Ketra Lighting

[Jeff]

I recently had the opportunity to test Ketra lighting with Loxone and thought I would post my findings here in the case someone else is interested in integrating Ketra with Loxone. 

Ketra is a communicating LED bulb with a hub. What makes it unique is the quality of the light and that each bulb has its own sensor to sample the actual light output to ensure the desired color is the color it actually outputs. Compared the LiFx bulbs I also have, the Ketra is noticeably superior. 

In my case, I used their N4 hub to interface with Loxone. The N4 hub has a wired ethernet port and uses a proprietary implementation of zigbee to talk to each bulb. The N4 hub has a local RESTul JSON API, but by default its restricted to HTTPS only. After a call to Ketra tech support, they explained the not so obvious method of allowing HTTP. In short, update to the latest firmware and enable telnet on the N4 hub. 

Once HTTP is enabled, then interfacing with Loxone is just a matter of setting up Virtual Outputs. I won't go into details about that as its no different than many other Virtual Output integrations. Currently the bulb is configured as an output to a lighting controller block, using 0-100% dimming and scaling the output to match the Ketra API. I'm calculating the desired CCT once per minute (warmer in the morning, cooling as the day approaches noon, and warming in the evenings) and updating the CCT via a Virtual Output separate from the lighting controller. 

Other than the HTTPS issue, the other hiccup is the full color range. While Loxone uses the RGB color space, Ketra uses the XYZ color space. Ketra provided a formula to convert RGB to XYZ. I have not yet implement this. 

So far, this integration has been rock solid even though the bulbs are wireless. 

[Andrew B]

Wow, somebody actually used XYZ in a product? I’ve never actually seen it in the wild before!

[tkn]

Why didn't you use a DMX interface?

I have a ton of Ketra I am planning on using in any screw in fixtures. California doesn't allow screw in recessed so I will probably end up selling a ton of the A20 bulbs.

[Jeff]

The vendor pushed the N4 hub, which will give you much more control than the DMX interface. That said, I'm not sure the added control is significant in practical application. Once I got over the HTTPS issue, I've had no problem controlling the lights. I did have some response time delay (reminiscent of the old response X10 delay, when you push a button it takes a noticeable moment for the light to active). That ended up being the result of sending multiple simultaneous HTTP commands via separate virtual outputs (because Loxone only passes one variable to the output.) Once I straightened that out, all seems well so far. 

Here's the API for the Ketra N4:

https://s3.amazonaws.com/ketra-software/KetraMobileAPI/v1/dist/index.html

[tkn]

I think I have a couple of N3s I picked off of eBay. I also have a couple of the touchscreen switches somewhere.

I need to figure out what else I need but I'll probably have a bunch of Ketra stuff for sale soon.

[Jeff]

Appears the N3 is required for linear lights, and it can communicate with either DMX or the N4 Hub. Not sure if the N3 communicate with their bulbs

[Brad]

In my quest to find affordable RGBW recessed lighting these are starting to become an option I'm willing to explore. What are your thoughts on this system after some more time with it? How would you describe the control latency in your API implementation vs a dmx version. I am wanting to do under cabinet lighting and cove ceiling lighting in some parts of my house and was considering LV DMX RBGW tape for these applications. Does ketra have a solution for these applications? If I have to get the dmx infrastructure in place to do the tape would you consider the N3 instead of the N4?

[Jeff]

There is little to no noticeable latency. However, after Lutron bought out Ketra, it is my understanding they disabled the ability for new installations to integrate with third party controllers; existing installations are grandfathered. In other words, new Ketra bulbs will only integrate with Lutron controllers. I have no experience with the DMX integration or know if it is still an option. Ketra does not have a tape light. 

Philips Hue is similar, in that it has a hub that talks with their bulbs via zigbee. They also have a lot more bulb form factors, including a tape light, and is more readily available. I picked up a hub and a couple bulbs recently. The integration is very similar. So far, Hue has worked reliably. I haven't set-up a good comparison for the quality of the light just yet, but I can tell the Hue doesn't perform quite as well in the more amber colors. 

You can run DMX over cat5e cable. If you're not sure what direction to go, consider running the cat5e cable just in case. I did that in a few places, but haven't bothered to connect any of it yet. I may pick-up a Hue light tape for testing before long. 

[Brad]

Did they disable the API or something? I wasn't desiring to connect the system to the internet. Do you know if the same limitations were imposed for the "commercial" versions as well?

Part of the reason I am still leaning ketra (if I can still make it work) is to get wet location versions. The hue versions don't appear to have an appropriate version for soffit lights and I get concerns about signal strength unless I want to put hue bridges everywhere (I don't). Another behavior that I need to avoid is the fact that hue bulbs (and other smart bulbs) default to on when there is a power blink. It would get very annoying very quickly if this were to happen in the night. Do ketra bulbs or fixtures do this?

[BartVB]

Regarding Philips Hue; the bulbs don't need to connect to the bridge directly. They all form a Zigbee network (mesh) through your house. You won't need to add additional bridges, but for reliable connections it helps to have more bulbs/strips.

One of the main annoyances of Hue was that they indeed defaulted to fully on after losing power. They finally fixed that a few months ago. Currently you can choose whether they default to that behaviour or they will return to their last state (which can be off) after power has been cut.

My main reason for trying to avoid Hue is the fact that it's wireless (which is inherently less reliable) and because running LEDs on 230V in so little space is rather inefficient. But for retrofitting they are really nice and so far very reliable. I've been using Hue in my current home without any significant problems. Main problem with reliability is with the Hue dimmer switches. They tend to temporarily lose connection with the bridge one in a while. Extremely annoying. Haven't had connection or reliability issues with the bulbs in 3 years time.

[Jeff]

Did they disable the API or something?  I wasn't desiring to connect the system to the internet.  

The Ketra N4 hub has a local, restful API and a telnet interface. In short, with the restful API you set-up a virtual output in lox that points to the LAN IP address of the N4 hub. Then, issue a jason formatted string to set the state of the bulb / bulb group. Internet connection is not used. As I understand it, the latest firmware for the N4 hub disables the restful API in new installations. Lutron controllers use the telnet interface. I presume that one could still use the telnet interface, but IDK.... maybe someone more familiar with Lutron controller protocols could chime in here?

Do you know if the same limitations were imposed for the "commercial" versions as well?

Prior to the Lutron acquisition, Ketra tech support was impressively helpful. When I first heard that Lutron had disabled third party interfaces, I called their tech support and was told the CM (commercial) version still supported it but the HW (Homeworks Residential) did not. My dealer then told me that only existing Ketra customers can get the CM version but Lutron would not provide any technical support. I called back to Ketra tech support, and this time they acted like they had never heard of the restful API; even though I called the same number, the experience was like I talked with a generic Lutron support tech who wasn't familiar with the product. My guess is Lutron relies on their dealer / installers to provide customer support, and those installers are trained to use the Lutron telnet protocol. Perhaps try calling yourself and see what you can find out. A major advantage of Hue is you don't have to deal with installers or antiqued protocols.

I can't speak to signal strength of the Hue system just yet, but Ketra and Hue both use a Zigbee mesh. Both have a limit on the number of devices per hub. For Ketra, it is 49 bulbs to one hub. I think Hue is slightly more (I've heard 50 to 63 bulbs per hub.)

Hue appears to have outdoor rated bulbs (see their website.)