If Dimmer A ON > 5 minutes Turn on Dimmer B for 2 hours

My wife has asked for this so my reputation is at stake :slight_smile:
As usual I would prefer to solve this without involving runtime PC or Pi software if possible.

A is bathroom downlights on VMBDMI-R.
B is a towel rail, also on another VMBDMI-R

A is switched on from PB1 in a VMB8PBU (only two buttons used, other six are unconnected).
PB1 also toggles a virtual relay that has a 504 to switch the extractor fan for that bathroom (on whilst light is on, but also runs on for 10 minutes more after light goes off). That works great.

The thinking is, if you take a shower later in the day something will spot the bathroom light being left on for > 5 minutes and then will automatically switch on the towel rail in that bathroom for 2 hours to help dry the towels after. So clearly there is going to have to be a 5min timer and a 2hr timer somewhere.

I need to do this for four bathrooms and I only have three virtual relays spare so they are a bit precious. I do have lots of VMB8PBU, each with spare unconnected inputs. Is this doable? Preferably using enable/disable program and button-press timers rather than virtual relay timers?

The towel rails in bathrooms all over the house already switch on at 6am every day for 2 hours. That was done using a single VMB8PBU spare pushbutton channel setup with a program to press the button for 2 hours at 6am every day. Then several 104 (Follow/Momentary) from the pushbutton to the towel rail dimmers.

I think the first question has to be…

Why have you got a towel rail on a dimmer?

All the towel rails are on dimmers so they can be set to lower power.
You don’t need much heat to dry just slightly damp towels.

At our last house (wired before we went velbus), we replaced the fused spur outlets at towel rails with neat little towel-rail controllers that were a drop-in replacement. Those let you set a power level. It was neat to be able to control how hot the towel rail gets… lower heat => energy saving and no scorchy smelling towels :slight_smile:

This time around I figured we could do the same using velbus… so no fiddly controls.

It seems to work well.
And four bathrooms = 800W so if I can cut that to 400W and still keep towels warm enough then great.
These towel rails not as hot as the ones we had before though so not strictly as necessary.

Fair enough.

Interesting application.

I’ve got an extract fan running on a Velbus dimmer for one client, to create something similar.

Have you looked “delayed on” action?

With the initiator as the lighting Dimmer Channel and the Towel rail as the subject?

See how you get on with that, then we can look at fine tuning it, within the Velbus ecosystem.

I am trying to understand what you want to do… maybe I’m wrong but it seems every time you want the towel rail to work, you want it to run for two hours. Right?

If my assumption is right, then everything could be done by programming a two hour on timer every time you push the button. You could manually push it (short push) or have the program push it… I did not check if the settable timer on is available for the dimmer, I assume it is. I use it for the outside dimmed terrace lights.

So you could remember to push the button every time you need the towel heater, that would avoid running it every time the lights have been on and it was not for taking the shower during the day. What is the probability - with all these bathrooms - that a second shower would be taken by the next morning where the 6 am cycle would turn the heating on? I realize that is not what you asked.

I believe you asked that if the lights were turned on for a full five minutes that tells you they were on for taking a shower and the clean person did not forget to turn the lights off. So you want that to turn on the towel heater, right?

The question would then have to be: what turns on the lights? If it is only a push button, a delayed on timer in the dimmer for the rail will keep running even if the lights are turned off before the 5 minute light timer runs out. I have not thought or tested this out completely, this is the direction I was taking: the light is only switched on and off using the pushbuttons. Turning lights off could push the towel heater button. Turning the lights on sets a 5 minute during blocking of the towel button. If the lights are turned off before the 5 minutes, turning on the rail is blocked.

Yes.That’s right.

Yes, that’s what I currently do (program pushed, using an unused 8PBU input) at 6am every day. That works well.
But if I also have the light-switch do the same then the towel rail will come on for 2 hours every time the lights are switched on. I had thought that might be a bit unnecessary/wasteful but maybe it’s not so bad.
I was hoping to keep the program-pushed 2hr on at 6am but after that to only switch the towel rail on if the light is switched on for eg. more than 5 minutes… ie. if someone takes a shower.

Yes, the lights are only switched on and off using an 8PBU push-button to toggle (0103) or perhaps to Dim/memory at long/short press (0203). I cannot see any way to do different actions at ON and OFF using this approach.


That’s a relay command I think.
Perhaps I should move a towel rail to a relay so I can try that out.

My light switches are all momentary pushbuttons so I tend to use a lot of “toggle” (0103) or “Dim at long, memory or off at short” (0203)

If I have a delayed on for 5 minutes, how do I cancel that if button pressed again (toggling to OFF this time)?

I know, I know, it’s all really crying out for some simple conventional software programming but I don’t want the system to be dependent on a server for normal operation… because not robust enough and needing maintenance. I suppose I might consider an arduino rather than a Pi but that’s getting a bit too custom really.

