Episode #125 of the Stack Overflow podcast is here. We talk Tilde Club and mechanical keyboards. Listen now

Hot answers tagged

11

Like @SteveRobillard stated in his comment, it's probably best just to buy the powered hub first and save you the possible trouble of not having it in the first place if you needed it. There are OTG [On the Go] hubs, which are micro usb. They work a bit differently than a standard usb hub, which uses a barrel jack for power. This one from eBay is extremely ...


10

There is only a problem if you have two 5V supplies fighting with each other. I quite often back power early model Pis, but if I'm doing so I don't also power via the expansion header or the microUSB socket. By the way you can't back power the B+ or A+ or Pi2 via the USB sockets. Circuitry has been added to stop current inrush problems which used to crash ...


6

The default pi kernel may or may not have the right drivers built in to mount the external drive without the root filesystem,1 so the first thing you'll have to do is investigate that and if it doesn't, build a kernel that does. It's probably okay (various blog posts online imply a custom kernel is not generally needed), but this is important to note just ...


6

You can get a USB hub that stacks in the same footprint as your Pi and this model even alllows you to maintain access to the GPIO pins. Note these come in two models, one for the original Pi Zero and one for the Pi Zero with camera connector.


5

The Hubpixed is not a power hub, but it draws power directly from the main board and therefore you should be good. It does not require any cable or soldering and connects seamlessly to the Pi Zero.


5

Binding and unbinding the driver for the hub itself will cause anything connected to it to be registered and appear in lsusb. Unloading and reloading the driver module itself might also work, but for that you'd have to build your own kernel, since it is built into the stock one used on Raspbian, etc. Note this driver is also needed for the Pi's build in ...


5

Unfortunately not. USB hubs have active circuitry that controls the data flow (and also power requirements) of slave devices. You could strip the circuitry out of a USB hub, although I'm not sure how much space you would save by doing that.


5

I doubt it would work, according to this page: USB - port power limits the Raspberry Pi USB ports are designed to handle 100mA each so the advice is to always use an external hub with its own power supply for a USB hard drive (and other "high-power" devices).


4

Here's a method for controlling the power to ports on a USB hub, using software - the hub-ctrl.c app from a Raspberry Pi question that another post above links to. It can be used to wake up the USB ports (at a regular interval using a cron-job script or over a SSH connection if only some devices attached to the USB bus have stopped). Some useful information ...


4

Theoretically it is impossible to backpower a PI3 (or other modern models). However tests by a member indicate that if the Pi is powered on, it will remain powered through the hub. This is arguably a bug in the Pi (actually a consequence of the very simple USB interface, which is a long way from being standards compliant). There is no "fix", other than ...


4

Will the read speed of each hdd drop the more hdds I add due to the pi usb controller? This is exactly what will happen. Connecting multiple HDDs (and the more so SSDs) to an RPi to increase disk throughput is a waste of effort. The RPi cannot transfer data faster than ~25 MB/s, no matter how many disks you connect to it. I won't go into details regarding ...


4

It looks like you are asking for a tailored solution for your DiY project. Well I think the following links can point you to right direction as these are tutorials for interfacing RaspPi to Azure IoT hub service. Its very detailed and will certainly provide the barebones of your project : https://docs.microsoft.com/en-us/azure/iot-hub/iot-hub-raspberry-pi-...


3

You likely blew the polyfuse. But, pins GPIO pins +5V and ground (2 and 6) could be used to power Raspberry Pi as well. That pin is connected after polyfuse, so if you power it this way you may well bypass your blown polyfuse. https://www.raspberrypi.org/forums/viewtopic.php?f=44&t=10500 Be aware, this will cicrumvent protection that polyfuse gives. ...


3

I managed to figure out the possible problem myself. However, I didn't find an elegant solution to that. The problem does not occur upon disconnection. Actually it occurs upon connection. Every time my Pi connects to my Bluetooth GPS module, or my laptop connects to my Pi, the state of hci0 changes from "UP RUNNING PSCAN" to "UP RUNNING", and prevents ...


3

YES YOU CAN! BUT.... here is what you have to do for it to work out. First off, you can't power-on the Pi2B just over a USB-Hub for example. You always need to start it up using the classical method with the micro-usb-connector. But after it's booted up, you can happily remove the micro-usb-connector leaving it just powered up over the USB-Port/Hub. Only ...


