jhickie
Posts: 3
Joined: Thu Oct 17, 2019 9:16 pm

Issues with the K400 keyboard

Thu Oct 17, 2019 9:35 pm

Hello everyone. I am new to the RPi and really excited to dig in. I got it to replace my media center in the living room, which is currently powered by an aging computer, as well as to be a retro gaming console via RetroPie. I got the RPi 3+ B, downloaded the newest NOOBS and installed Raspian with no issues. However, I am completely unable to get my Logitech K400 wireless keyboard/trackpad to recognize or pair.

My K400 has never had issues with any PC I've paired it to previously, totally PnP. I just tested it today on my main PC through the Logitech Unifying Software (not aging media center PC) and it paired with no issues. While it was paired, I made sure to verify that the K400's firmware is up to date. However, when I try to pair it to the RPi it doesn't recognize. I've tried to pair it through the Bluetooth interface icon (upper-right) and I've tried to use the keyboard config tool in the menu. I've tried to unplug it and re-plug it in the desktop environment. I've tried to pair it through the console. Nothing works.

I've searched high and low for 3 days, looking through countless forum posts and Google search results. I did read through another post here on the forums regarding the K400 (https://www.raspberrypi.org/forums/view ... 0#p1531089) but the only solution I've seen that I haven't tried yet is to install the Logitech Unifying Software through Solaar, but I am unsure how to do that. I guess I have a couple of questions:

1. Why is everyone seemingly having no issues with using the K400 out of the box with the RPi? Am I doing something wrong as a true RPi noob?
2. Do I install Solaar through the repo via the console, or is there something else I have to do to get it running? If the former, would someone be kind enough to link me to instructions?

I really want to find out how to get this working. I am about 12 feet from my TV so a wired connection is not really feasible, and I don't really want to just buy another wireless keyboard/trackpad combo only to have the same thing happen. If anyone can help this RPi rookie to get this thing working, I would be so grateful.

Thank you!

humbug
Posts: 11
Joined: Thu Jun 06, 2013 11:42 pm

Re: Issues with the K400 keyboard

Sun Oct 20, 2019 3:30 pm

I have 3 slightly different K400s - K400r, K400+ and K400 plus and all work on Pis models 0 to 4.
None of those models use Bluetooth they are all USB wireless.
All have worked out of the box after plugging in the dongle without any additional software on the Pis.
I have never tried NOOBS I have alwas used the latest Rapbian and it has always worked.

Are you sure that you have a Bluetooth enabled version of the K400, I have never seen one but.......

If you plug in the USB dongle and it is not recognised you have another problem and experience suggests that
an inadequate power supply can cause such issues. What power supply are you using?

Are you plugging the dongle directly to the USB socket or are you using a USB hub?
I have had problems when using an unpowwered hub but powereed hubs do work.

Good luck,

John

alphanumeric
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Re: Issues with the K400 keyboard

Sun Oct 20, 2019 8:00 pm

Once its paired to the Unifying Dongle, there should be no need to re pair it? As far as the PC / Pi is concerned its just a USB HID device. It thinks its a wired USB keyboard mouse. I have one of the original K400's. It has always "just worked" with any PI or PC I've plugged the dongle into. It even works in the BIOS on my PC.
That being said, I have yet to ever get it to connect via Bluetooth to a PC without the Unifying Dongle. I have heard that it can be done on a Pi. I haven't tried it as I use it on several different Pi's, its just easier to plug in the Unifying dongle than pair and re pair etc.

jhickie
Posts: 3
Joined: Thu Oct 17, 2019 9:16 pm

Re: Issues with the K400 keyboard

Mon Oct 21, 2019 9:54 pm

I really appreciate the help, thanks for reading!

To clarify the information in my post..

I have the K400+ and it is indeed the wireless USB variety, not bluetooth. The USB dongle has never failed me before, always just working as plug and play. I downloaded the Logitech Unifying Software on my other computer to test this K400+ and make sure it was working, once I was having trouble connecting to my RPi.

I used NOOBS to install the newest version of Raspbian when I set up the RPi. NOOBS is just the delivery system for installing various OS. It comes Raspbian and LibreELEC (Kodi). When you connect to wifi, you can get a whole list of alternate OS to install through this NOOBS interface, but I just installed Raspbian and LibreELEC. You can select which OS to boot to on startup.