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EvAndy, I agree, keep it native Velbus is more reliable and lower maintenance. We should do that.

Have you tried the towel rail blocking idea? Did it work?

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I know and understand your reluctance for a logic engine software solution.

I might suggest you pop something like a VMB1RYS
Velbus VMB1RYS: Mini Single Channel Changeover Relay Module (for Standalone and Velbus Operation) – Velleman – Wholesaler and developer of electronics in somewhere just to give you 5 relay channels to use as logic conditioning?

That’s a world of pain.

However, I might consider a simple ESP32 device, hooked up to a VMB8PBU and configured as an 8 in 8 out logic engine.

And very simple Arduino code to apply the logic you want.

I haven’t tried this, but I do have the components on the shelf…

Oh - that is an interesting thought. I’m not an ESP fan unless I need wifi (or maybe you were thinking thon?) but the same could work nicely with a simpler arduino (like an 8-bit AVR Nano).

It would have to fit inside my lighting pattress so it’s a bit tight even for a Nano. The Seeduino Xiao boards are very small though. Will have a think about that.

In other news, I have just stumbled across the dual and multi modes for pushbuttons on a VMB8PBU. I’m now using dual mode long-press to activate unused buttons on some modules and then using those for things like “ALL OFF” or “NIGHTTIME ILLUMINATION WHOLE HOUSE” if pressed for 2 seconds.
I’ve not found a use for “Multi” yet… where short press cycles through sequential presses of other buttons. Feels like that ought to be useful for something but I’m not sure what yet :slight_smile:

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I think I sort of see what you mean… but I’m not sure exactly how to implement that.
Maybe I am just not familiar enough with the blocking and unblocking features… I’ve not used them for anything before.
I don’t want to block the normal operation of the towel rail (on for two hours at 6am every day… set by a program on a spare/unused pushbutton).

  • Andy

Funny you should mention that

I set something up 10 years ago in a room to test and I don’t think I’ve ever really used it

Hey, I found an interesting use for Multi… I can use unused buttons to do “scene” controls with VMB8PBU.

On our last project we used OLED touch panels so mixing normal buttons and scenes was fairly easy to do.

But this time we only have two or four physical buttons per switch faceplate. There is no obvious “ROOM OFF” button although I suppose I could do that with a long press. Most of the buttons just toggle (or dim with memory) individual lamps or collections of lamps (like all the 5A wall sockets in a room). This does not lend itself to scene setups where various lights are at different DIM settings (downlight zones, wall lights, 5A sockets)

I am using VMB8PBU in each switch so I have either 4 or 6 unused button connections. If I put one of the physical buttons into “multi” mode then it can cycle through the unused switch inputs and I can have four or six scenes instead, one of which is all of this room off.

Indeed, that is one of the scenarios that was dreamed up in the early days of Velbus.
I’m really delighted that you’re using it.

I’ll let the man who dreamt that up know, when I see him later today.

Cool! Tell him it seems to work well. I have set-up this up with quite simple combos in several rooms now. I expect we will use it more as we settle in and come up with other ideas for it.

I am also using it to cover for the VMB4DC multi-step dimming bug (putting the dim steps into scene’s with different “atmospheric dim level”).

We had to swap four VMBDMI-R for two VMB4DC+slave-dimmer because some fancy Italian lamps (Tobias Grau designs) that my wife bought did not like the VMBDMI (just 100% on at any dim level).
With the Finder slave dimmers set to trailing edge they work as they are supposed to ie. change colour temperature to become warmer as they dim. I don’t like the colour temp changing personally but at least they do dim now.

I will also soon be using some more VB4DC to generate 0-10V signals to control five extract fans in our ventilation system. They are mainly bathroom and kitchen ventilation but we also run them low to remove radon sometimes.

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I can’t remember off the top of my head how many 4DC units you purchased.

If you need to buy more, it might be worth waiting a little, as the replacement unit that is due to be released soon will be an 8 channel version.

I have two in seperate rail boxes (in the loft) to each other. One driving one slave channel (so 3 spare), the other driving three channels (so 1 spare).

I have a further one in it’s own box next to the ducted fan it controls.
I have a further three ducted fans to do (currently they just have power on/off via vmb4rlyno in the loft) when I get around to it. Unfortunately I can only use one channel at each fan location anyway though. The fans are all above small ceiling hatches for access and there is space and velbus there.

It would be nice to have a decent 8-channel dimmer. If it were still based on 1-10V DC then I think something needs to be done to tidy up the slave dimmers a bit… I find the wiring for several finder 15.11 modules is a bit messy at 5 wired connections per channel (DC-, DC+, L, N, OUT) and the L+N get in the way of the OUT connection.

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I 100% agree

I used to have to deal with stage lighting with 10v control.
Great when there is only 36 channels, but when it got to 100s we were all very happy to learn how to do it the DMX way :laughing:

Who knows what the future might hold for Velbus in the way of lighting control… :wink: