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Offline voice control on trial: what can PRATGLAD do?

ProKNX would like to introduce you to Frank-Oliver Grün, the well-respected technology blogger of the German language site DigitalZimmer. He recently tested our new PRATGLAD smart assistant that works with offline voice control, and wrote an in-depth review of his findings.  He has been kind enough to let us translate his article, which you can read below.  You can read the original German article here.


By Frank-Oliver Grün

I have already written about the launch of PRATGLAD on my blog. This small box, in the format 81 × 81 x 46 mm, does something that users of digital assistants can normally only dream of: offline voice control with no need for the Internet. There is no cloud to which the PRATGLAD needs to send its microphone recordings in order to have them processed online – nor to receive a machine-readable translation back from there. According to the manufacturer, ProKNX, the device processes voice commands locally.

Or, as the company puts it: “What’s said at home stays at home”.

The lack of needing the cloud to function makes the many discussions about data protection superfluous: whether employees of the provider might analyze recordings to determine the quality to improve speech recognition, or whether someone is listening in unnoticed because the assistant has accidentally activated itself.

Requirement for operation: an installed Trådfri system with Ikea gateway. ©digitalzimmer

Many smart home owners would be happy to have a discreet and data-saving alternative to Alexa or Google Assistant. However, I have to dampen your enthusiasm right away: PRATGLAD does not work everywhere. For those users with IKEA Smart Home products and a Trådfri gateway installed at home can use the autonomous assistant. It sells for 399 euros directly from manufacturer’s online shop (LINK). A starter package for smart home novices costs 499 euros. In addition to the PRATGLAD unit, the package also contains the Trådfri gateway, an E27 lamp and a wall switch.

Setting up PRATGLAD – this is how it works

From the moment of unpacking, it is noticeable that it is not a smart speaker in the conventional sense. The connection to the home network does not take place via WLAN. PRATGLAD connects to the router via LAN cable, unlike an Amazon Echo or Apple HomePod – and its approximately 1.90 meter long network cable also supplies it with power.

A PoE adapter supplies the PRATGLAD with power and connects it to the home network. ©digitalzimmer

Power over Ethernet(PoE) is the name of this process. The professional sector widely uses PoE. It has the advantage that PoE devices do not require an additional power connection. However, there are also LAN centers – so-called switches – which feed a voltage into the computer network. This is usually not the case in private households. Therefore, the PRATGLAD kit includes a small PoE injector. The black box connects to the 230-volt network with a Schuko plug and comes with its LAN sockets between the router and the voicebox (pictured above). It injects the necessary voltage to the assistant, in the same way a perfusion provides a person with medicine or nutrients. Hence, the name ‘injector’.

The housing with ribbon cable is suitable for wall mounting ©digitalzimmer

Thanks to the almost two metre long LAN cable connected to Pratglad, the PoE power supply can be hidden quite easily, e.g. behind a cupboard or under a sofa. A thin ribbon cable, only 8 mm wide and 2.5 mm thick, then leads to the loudspeaker. A WLAN connection would still be nice and also more practical in many apartments, because then only a socket would be needed and not an additional LAN connection near the injector.

After connecting, you need to wait until the offline voice control assistant has started, and booted up. The boot-up process takes one to two minutes. In the meantime, open a browser window on your computer and enter the address Smartphones or tablets are just as suitable for this. The only need for this stage is an online connection to the Internet, otherwise the further set-up will not be possible.

The PRATGLAD voice assistant is set up in the browser. ©digitalzimmer

In order for the browser to find Pratglad in the network at home, it needs the address range of the router. With a Fritzbox from AVM it starts with 192.168.178 by default, the Telekom uses 192.168.2 in its Speedport models, Netgear uses 192.168.1. However, it can also be a completely different sequence. After entering the range, the complete IP address that the router has assigned the voice assistant will appear in the network. In my case it was

After entering the router address range, the search will find the PRATGLAD. ©digitalzimmer

A click on the linked IP address leads to the actual configuration page of the offline wizard. This browser window is where all other settings are configured. Compared to the app-guided installation of other voice assistants, this seems a little cumbersome. On the other hand, it has the advantage that no program has to be downloaded. Also, later on you rarely need the configuration page anyway, except if you need to change the settings.