3

You should be able to, although as per my comments it probably is not necessary; all you need is a commonplace OTG adapter. Based on the wikipedia description, however, you could make one yourself using one end of a normal microUSB cable and a female USB jack from somewhere (here's someone who has), since that is the context: You need to insert the male end ...


3

I already have an OTG hub that works fine either powered or not as described here, but note when the hub is powered, it must be used to provide power to the Pi, since otherwise there would be two competing power sources and that is a bad thing. But I decided to try this with an ordinary (optionally powered) USB hub, and ended up with a similar answer to ...


3

Sorry, that wont work. Only the 'master' Pi0, plugged in to the 'uplink' port using a OTG cable can use the gadgets, among which all the other Pi0's and the builtin Ethernet adapter. You could configure network over USB and configure the master Pi0 to route the other Pi0's traffic over the one Ethernet port. Probably this is somewhat too hard for someone ...


3

Thanks to gadgetoid and niko over on the Pimoroni forums it seems the fix was twofold: Cut the 5v+ wire on the USB cable (assuming you're powering it separately than the Pi) Add a 1k resistor between pins 1 and 9 on the Pi's GPIO (3v3 and GND) There is more info about individual hub models here. Mine is the Belkin F5U404 Hi-Speed USB 2.0 4-Port Mobile Hub ...


2

@conrad_heimbold is right, and editing /boot/cmdline.txt with the PARTUUID will actually boot your Pi. However, he is wrong in one place. If you place quotemarks around the PARTUUID, your Pi will fail to boot, but if you remove them, it will boot up with no issues. ie this works: root=PARTUUID=abcdef01-01 rootfstype=f2fs rw rootwait BLAH BLAH BLAH but ...


2

The default pi kernel can not handle UUIDs, only PARTUUIDs. To be more detailed: UUIDS depend on the file system of the partition PARTUUIDS do NOT depend on the file system of the partition This answer in an archwiki forum explains the difference between UUIDs and PARTUUIDs more detailed. So if the default pi kernel does not support the mentioned file ...


2

You don't need to let a USB drive take over. A large SD card can hold the complete Linux installation. What you can do, is to let the Pi mount the drives at various locations (like /mydisks/torrent) during boot time, and then configure the services you need to use to have their data on the appropriate disk. Note that you will want ext4 or similar as file ...


2

Wireless keyboards could operate by using radio frequency (RF) or infrared (IR). RF techniques range from 27 MHz to up to 2.4 GHz (according to wikipedia). With Bluetooth being a widely used technology. While both WiFi and Bluetooth share the 2.4 GHz band they differ both in technical aspects as well as in their objective. So in short: Your (presumed) ...


2

Q1. The Pi B has a 1.1 amp microUSB polyfuse. The Pi B+ and Pi2 have 2.2 amp microUSB polyfuse. Q2. You can Google as well as me. You could always use several in parallel if you can't find a suitable single unit.


2

Well I am not sure if that is a good idea, because LAN is powered on the same CHIP as the USB HUB. It may also be that you are trying to do these commands too quickly in that loop. You assume it takes that amount of time to come back up, but maybe there are other things that need to be reloaded and it hangs. I cannot see why this would be beneficial.


2

From man ifconfig: NOTE This program is obsolete! For replacement check ip addr and ip link. Although that's not the problem here (it still works fine), I thought I'd point that out. The issue is: If no arguments are given, ifconfig displays the status of the currently active interfaces [...] if a single -a argument is given, it displays ...


2

Its reasonably likely that you blew the fuse. The Raspberry Pi has a polyfuse, which will "blow" if you draw too much power from the Pi. A quirk of polyfuses is that they can take a long time to reset. Set your Pi aside, and try using it again in a few hours, or tomorrow even. Google "Raspberry Pi polyfuse" for more info.


2

I advise you don’t fret and choose usb hubs, which has many ports with different connectors. I have this one. Model hi-speed 7-Port Ultra-Mini Hub provides USB ports for Plug-and-Play connectivity to USB 1.1 and USB 2.0 devices. Data transfer rate of this hub reaches the level of 480Mbps.


2

It is possible it may work. If you plug the big USB into the HUB and your power supply USB into the big USB which is plugged intot he HUB, then the small USB into the Pi power, that should provide power to everything. Then you plug the USB HUB, USB host cable into the Pi and that should recognise the HUB in Raspian. Theoretically you will have 3 usable ...


2

There are video grabbers which can forward video from 4 analogue cameras into single USB port. Grabbing is software multiplexed, so don't expect more then few frames per second.


Only top voted, non community-wiki answers of a minimum length are eligible