I had no idea power could be an issue with peripherals.. this is just a USB dongle, how much power could it require? I have attached a pic of the specs from my power adapter.
IMG_20191021_122233.jpg
power adapter specs
IMG_20191021_122233.jpg (94.13 KiB) Viewed 645 times
Regarding pairing, does the dongle itself retain pairing information? I would think this information is stored on the receiving computer, but I've been wrong before! If this is the case, I'll go pair this keyboard to the dongle using my other computer, and then reattempt to connect to the RPi. That would be a very easy solution and I'm already crossing my fingers.

Not sure if it matters, but I use another Logitech dongle for my keyboard and mouse on my main computer in my office. Only the keyboard and mouse I have paired are showing up in the connection list of the unifying software. I paired the K400+ to this computer with no problems and then unpaired it when I was testing this issue.

Please let me know if I'm doing something wrong or if my power adapter is an issue. I've built plenty of PC's but this RPi is making me feel like a beginner. Thanks for the advice and for taking the time to help!

RossDv8
Posts: 159
Joined: Thu Jan 21, 2016 12:35 pm

Re: Issues with the K400 keyboard

Tue Oct 22, 2019 1:49 am

I should have read the original post in more detail. The answer was to a different k400 problem
Last edited by RossDv8 on Tue Oct 22, 2019 2:05 am, edited 4 times in total.
Pi 4B 4GB - system on WD 240G SSD ( but /boot on Sandisk microSD)

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HawaiianPi
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Location: Aloha, Oregon USA

Re: Issues with the K400 keyboard

Tue Oct 22, 2019 1:51 am

jhickie wrote:
Mon Oct 21, 2019 9:54 pm
I had no idea power could be an issue with peripherals.. this is just a USB dongle, how much power could it require?
Not much, the Unifying dongles are very power efficient.

Regarding pairing, does the dongle itself retain pairing information? I would think this information is stored on the receiving computer
Nope, it appears to be stored on both Unifying devices (the dongle, and what it's paired to), and you cannot have the same device paired to multiple dongles (unfortunately). If you only have one device and dongle and you are moving the dongle between your Pi and another computer, then it should just work. If you are trying to use a different dongle on the Pi and another computer with the same Unifying keyboard, that will never work (believe me, I've tried).

Not sure if it matters, but I use another Logitech dongle for my keyboard and mouse on my main computer in my office. Only the keyboard and mouse I have paired are showing up in the connection list of the unifying software. I paired the K400+ to this computer with no problems and then unpaired it when I was testing this issue.
Aha! I suspect we have found the problem. Well, part of it anyway. When you paired the keyboard to another dongle you essentially unpaired the original dongle. I'm not sure why it didn't work for you in the first place, but you definitely need to re-pair it with the dongle you are using with the Pi now.

You can have multiple devices paired to a single dongle, but you cannot have one device paired to multiple dongles (wish you could). If you attempt to do so, the device will only function with the last dongle it was paired with (it will still show up in the other dongle's pairing settings, but it will not function).


EDIT:
There is a utility in the Raspbian repos called Solaar, which will allow you to pair and unpair Unifying devices in Linux.

Code: Select all

sudo apt install solaar
Last edited by HawaiianPi on Tue Oct 22, 2019 2:00 am, edited 1 time in total.
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?

humbug
Posts: 11
Joined: Thu Jun 06, 2013 11:42 pm

Re: Issues with the K400 keyboard

Tue Oct 22, 2019 2:00 am

The power adapter that you are using should be O.K. as it is capable of supplying 2.5amps which meets the 3b+ spec.

I have just set up my 3b+ to use the K400r keyboard (was on my rpi4) and it works without any problems using a 2.5amp supply.

Do you have anything else plugged into the USB sockets?

Can you plug the USB dongle into your main machine and see if the keyboard works there - if possible remove the existing dongle first.
You should not need to use the unifying software it should just work no need to do any pairing activity. From your info I am not sure if you have already done this or if you just paired with the existing dongle in your main PC.