Configuration of the offline voice control assistant

The developers have clearly summarized what needs to be done on one screen. The first four installation points will already be checked. The connection to the Trådfri gateway now follows. This requires the 16-digit security key that Ikea prints on the back of the gateway.

The PRATGLAD box can only access an IKEA gateway with this letter and number code. The connection status changes to green with the correct code entry, and the set-up continues to point 3: Room name, speech volume, and sensitivity. At this point, you choose which room in your home PRATGLAD is assigned to. The “light off” command then act on smart devices, e.g. lamps and sockets, in the same room – without having to specify the location. However, a naming distinction is important when using several devices. In addition, ProKNX offers Pratglad satellites for 299 euros each.

In my experience, the volume can remain at maximum. Compared to an Amazon Echo or HomePod mini, PRATGLAD’s voice sounds quite subdued. You should not expect a large volume of sound either. The loudspeaker behind the silver metal grill is designed purely for voice output. It does not play music or alarm tones.

Point 4 of the configuration allows the choice between online and offline speech synthesis. The setting applies to responses from Pratglad. If asked, the box announces the time, or reports the status of devices – whether lamps are switched on or blinds are open or closed. An online voice is set on the device before leaving the factory. It uses the Amazon service Polly (LINK).

Strictly speaking, this brings a cloud service back into the house. However, Polly receives no audio recordings. Unlike its Amazon sister Alexa, it works as a pure text-to-speech (TTS) application. That means that Pratglad sends a text file to the server and receives an audio file back with the spoken version. However, this can contain status information from the apartment, such as which lamps are currently switched on or the percentage that the blinds are open.

In any case, if you want to keep this information private you can remain offline. In this offline voice control situation; PRATGLAD does the speech synthesis locally with its 32-bit microprocessor. You can have maximum data protection in exchange for a machine voice that sounds a bit like one in old science fiction films. The robotic voice cannot be changed, but if Polly is used, it provides two female voices (Marlene and Vicki) and one male voice (Hans). Here are sound recordings of the four voice variants, recorded with the iPhone directly on the speaker:

Snips’ offline voice – sounds a little like a robot.
Here is the online version Vicki – supplied by Amazon Polly.
Marlene from Amazon Polly – somehow reminds of Anne Will.
The online voice of Hans – if you’d rather hear a man.

For users of the Symfonisk speakers from Ikea or owner of a Sonos multiroom system s the online version has another advantage: Polly’s voice feedback can take place on a Symfonisk or Sonos device in the same room. Amplified in this way, the voice sounds a lot better than it does from the small PRATGLAD loudspeaker. In this case however, it is necessary to mute the voice output on the device. The external speaker lags behind the internal one, causing echoes.

PRATGLAD can use IKEA loudspeakers such as the SYMFONISK for speech reproduction. ©digitalzimmer

Other than that, there is not much to set up. Pratglad automatically takes over the rooms and installed devices from the Trådfri gateway. Room names on the Sonos app must correspond with the names on the IKEA gateway when Symfonisk or Sonos loudspeakers are also involved in the set-up. You will discover that if the names are different, the voice control cannot assign them to a device.

You can train PRATGLAD to understand device or room names that are added later. The button under point 5 on the configuration page does this. The list of learned designations can contain up to a maximum of 100 entries. That sounds like a lot, but it can be exhausted very quickly if the option “Symfonisk / Sonos favorites” is clicked. This causes Pratglad to get all playlists, radio stations and podcasts into its system. In my case, this meant that half of the memory was already full.

“Hey Snips …” – offline voice control in action

One thing should be clear from the start: Pratglad is not a digital assistant like Amazon Alexa or Siri from Apple. You cannot ask it about the weather, keep shopping lists, or have it tell you jokes. When searching for Wikipedia terms, it has no answer. The only task the little helper does is to control connected devices using voice commands.

