Kitchen extractor automation

Hi All,

Just though i would share another approach to "automation".
In the never ending fight against moisture when I installed our cooker extractor hood I wired it up to a microwave motion sensor so anytime you went near the cooker the extractor switched on.
(Automation was necessary to avoid the "sorry I forgot" attitude of some!)

However, the motion sensor approach had the downside that it would often mean the fan was running when there was no cooking happening and the fan was (to quote SWMBO) "loud enough for the whole village to hear" .

I was recently suggested to use a current sensor on the main cooker feed which I have just done and though I would share.



There is an adjustable current transducer which the main cooker (and a secondary socket feed) run through, when the cooker is switch on and draws current this closes the transducer output relay and then closes a timer latched relay which in turn switches the main extractor on. It is very sensitive as even the cooker LCD clock drew enough to trigger the transducer (until I adjusted it).

Very happy with the end result (and the wife is happy to).

Cheers,
Richard B.

p.s. Yes, the top gland was tightened :roll:

And I thought I had too much time on my hands.

As my First Lady would say - the devil makes work for such!

She is also an ardent evangelist of the GOYA movement - it therefore pays not to stand still too long around her.

I have widget that does a very similar thing in my workshop by automatically switching on the dust extraction when I use my bandsaw. It also has a short overrun time so that the extraction doesn't stop immediately the bandsaw is switched off.

Microchips are amazingly cheap and easy to use these days and I recently cobbled together a DHT22 temp/humidity sensor and a Pi zero with wifi and bluetooth, all for less than £20. I'm not using it to switch anything on or off (a simple addition with a suitable relay) but I can now check temperature and humidity on my PC/tablet/Smartphone via a simple webpage.

Why? Because I can I suppose. A bit like climbing mountains because they are there, except it doesn't take as much effort of course.

Still, it's a handy thing to leave in the cellar so not a total waste of time.

Flyfisher said:

Microchips are amazingly cheap and easy to use these days and I recently cobbled together a DHT22 temp/humidity sensor and a Pi zero with wifi and bluetooth, all for less than £20.

Click to expand...

I have a number of temperature/humidity sensors dotted around the house all linked to a central computer using modbus - Wouldn't take much to write a script to turn on the kitchen extractor by way of a Sonoff smart switch.
If you are looking for really cheap WIFI ready microcontrollers, the ESP32 based boards are worth looking at - They pop up in a lot of smart switches and a whole host of IoT devices. Many of the boards are eminently hackable and can be flashed with alternative firmware (I'm running a few light switches flashed with Tasmota).

Flyfisher and PaulC, wow :shock:

I feel like I have taken a very low tech approach :lol:

I do enjoy using (sympathetically) high tech in an old house.

Flyfisher said:

I have widget that does a very similar thing in my workshop by automatically switching on the dust extraction when I use my bandsaw. It also has a short overrun time so that the extraction doesn't stop immediately the bandsaw is switched off.

Microchips are amazingly cheap and easy to use these days and I recently cobbled together a DHT22 temp/humidity sensor and a Pi zero with wifi and bluetooth, all for less than £20. I'm not using it to switch anything on or off (a simple addition with a suitable relay) but I can now check temperature and humidity on my PC/tablet/Smartphone via a simple webpage.

Why? Because I can I suppose. A bit like climbing mountains because they are there, except it doesn't take as much effort of course.

Still, it's a handy thing to leave in the cellar so not a total waste of time.

Click to expand...

Oooooh this! I have lots of individual monitors dotted around but no way of monitoring trends centrally - if you wouldn't mind sharing what yoo dun I'd be really keen to do something similar.

a twig said:

Oooooh this! I have lots of individual monitors dotted around but no way of monitoring trends centrally - if you wouldn't mind sharing what yoo dun I'd be really keen to do something similar.

Click to expand...

