Hardware selection for beginner

Hi guys, hope it’s ok to start a new topic for me, I don’t want to hijack someone else topic.

To start simple, I want to start automating my home, and I’m a student so money is tight.
For the moment, and due to financial considerations I just want to start with heating. And just to make sure I am planing to start with 1 radiator and then extend to 3 or more.
Right now I’m using some digital TRV (cheap 15 euros ones from lidl) and last winter they saved me 200euros on the heating bill :smile:, that for me is a good reason to want some automation. Right now I have one in the living room and one in the bedroom. in the bathroom and hallway I still have mechanical ones.

What is mostly annoying for me is that I have to decided on a weekly schedule and stick to it or play with them on a daily basis. That is not fun as sometimes I get home late and they’ve started heating 3 hours in advance or even more.

That being said I looked around and decided that openHAB will suite me on the software side (at least for the beginning) as it offers a web gateway. I am sharing the public IP with a bunch of people and I can’t get direct access to my home router in any way (tried that), this is solved by my.openHAB form my understanding. which is nice…

Going on. As I mentioned, I only want to start with heating of one radiator (the bathroom one) so I can save some more money and at the same time learn openHAB.

I have a raspberry pi unused which I plan to use as a server. Planned to use it for OSMC but don’t need it for the moment.
As a student I was looking for the MAX! TRV.
my plan was to buy I cube and a TRV, a door contact and a eco/auto button as a test platform. But then I realized that the guys at ELV sell a bunch of automation stuff with different protocols, so I got stuck.

In the end I would like to have, for starters, door/window sensors (to stop the heat while they are opened), TRV valve to control the temperature in the room and in the end to be able to add other automation like window blinds and lights.
I would love to pair it with IFTTT and to be able to control it remotely from my phone and at the same time even have a button by the door for those times when I need to run out and don’t have time to go into the app and set the temperature in eco mode.

Now my biggest question problem si hardare, as I would like it to somehow be future proof but not to spend a lot of money on it.
Should I choose the MAX! with the cube or with the USB dongle? (max with cube is within budget)
Will the dongle work with the rPi?
Should I choose other other protocol like homematic, devolo (z-wave), RWE smarthome?
I would prefer something easily to source in europe (preferably DK/DE).

Thank you for the help guys :slight_smile:

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I can’t help with hardware advice. I’m in the US so my advice probably wouldn’t work for you anyway. But do have some info.

You are on the right track with wanting to start small. I would get the heater working by itself first and then expand into the door and window sensors and such.

When using my.openhab, you can activate an IFTTT channel and create recipes to control your switches quite well. However, I’ve noticed some delay for certain actions.

I set mine up to know when I’m home or not. I use Network Health to ping my and my wife’s phone as well as bluetooth scanning to see if the phones are nearby.

Thanks for the feedback. I will have to order a few things at a time as shipping is almost 3/4 the price of a heater… And I would like windows sensors to detect when I’m airing the room, in order not to try and heat the outside :)))

the idea is that the cube is around 50 euros. Same as the CUL.
one heater valve is around 40 euros.

Now I have no idea how more complicated the z-wave can be and how it works with the Rpi, but their prices are around 10-20 euros more.

I really don’t want to invest into the MAX! and then one year later discover that in order to expand I should of gone for the z-wave… on the other hand I really don’t want to throw a lot of money at it from the beginning and realize it doesn’t suite me, and it’s harder than expected to make it work.

Thanks for the idea to use the phone network connection to detect presence, but sometimes my internet sucks and my phone switches to LTE for days as I have good coverage and more data than I could even use (20+Gbs)

I was really hoping there would be more activity on this forum :disappointed:

I’ve some z-wave in my system and I’m very happy with its performance and ease of setup. Not everything is supported (e.g. color commands on lights in OH1, certain devices) but it is an incredibly popular technology used by tons of people. The Aeon Tech zwave dongles work just fine on a RasPi. I’ve never heard of MAX! before now so have no opinion on it.

Similar problem with my wife’s wifi, which is why I also scan for bluetooth to detect presence. It is a bit redundant but I know when nothing is showing the phone is there, that person is almost certainly not home.