When PRATGLAD is listening, a blue LED lights up behind the front grille. It can be switched off. ©digitalzimmer

The wake word for this is “Hey Snips” – because PRATGLAD is based on the language platform of the same name, which is now part of Sonos (LINK). The syntax is largely similar to that of online wizards. Standardized voice commands work like “Hey Snips …”

  • “… turn on the lights everywhere”
  • “… dim the ceiling light to 50 percent”
  • “… close the blind in the bedroom”
  • “… play Deutschlandradio in the kitchen”
  • “… louder in the living room”
  • “… stop music”

In addition, questions about the device status are possible:

  • “… what is the status of the roller blind in the bathroom?”
  • “… is the light in the hallway switched on?”
  • “… which title is currently playing?”

Experience shows that clear names are important. The more the names differ, the easier it is for a digital assistant to control. This also applies to Snips – especially when it plays music or when English titles are involved. In the test, the German-speaking PRATGLAD occasionally had problems playing the “Party” playlist from my Sonos system. I found that it played the list with the name “Dinner” best.

If requested, a log shows what PRATGLAD understood and responded to. ©digitalzimmer

Web radio station retrieval also ran into some issues. “Deutschlandradio” caused few problems, but on the other hand “SWR 1” did. Strangely enough, “EgoFM” always worked. Renaming favorites in the Sonos app sometimes improves the recognition rate. However, this does not automatically help. Accurate music selection is one of the most difficult achievements of all language assistants – that is where we discover the limits of  Alexa etc.

The offline voice assistant, on the other hand, reliably handles everyday programs with play and pause, louder and quieter. So that it can understand commands better, Pratglad mutes a connected Symfonisk or Sonos loudspeaker in the room as soon as the activation word (“Hey Snips”) sounds. The music restarts after PRATGLAD performs the requested task. Two integrated microphones also pick up commands said from the other end of the room – or through an open door from the neighboring room. Not quite as senstive as my third generation Echo Dot but sensitive enough.

There were no incorrect activations in the test, or at least, I did not notice any. It would not matter anyway, as PRATGLAD does not transmit audio recordings to the Internet; not even mistakenly registered speech. The manufacturer ProKNX recommends pausing for a moment after the activation word, and only then giving the actual voice command. The control of lamps, sockets or roller blinds really work without any problems.

PRATGLAD already supports the new scene function in IKEA’s home smart app introduced by IKEA at the end of November 2020. Therefore, app-defined scenarios can be addressed directly using their names. In addition, on the PRATGLAD configuration page there are so-called super scenes for “Good morning”, “Good night”, “I’m at home”, and “I’m leaving the house”. Up to three voice commands can be stored for each command, which are automatically executed when nominated – which can even change in relation to the time of day, if desired.

Conclusion: data protection has its price

Offline voice assistants are not an off-the-shelf product. Until now, anyone who wants to do without the Internet has had to bring a lot of time and technical enthusiasm to the table. With these qualities, the user can then build a corresponding solution themselves using a Raspberry Pi minicomputer. As a good example of this, blogger colleague Felix Schwenzel did this with Snips when the code was still freely available as an open source project (LINK).

ProKNX does this work for buyers of a Pratglad. Admittedly, the commissioning of smart speakers with Alexa, Siri or Google Assistant is smoother. The external power supply unit with PoE injector is not for everyone. However, the step-by-step instructions in the browser explain the installation process so simply that even computer laypeople can handle it. Smooth functionality positively offsets small issues with the music control. Above all: PRATGLAD protects your data, and works with offline voice even if the Internet fails. Everyone must decide for themselves whether this additional security is worth 400 euros. Price-sensitive IKEA customers, who spend only 10 to 20 euros on a smart home product may be more reluctant to invest in an assistant like this.

In companies, or in the home office, these one-off costs do not play such a big role when it comes down to discretion. If you do not really trust US corporations and their online assistants, you finally have an alternative with PRATGLAD. As an additional bonus, it even comes from Europe: ProKNX’s headquarters are in southern France – near Antibes on the Côte d’Azur.