Now far be it from me to accuse the wife of ever leaving things on when they don’t need to be but …
She does.
The lights and ‘certain’ power sockets have been dealt with.
The latest in my list is the cooker hood.
So I was thinking about putting a switch or better a double switch into the hood.
I can power it from the standard feed and use the switch output from the light as an input to switch the light.
So far, so good.
The extract fan is a bit of a puzzle.
As I need the output of this to go direct to the fan, but also to be the input for the smart switch. My thoughts go to using a relay switch so the control is not bypassed. I may need a separate relay though as the live may conflict with the live from the (smart switch) feed ???
Has anyone tried this?
Does the momentary disconnect between fan speeds cause any issues ?
I assume the reduced speed uses triac chopping on the output, not sure if that will cause multiple triggers but as the input expects ac anyway … ?
Any thoughts or opinions welcome.
If I don’t hear anything, I’ll invest and experiment then report back.
Edit: some subsequent thoughts : -
If I use the smart switch (SS) to turn off the fan (after (say) 4 hrs) then the SS output will be off with the fan switch (DS - Dumb Switch) still on.
So when she/I come back to use the fan, we press any of the fan buttons, then probably nothing will happen until we switch the fan (DS) off, which will turn the SS on, but the DS will not have an output.
So I’ll have to create an input boolean to note if the timer turned the fan off.
If so, switching the SS will turn the bit off and then turn the SS off aswell. Meaning; we’ll have to turn the fan off (DS) then on again (DS), (may help train her to turn it off in the first place).
So I think I’m leaning towards a double switch (cheapest solution, either triac or relay (shouldn’t matter)) with a relay (mains voltage) to enable the fan output.
Edit2: What I really need is one of those boxes with a button on it, you press the button ‘on’ and the box opens, a finger comes out a presses the button ‘off’.
I’ve been pondering the best way to do this for a while. One option I’ve thought about is using a switch to turn it off - and then use a motion sensor to turn it back on when someone is in proximity… that way it would always work when you wanted too. This is a bit clunky for me, but it’s the best I’ve come up with without replacing the physical switch on the hood
I’m not sure that my setting timers to turn lights off after a set duration, either makes people angry when they spend more than 30 mins on the toilet - Or lazy because they know the light will switch itself off.
This is pretty much the same, so I’d be happy to cause a little disruption just as a reminder (the first turn on after a timer off will just switch it off to get it back in sync) - don’t tell the missus that though
Having recently stripped an overhead extractor I found that the speed is controlled at the motor level with 3 different inputs. I think this is a common way of control as I have come across it with other inline fans. So I imagine a 3 or 4 relay like the son off one would work for the 3 speeds and the light. I imagine you could use the current switches as low voltage triggers for the relays?
Okay, I see what you mean.
Further thinking on this yields the following : -
Use a double relay Smart switch
Light controlled as previous (light wire becomes input for switch 1)
feed fan outputs (all of them via 3 separate diodes to give 1/2 wave rectified input to the switch 2)
Also feed the 3 wires (without diodes) into 3 poles of a single relay that then passes them on to the motor.
What haven’t I condidered ?
I’ll order up a switch and give it a try
Sorry, must not have explained properly.
The cooker hood outputs to 1 of the three
I just put a relay contact in each feed - 3 contacts in 3 wires
So it would operate as normal with the 3 contacts all closed, but would not operate with the contacts open
I would also feed one of each input through a diode to feed half wave rectified ac as an input.
There’s no cross connection as the diodes (if you assume just two) form a blocking set like a bridge rectifer. The same works with 3.
From your diagram I would think that the hood switch simply allows ‘live’ to ‘one’ of the three inputs and let’s the windings do their thing.
As I said, I’ll give it a try when the bits arrive and report back
Thanks for the input
If you look at @Drdave 's drawing you get the general idea, some motor arrangements may vary slightly,
i.e. some motors have separate windings for the different speeds.
The point is if you look at the sketches below (the first of the original and the second of the modified) this should just about cover all situations.
In my case (with the hood I actually bought as a replacement) “The Fan Switch” was actually an ‘electronic’ switch (so I couldn’t use it on the new hood - but it was built into and worked on the old one, subsequently I stripped the useful parts before scraping the old one)
Thanks, my hood as you can see is purely mechanical no microchips to control, so I went ahead and ordered Sonoff iFan3, I think that will work, I will test and come back to let you all know.
Ha ha ha !
Very droll.
I was considering the casual browser who might (with a touch more information) try something along these lines - AND I like to have all relevant information togetherl
Thanks for the link though
Edit: had a read, and it’s not clear how it works
Is it thyristor control (don’t see any other option for the wiring detail)
How would that help for the two types of fan previously discussed
Running a full speed winding (say) on low power could cause overheating (why you set min speeds on some motor sets). Or has that already been taken into account ?
