Whole house intercom

I just got my rough in inspection yesterday so my house is moving along, but before I close up the walls there is one more thing I am thinking about and that is whole house intercom. I started looking at HTD Lync 12, but my concern is that it’s going to be out dated fairly quickly. So my next thought was to go with POE Android tablets in every room. On the hardware side that actually costs less, but I am struggling with the software side.

On the software side I could just use a VoIP client like bria, or even one of the dozens of intercom apps out there, but I am looking for something more tightly integrated into OpenHab. How hard would it be to modify HABDroid to add intercom functionality? Anyone know of a programmer I could hire to do that work?

I am skeptical that this would be easy. I believe the current model for HABDroid is REST and even then it is a Pull, not a Push. This would require adding not only the ability to push data to it, but also implementing some sort of VoIP.

Obviously all things are possible but I suspect there might be better ways. Since you are talking about HABDroid I assume you are looking at Android Tablets. I did a quick Google search and it looks like this is doable using Tasker and Hangouts.


I’m sure there are other alternatives as well. The key though is Tasker. You can think of Tasker as being like an openHAB server for your phone. It is all about automation and there are plugins for almost everything. I myself just added an MQTT plugin so I can send MQTT messages to my broker which OH picks up. It also supports REST so you can interact with that. In fact, with the AutoInput plugin you can have Tasker simulate presses on the screen which lets you control pretty much anything on your phone, even those things that don’t have Tasker plugins.

This approach would take a lot of time and effort but I think it would be far less effort to find an Intercom system that integrates with Tasker (or use AutoInput to launch and connect to an Intercom system that doesn’t support Tasker) than it would be to add VoIP to HABDroid.

That’s my two cents anyway.

Others, including the HABDroid developers may know more.

I have a Lync12 and have not found the intercom functionality to be very useful. For one, the zone or zones you want to talk to you must be on already. The user interface is also a bit unintuitive.

The serial control interface doesn’t expose any of the intercom functionality either. Though it is fairly straightforward to turn zones on and off and the like. (I am actually in the process of writing a Lync to MQTT bridge you might find useful: https://github.com/TheOriginalAndrobot/htd2mqtt)

Thanks, I will look into Tasker, thanks.

I’ve never used these, and I have no idea if/how they would integrate with openHAB, but I heard about the Nucleus wifi video intercoms the other day and they sounded pretty neat.

Its interesting, but very very buggy, I ended up sending mine back and buying android PoE tablets. They also are very closed.

Hmm, I had no idea that Android tablets with PoE was an option. A google search turned up a few options, but they seemed fairly expensive to me, plus I’d worry about getting security updates in a timely manner. Most of the ones that I looked at claimed to be running some variant of Android 4.x so are probably chock-full of known security bugs. The Nucleus intercoms are too expensive for me right now too but I liked the fact that the camera had a physical shutter that can cover the camera.

Plus the fact that my house isn’t really big enough to require intercoms…

The US guys are just reselling the China guys with huge markup. Check out Alibaba for “Android PoE Tablet” you will find a lot of options for under $200. I ended up going with:


A good set of firewall rules can mitigate this risk. Since this would be a special purpose tablet with a set use case it should be pretty easy to only allow certain types of traffic out to the Internet. Besides, the biggest risk for tablets comes from installing apps and ads so by not allowing browsing on the device and vetting the apps that get installed to avoid ads the risk could be mitigated to the point of being pretty small.

Obviously something that can receive updates would be better, but I wouldn’t discount these for use out of hand. And some may support alternative OS such as Cyanogen.

Yeah, it’s true that firewall rules can help with security, but it’s also more than that. Eventually, the apps that I’d want to run will start requiring a newer version of Android, or there’s a bug or something else. I have no confidence that some random Chinese manufacturer is going to issue an update, and the chances of Cyanogen or someone else picking up support is unlikely unless the specific device is wildly popular. I’d rather start out with something that I know will receive updates in a timely manner.

I have played with a few options and so far none of them look very promising. The wife would like to be able to page all rooms and most everything I have found so far only allows for 1:1 conversations. I also have tried a few broadcast methods, but there is quite a lot of delay between stations making the announcement sound bad. I think the solution is to build something based on IP RTP multicast. Looking for an android developer now, will follow back if I get anywhere.

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One option for paging would be to design something similar to what they use at the department stores - you speak, hang up, it broadcasts directly afterwards. Would be a lot easier to design that than a real time broadcast. I’ve considered something similar for our house.

Really interested to see what you end up with.

Turns out IP Multicast only works on some Android devices, however I found a trick around that. You can simply send to the local broadcast address such as:

./ffmpeg -re -i /test.mp3 -vn -acodec pcm_mulaw -ac 1 -ar 8k -f rtp udp://

That will play a test announcement to every tablet in the house and since it’s broadcast they are now in almost perfect sync. Now I need to I guess just write a script that wraps PlaySound and say so I can broadcast them out with ffmpeg.

What app are you using on the Android side?

Right now I am using rtpspk, however I am paying a android developer to write an app that does the same thing, but is more intercom focused. It will have a talk button and a DnD button and will mute local when speaking.


Did you ever get your app developed? Is is working well? would you consider selling the source code?