First, give it time.

Second, this is an openHAB forum, not a MAX! or generic Home Automation forum. Thus you have a group of people who know a lot about openHAB, a smaller subset that know a lot about a set of bindings, and a really small set that knows a lot about any given technology. As long as I’ve been using openHAB and contributing to these forums I’ve never heard of MAX!, though I do see it listed there on the wiki as a supported binding. Post an openHAB problem and people will be all over it. But post a technology specific question like this and the audience of people who can help has dropped drastically. In other words, this might not be the best forum to help you choose.

But realize this, Home Automation is a journey. You will spend some time and some money trying to get things working that will fail. You are doing the right thing by doing due diligence before diving in but don’t think you will come away with the perfect answer.

Finally, look at some of the other more generic home automation forums, or MAX! specific forums. There might be more people with experience with the specific technology to help.

You can do that pretty cheap with an ESP8266 and a simple magnet switch to mount on the window frame.

£4.17 http://www.ebay.co.uk/itm/311451344588
£0.99 http://www.ebay.co.uk/itm/291490269679
£1.91 http://www.ebay.co.uk/itm/191348603397
Total: £7,07 which is just under €10 :smile:

The NodeMCU development board could be replaced by an even cheaper module, but then you would need to figure out how to do the 3.3v it needs, and also get something to program it with. The development board can be powered directly from 5v usb, and be programmed through the same.


Hi Mikey, I’m looking to implement this solution myself. Are there any relative-beginners guides that will help me set this up (programming etc?)

I’ve got the basics of GPIO hardware with the RPi, but not worked with anything like the ESP8266.


I can make a guide this weekend, but it is pretty straight forward to do.

Hi Rich,

I’ve seen MAX! used a lot, since it’s cheap… I know it’s limitations, what I wanted to know more is if I should pick something like zwave or I should go with something more obscure like the MAX!

I’m inclining more and more towards zwave.
Can anyone recommend some heater valves which work over zwave, are reliable and also allow you to set the temperature from the heater directly? :smile:

Would it be a problem for the rPi if I would have a mix of different protocols?
MAX! is still dirty cheap compared to others, and I was considering using that for heating and in the future to add lights and socket control using other protocols like z-wave.

Anyhow, thank you all for the fast replies :smile:

Here is my take on trying to explain how to make a switch to monitor a door or window.

Shouldn’t be a problem. Handling multiple technologies is one of the raison d’etre of openHAB. So long as you don’t fill up all of your USB ports (in which case you will need a hub) it should work. I myself have MQTT, zwave, Nest, Yahoo weather, NTP, and some HTTP stuff all mixed in my setup and it works great.


I am new to this - a question - can you in your solution add several reed switches to the same board and give each reed switch different device ids ?

and then for example with 4 reed switches be able to detect 2 windows, the door and if door is locked or not?

How many reed switches can you connect to the board?

In theory you can connect up to 10 switches to it, but that is not something I have tried.

You can add another id to each switch.

The /home/living/esp10/state syntax I decided on is not limited in any way, and could easily be /home/living/esp10/switch1/state or /home/living/esp10/switch2/state or something completely different, as long as the item in openHAB just matches the same combination, everything should work. :smile:

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Hello emanuel,

why you want to use MAX! while its closed system. And eventually you have to pay for it.
I was thinking to make something like this:

It includes:

  • Heating valves (24 VAC or 230 VAC ~2W NC, controlled by ON/OFF signal)
  • 1wire temperature sensors for radiators (detects when its too hot and disable heating logics)
  • 1wire air temperature sensors (hidden in the lighting switch, its used for controlling heat valves)
  • Some relay block which can be controlled with Rpi
  • Rpi with OpenHab, to set timers and logics for the setup, control with phone

Now the open questions are:

  1. Can 1 wire be connected in topology star? How does cable length is limited in this case?
  2. Should GPIO4 pin or some dongle/i2C converter be used for 1wire sensors?
  3. Heating valves should be NC (normally closed)? If OpenHab will break/stop working valves will be closed (no temperature will flow to radiator).
  4. Is there posibility in OpenHab to set up logics:
    4.1. Control valves by 1 wire temperature sensors with 15 minute different duty cycles
    4.2. Block logics of radiator while its too hot
    4.3. see charts and history of temperature values
    4.4. set up logics for night, eco, comfort scenes

Hi guys,

Rich, thanks for the reply.

