The Velleman K8062 story

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mcallegari
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Real Name: Massimo Callegari
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The Velleman K8062 story

Postby mcallegari » Sun Mar 06, 2016 12:51 pm

I'm afraid I need to say that this is not a happy ending story... :(

This is the device I'm going to talk about (link to the device page)

K8062.png


After a few feedbacks from users trying to use it with QLC+ (without success), I decided to buy one.
I have always been skeptical that a so old device had a cost ranging around 100-120€ and recently I found it for just 68€. I thought that was a bargain and with my big surprise...I bought a kit !
Basically the box included a naked PCB and separate components, so I literally had to solder them all to assemble the device. Luckily, even with my limited soldering skills, the device worked the first time.

QLC+ always claimed to support the device on Windows, so I started from there...and after a few minutes I realized how many troubles this device brings.
To understand what I am talking about, please read this page from the OLA wiki.

Basically there are 2 revisions of the same kit (K8062) and the first revision was definitely not suitable for a reliable DMX transmission (512 channels @ 44Hz)

Now the troubles:
- first of all there is no way for QLC+ to understand the revision of the Velleman device
- the above is caused by a very bad design of the Windows driver. Basically the K8062 is supposed to be a HID interface, but it's not. It uses two software components to work: a DLL file (K8062D.dll) which is the QLC+ interface, and a binary exe file (K8062e.exe) where Velleman stores all the big secrets to communicate with the hardware.
Unfortunately the exe file is close source and I don't have the sources of the DLL file either. :(
Basically the exe file is a daemon that is started when the DLL requests to communicate with the device. In fact, when you activate the DMX output in QLC+, you will see something flashing on the screen for a fraction of second. That's the exe file starting up and as far as I understood, it implements some DMA transfers, most likely through another DLL called FASTTime32.dll.
- when you plug a K8062 on Windows for the first time, all the above 3 things are automatically installed in your system (2 DLLs and the EXE). Problem is that Windows developers think that the whole world use Microsoft tools to develop, and this is not the QLC+ case (I use MSYS2) so QLC+ is not compatible with the DLL provided by Windows out of the box. That's why if you intend to use a K8062 with QLC+, you need to copy a modified version of K8062D.dll to the main QLC+ folder
- furthermore, starting/stopping the device is very unstable. Sometimes the EXE daemon gets stuck and you might find 2 instances of it running at the same time, which means the device will not work

Conclusions:
- in general, my personal suggestion is: stay away from this device
- if you bought the K8062 many years ago, it's not guaranteed to work with QLC+
- after some tweaks, I restored the support of the adapter in QLC+ 4.10.3 (screenshot below), but I'm not quite happy about it
- Linux/OSX support would be possible, but after seeing how badly the device works, I'm not convinced that the effort it worth it
- for the same price, you can find much better DMX adapters, fully supported by QLC+ and where the manufacturers are more open to the open source world

K8062.png
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boxy
Posts: 303
Joined: Tue Apr 21, 2015 8:18 am
Real Name: Robert Box

Re: The Velleman K8062 story

Postby boxy » Tue Mar 08, 2016 2:07 pm

Wow. Followed the link and that thing really is a piece of overpriced crap. And you have to make it yourself!

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