Don’t see how you control this locally (the wife would not be happy having to juggle a remote (or a phone) mid bake)
The standard hood controls would then just be a lure to make people look foolish ?
My plan is to replace the current control panel (4 way slider for fan) with a 3D printed one with only 2 momentary buttons, one for light, one for fan.
Using a 4 way ESP relay board and ESPHOME, use 1 relay for the light and the other 3 for the 3 speeds. Using a software interlock and automation in ESPHOME to inch through each speed, ie turning each motor winding on in sequence, then all off. I think Sonoff iFan can do this inching as well.
I’ve tested this with a Shelly 2.5 using only 2 relays on Low and High and works well:
Reason I want to do this is sometimes it’s not used so going to use some kind of automation when heat is above certain level at the hob/extractor turn on the extractor and turn off when its cooled down.
I’ve looked at measuring current with a power plug on the igniter but its not enough change for long enough for it to be recognised.
I really wasn’t trying to be droll. Just asking what other info you might need.
I’ve got two of them running now so I figured I could at least try to answer questions.
It’s fully relay control logic controlled by the outputs of the ESP chip which puts varying capacitance inline with the fan motor windings (I believe from what I remember they are 3 and 5 microfarad caps) so it varies the voltage delivered to the motor in that way.
Local control and HA integration is provided by flashing with Tasmota.
As far as I know there is no allowance to bring in speed control inputs to the controller so, yeah, the existing controls would be purely cosmetic.
So HA dashboard, voice or using the 433mhz remote would be the only way I could see it working.
That wouldnt change voltage but the phase angle change would be sufficient to reduce absorbed power - thank you (you don’t need to explain it in terms any idiot can understand - I’m a very specific type of idiot )
So far, I’m liking @Holdestmade 's solution as it does the same as mine but dispenses with some of the major rewiring and the fudge with the diodes to provide switch inputs (which may not work with ALL smart switches)
I think a combination of temperature and humidity would cover all bets and make it truly smart.
But the hood fan makes a noise (on the higher settings) so ‘the wife’ mostly turns the fan off.
The light though - I think she’d leave that on 24/7
My general concern about all of these is that (though the one I tested works) the hoods are basically a Faraday cage with openings on the back and an aperture where the air grill is. Not sure if ‘some’ users would have issues with the wireless connection - any ideas ?
Never thought of that, but I have no issues with wifi bulbs in completely metal light fittings.
There are D1 minis with external antenna so maybe could use that, maybe hide it towards the back. You’d need a 4 way relay board connected to the D1 mini though, rather than the all-in-one esp01 boards.
Brown wire is live, blue wire is neutral, on the “push button”, first L with yellow wire goes to the LED driver for the two lights under the hood. Second L is live wire from mains. 2 is speed Low, 3 speed Medium, 4 speed High.
iFan has these wires: L (live input from mains) N (neutral input from mains) and three output wires: COM (neutral output), FAN (live output to fan, which varies values to change speed), LIGHT (live output for lights).
I know how to wire the lights. My idea is to use the black wire (fan speed HIGH winding) on the FAN output of the iFAN 3 and then it will vary the speed through voltage difference? My understanding is that’s how it works? I know the capacitors on the iFan will have something to do with it…
The motor has 7 wires, two (yellow and brown from the motor) come from a large cylindrical capacitor that I assume should remain in place, in addition to the capacitors from the iFan? Then wires white, black, red go to different windings to control speed. The live from the mains seems to be bridged to each speed within the push button control. From my observation it seems like the medium speed is achieved by bridging two windings (medium and low). Highest speed is its own winding, which is why I was planning to use this on the FAN output of iFan and the neutral goes to COM and with the neutral for the LED driver for the hood lights.
The motors are either one or the other:
Can anyone with experience in motors comment on whether there is any problem with this plan?
Edit:
I did like I said above and it works, but only on the top speed. Any other speed and the extractor can be heard to struggle and I’m sure that’s not healthy for the motor at all. I would like to retain all speeds if possible and was wondering if anybody had any ideas!? I thought about using a relay board but how to trigger using just one wire from the output of the iFan?!
From what I know ifan does not seem like the right fit for this project. I would use esphome with a relay and node mcu. It’s a little more complicated but it will be an exact fit for this setup.
Disconnect all the front switches on the hood. Wire the brown to the common of all the relays. Then yellow white red and black to the n/o contact of the relays. The switches on the hood wire to separate gpio pins on the nodemcu.
This way your just taking control of the switches all the other wiring is in place. The brown and yellow on the motor is likely a high temp fan switch. The grey who knows there maybe other models that have variable speed. That might be compatible with the i3 fan controller, please don’t wire to it, 'to try it out". Only do so if you know exactly what it is for.
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