Max! is free for the first 3 years and afterwards you would pay 1-2 euros/month if I remember correctly. But this fees are required only if you would like to use their online services. If I use openhab, even with the cube, I don’t have to pay anything. Right now I can use the CUL directly with openhab, but if I want to use all the accessories (windows contact, etc) I have to use the homegear binding. I’m still investigating.

If I go for z-wave. The rPi interface would cost similar (50 euros). A thermostat for MAX! cost 30 euros, one for z-wave would cost at least 40-50 euros (I found the danfoss ones for approx 40 euros in Poland). But since most z-wave ones which can also be locally controlled can’t report temperature, I would also have to buy some room temperature sensors which are expensive…
Door contacts, for MAX! cost 15euros, the ones for z-wave costs a lot more… They do have more functions , but I don’t really need them.
I do understand that z-wave might be the future, but right now this is cheaper and more convenient :smile: and in the future when z-wave becomes cheaper or when I would need it, I can always but it. I would still save money but not choosing the valves now.

When i first dreamed of having some home automation that was the dream, 24V AC valves and a micro-controller with wifi.
Biggest problem are the wires, I don’t really want to run wires around the house. I don’t have any plugs close to the windows/heaters and this would become a costly project and also not pleasantly looking. and when I move, I have to redo everything.
So because of this I would consider MAX! mostly as with the homegear binding it seems to be what I’m looking for.
I don’t know why the developer of openhab can include in the MAX! CUL binding the implementation homegear is using, but I hope in the future I could use only openhab without having to work with homegear. :smile:

Next week I will order a cube (until I finish implementing the bindings) , one valve, a window switch and a CUL stick and start my work :smile:

I’ll try to come back here with updates and problems :smile:
Thank you all for the help :smile:

Thank you very much for this guide.
It helps a lot in pulling people over a certain threshold.

For me it would be strange to have this small device’s placed near a window,
and what about the power supply?

Ok. So in the mean time I figured out that due to time limitation and financial constraints I will postpone this for one year. I managed to learn a lot of stuff and I hope that in one year I will do it. OpenHab seems like the logical solution for my central “hub” due to the remote connectivity which doesn’t require any port forwarding :slight_smile: and homegear seems to be able to handle the cube pretty nice.
Thank you all for the answer. As I am still getting updates and as I managed to research a few things previously. I can answer to Forssux.
You would preferably find a way to make it discreet. you can just run the wires from the magnetic reed to the micro-controller. So you will have the reed on the windows and two discreet wires going to a small hidden away box. it doesn’t need to be all next to the windows. You can have 1-2 meters of wire between the reed and the MCU without problems :slight_smile: . The power supply has to be next to the MCU.

HI there,

A little late to this discussion. I have a MAX! cube and a couple of TRV’s. Note, I’m in the UK where the norm is to have a boiler in the house, whereas MAX! was primarily conceived with the idea of centrally provided heating - therefore a big limitation is the absence of any off the shelf boiler-interlock.

That said, the systems works, but it’s clunky, the UI is basic and the Cube (or could be the plugin/binding for Openhab) isn’t the most reliable.

So, limitations:

  • No boiler interlock - individual zones/radiator can’t demand heat unless the heating is on
  • Cube interfaces aren’t robust - it stops responding after a while and needs reseting
  • the TRV’s don’t report temperature/valve position unless the valve moves - not too much of a problem, if it weren’t for the flakey-ness of the cube!

I haven’t purchased anymore TRV’s above the original two I bought with a cube, they’re great as timer controlled TRV’s and could easily be integrated with a presence detection to reduce demand temp’s in the rooms when you’re out.

