one of those too) as there's no where in Phoscon to set the type of interface used for the zigbee coordinator.

[ronaldbro]

Just another question... Is this really neccessary for your conbee? Zigbee is a mesh network, so if you have enough light bulbs which act as router it might not be any problem to move the conbee.

The solution in the link is all software, so with two Pi's you get USB network bridge...

[Dave21w]

I wish it wasn't, my conbee is in my kitchen (top of cupboard) and upstairs I have an Ikea router and I have a CC2531 flashed as a router in my garage (bottom of my garden) as I also have 3 zigbee devices there as well. I have a few Ikea lamps but only the Ikea switches have connected via the lamps, despite the other 2 routers being nearer to my Xiaomi sensors the only point they seem to want to talk to is direct to the coordinator despite there being a router nearer with an external antenna so the signal HAS to be stronger !

[ronaldbro]

You can switch to zigate On zigate I can now even bind a xiaomi sensor to a specified Ikea bulb and that works great. But this off topic...

I guess a simple 5m cable would still be the best option for you if it works. When it works it works and when it doesn't I would explore all other options.

[Dave21w]

I ended up buying the 10M cable with the 4 port hub on the end, checked the the supply voltage available at the hub with 2 devices plugged in and when i first tested it there was 4.6 volts there but then tested gain and it was 4.9, not sure if I had a bad connection on the USB socket at the Pi the first time, either way I decided not to risk the lower voltage possiblity. I have quite a few modules for voltage conversion etc so took apart the hub, removed the power feed and attached it to my mod board along with a ground connection then wired the output of the mod board to where the power feed should go, now I have 5.1v to the hub regardless of the input voltage so even if I loose a volt along the cable the hub and devices still get 5.1v so the signalling is fine.
Been running now for quite a few days with no issues

[ronaldbro]

Nice. When it works it works