John

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davidcoton
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Re: Issues with the K400 keyboard

Tue Oct 22, 2019 10:07 am

HawaiianPi wrote:
Tue Oct 22, 2019 1:51 am
You can have multiple devices paired to a single dongle, but you cannot have one device paired to multiple dongles (wish you could).
Think about that for a moment. Keyboard paired with two dongles on different computers. What happens when you are using one computer and the other is also getting the keyboard input? Nightmare, maybe I'll wake up in a moment... :o :shock: :? :(
Signature retired

humbug
Posts: 11
Joined: Thu Jun 06, 2013 11:42 pm

Re: Issues with the K400 keyboard

Tue Oct 22, 2019 11:20 am

Please ignore my comments reference not needing to pair - I was not aware that if the keyboard was paired with another dongle it lost is pairing with the original but as a result of HawaiianPi's reply I decided to consult the Logitech guidance and now am much enlightened.
Sorry if I caused confusion.

John

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HawaiianPi
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Re: Issues with the K400 keyboard

Fri Oct 25, 2019 2:37 am

davidcoton wrote:
Tue Oct 22, 2019 10:07 am
Think about that for a moment. Keyboard paired with two dongles on different computers...
Yes, I certainly understand why Logitech didn't allow it (although it could be fun, just to mess with someone :twisted: ).

I had a specific and likely unusual use-case in mind. I had both my K400r Keyboard and an M510 mouse paired to the K400r's dongle, because I prefer a mouse to a trackpad. However, that mouse is also the one I grab when I'm taking my laptop somewhere, and it would be nice if I could just pop the dongle out of the mouse (it stores one inside by the battery) and use it without the extra pairing hassle.

Both dongles would never be in use at the same time.

But alas, it's not possible, so I either need another mouse, or put up with the double-pairing hassle when that scenario arises (pair it to the mouse when I'm elsewhere with my laptop, and then re-pair it to the keyboard when I'm back at home). Not a huge hassle, but still...
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?

jhickie
Posts: 3
Joined: Thu Oct 17, 2019 9:16 pm

Re: Issues with the K400 keyboard

Mon Oct 28, 2019 4:45 pm

I finally got it working! Thank you all so much for your assistance.

Apparently, it was my own firmware (in my head) that needed updating, in addition to the device's. I had no idea that the pairing information was stored on the dongle and device, not the computer. Turns out I have 3 Logitech dongles.. I completely forgot I have an additional one for a game controller.

So I plugged each dongle into my computer with the Unifying Software installed and had a look at what was paired. I saw some old devices and removed them, found the dongle with the K400 pairing information, updated the firmware, repaired it and plugged it into the RPi, and bingo!

Linux is new for me so this was a learning project to begin with, I just didn't expect to get derailed by my keyboard! Now I can get back to learning more about the command line interface and language. Got everything configured in Raspbian, ran KODI and got that all setup, really enjoying it.

Thanks again for the help everyone!

RossDv8
Posts: 159
Joined: Thu Jan 21, 2016 12:35 pm

Re: Issues with the K400 keyboard

Sat Nov 09, 2019 10:45 pm

If you ever use the k400 series keyboards and rodents with the Pi 4 from a distance, for example, as a multimedia centres while sitting in a comfy chair across the room, and the mouse cursor (or trackpad on the k400r) is messing up. I found the k400, especially the k400r is very sensitive to direction and distance from the Pi 4.

Putting the dongle on a short (about 150mm or so) good quality shielded cable (shielded ones are usually a bit thicker) and having the flat end of the dongle towards the keyboard helps, especially if you are sitting 2 - 3 metres from the Pi.

The other thing I noticed is that as soon as the batteries in the keyboard (or mouse) begin to lose charge, the cursor can do weird stuff. Like lag or freeze, and typing letters can delay, then a heap of what you typed will suddenly appear at once.

My solution was to switch to those outrageously expensive AA (for the keyboard) and AAA (for the rat) silver 'Lithium' batteries. I use Eveready, but I'm sure there are others. The price is worth it, because they last so much longer and maintain steady performance that they are worth the cost.

I no longer bother with rechargeable NiMh batteries in keyboards and mices because even the best ones, at 1.2V per cell, don;t seem to handle the distance well for my multimedia Pi 4 applications. It is nice to recharge and try to save the planet, but a nice fresh set of 1.5V cells are much more reliable that 1.2V.

(Just my thoughts on some 'other' issues with the k400 series keyboards..)
Pi 4B 4GB - system on WD 240G SSD ( but /boot on Sandisk microSD)

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