I’m keeping an eye on the Open TRV project which will provide more of what I’m looking for which is to minimise heating of rooms I’m not using.

The one advantage to the MAX! TRV’s over standalone digital timer controled TRV’s is the ease of programming - the standalone versions are tedious and complicated.


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It seems that everybody is writing their final conclusions, so will I.

  • These systems, will not! save you money. Its not meant for that. Its for your comfort (which has another price). And maybe its for your fun, its a toy. Especially if you do not have boiler in house. And even then, its more or less a toy for a boy who have grown up :slightly_smiling:

  • After thinking more clearly, I understood, that OpenHab is not a toy that works from scratch. So I can’t experiment with wires and Dallas temperature sensors. It will take time, which I will not have.

  • For 3 units of radiators I chose 3 230V (5 Eur each) valves and 1 Danfoss FH-CWF (29 Eur). This is cheaper and it just works. I do not need to control it over phone, because its not mandatory. And I will have two setpoints thats sufficient for any one of you :slightly_smiling:

  • in separate rooms with one radiator I will not use any "smart"things at the moment. I will use regular valves, which reacts to temperature. If I will want to play, I will buy dirt cheap Danfoss living eco (34 Eur). But remember if you will have kids in that room, simple temperature valves will be enough, because children will need temperature.

Nice topic.
Keep it up!


Hi James,

Thank you for your feedback. I’ve looked at the openTRV but for me, it is only smoke and mirrors. They keep using OPEN in the name and the open hardware logo and brag about their versions but I yet have to find anything except a brief badly written manual for the TRV and 1 or 2 pictures. So I don’t really believe them.
For the cube. I don’t know how to boiler is, we have central heating in Denmark and we share a so called boiler (heat exchanger) with the entire building.
MAX! has actually a relay plug. So if the boiler can be turned off by unplugging it and on by plugging it back on, that might be a very simple solution. The plug is dirty cheap.
otherwhise, you could just open the plug, remove the relay for the socket and use the relay to control the boiler. I assume your boiler has two wires which when connected turns on the boiler and when disconnected turn it off.
So if you remove the relay from the 230V plug, you can use it to connect and disconnect the wires :wink:
I know the cube has limitations, but if you have a look at the homegear binding, they’ve actually managed to use the cul stick to control the MAX! peripherals without the cube. That proved to be much more efficient.
The limitation of the TRV reporting temperature is well known, that’s why it is recommended to use a wall thermostat with them. For me, that’s not a big deal. for as long as I can tell them what the temperature should be, I don’t care, as they will adjust the temperature by themselves. I was planning to try and force them to report the temperature by asking the to change the temperature (something like: if it is set to 20C. Ask them to go to 30C, then ask them to go to 5C and them ask them again to go to 20C). So even if they are fully opened or fully closed they will be forced to report back. :wink: Again, this is just an assumption, but I don’t see why it wouldn’t work. A bit overdue, but it’s ok. I think the limitation is in order to keep the lifetime of the battery as good as possible, but also due to the duty cycle limitation of the communication protocol, which was around 10%

This systems will save you money. And I can guarantee that. For me the savings were around 30%, no joke. I pay my heating with my rent to the company who owns the building. Every month, I give them a little bit and once per year they recalculate. I installed them in my second year of living here, and managed to save around 30% (got a lot of money back form them).
So at least for me they save money. i prefer to have in the house around 21-22C. there was a study in Denmark, that showed that each 1C above 20C is at least 10% extra on your heating bill.
I normally keep the room around 18C while I’m out of the house during the day, and 20-21C when I get back. the heating in the bedroom is on only from 23:00 to 7:30 each day, in the rest of the time it’s on 17.5C (the bedroom can heat up faster).
I don’t want to lower the temperature even more as I will use too much heat to heat it back up, and also because all the objects (couch, bed, chairs) will be too cold.
I’ve considered using valves, but the 230V ones I’m a bit concerned to use, as I’m not sure what how well they are designed internally, and I don’t want 230V on my heater :))
Also, you need a really good controller for them if you want to keep the temperature steady, as the radiator and flow of water are very non-linear :slightly_smiling:

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