When I first started down the road of home automation, I initially wanted a simple way to control my heating system that was a little more advanced than a thermostat & timer. The starting point was this system - https://www.instructables.com/Raspberry-Pi-Home-Heating-Controller/ - Basic, but easily adaptable and ran on an original Raspberry Pi. It didn't take long for a search for a system that could be expanded to do even more. Primarily, log data from various temperature sensors and monitor power consumption. After trying several of the open source offerings out there, I settled on Home Assistant. It didn't take long to find that a Ref.1 Pi was way too under powered, so swapped it out for a FriendlyArm NanoPi with a custom heat sink.
Having started down the rabbit hole of "tech", the amount of data I was logging was killing SD cards in a matter of months. A more conventional computer was added to the mix to act as a data store... With more computing power on hand, more software was added (FluxDB and Grafana) to generate fancy graphs from all that data. Grafana has the ability to run in a web browser so you can use just about any device to view the graphs. Home Assistant also has a web interface, and if you have smart switches or relays attached, these can be turned on/off with a simple click - Saves having to get up to turn the kitchen lights off

If you are planning on recording much data, I would strongly recommend using a computer with a conventional hard drive - SD cards and SSD drives will die pretty quick.

Cool, I considered doing the same thing myself for the kitchen hob. My central extractor does have a humidistat but its a bit hit or miss. It doesn't always kick in if you are creating a lot of steam in the kitchen.

I have flow switches on the shower and bath pipe work driving a bank of relays. One is an overrun timer to put the fan into boost. Others turn on the mood lights and mirror demister. I'm going to add one more to bring on the bathroom heating zone for an hour or so to help dry up the room. I really like the Finder DIN rail mounting relay modules. Have dozens of them all over the place. Low tech enough that a future owner might just be able to maintain them.

I have X10 switches and dimmers on many of my lights and a linux box that schedules them according to lighting up time. My next door neighbour once remarked that my lights always come on at the same time... Really, winter and summer?

More importantly it turns everything off at 1am as certain family members seem to think that light switches are 'one-way'. X10 is getting a bit out of date now but I have a good stock pile of modules and all the different light fittings are wired back to a central box so if I have to change the implementation I can.

My other bit of sympathetic automation was alarming the windows by recessing the detector into the bottom of the stile with the magnet on the inside edge of the sash. Completely invisible and accessible through the weight door in case of problems. I hate surface run wiring of any sort. Still have a maze of internal telephone extension wiring to strip out.

fernicarry said:

certain family members seem to think that light switches are 'one-way'

Click to expand...

:lol: spot on with that one !

I have started using bulbs with built in PIR sensors in some areas for this very reason.

Cheers,
Richard B.

a twig said:

Flyfisher said:

I have widget that does a very similar thing in my workshop by automatically switching on the dust extraction when I use my bandsaw. It also has a short overrun time so that the extraction doesn't stop immediately the bandsaw is switched off.

Microchips are amazingly cheap and easy to use these days and I recently cobbled together a DHT22 temp/humidity sensor and a Pi zero with wifi and bluetooth, all for less than £20. I'm not using it to switch anything on or off (a simple addition with a suitable relay) but I can now check temperature and humidity on my PC/tablet/Smartphone via a simple webpage.

Why? Because I can I suppose. A bit like climbing mountains because they are there, except it doesn't take as much effort of course.

Still, it's a handy thing to leave in the cellar so not a total waste of time.

Click to expand...

Oooooh this! I have lots of individual monitors dotted around but no way of monitoring trends centrally - if you wouldn't mind sharing what yoo dun I'd be really keen to do something similar.

Click to expand...

Because my restoration has been fairly 'full-on' in most rooms, it has been easy to install lots of network cabling so that I now have RJ45 outlets in most rooms all feeding back to a central 'hub' cabinet in the 'plant room'. With the cabling infrastructure in place it's very easy to plug a suitable sensor into an RJ45 outlet and then patch it into an Arduino or RPi located in the hub cabinet.

In this way I have 10 temperature sensors patched into a single Arduino board with a small LCD to sequentially display the temperature in each room. The Arduino also generates an updating web page easily accessible from any PC/tablet/smartphone in the house.

Here's the current display (with a couple of anomalies you might spot):

OUTDOORS 61.4oF 16.3oC
PLANT ROOM 77.2oF 25.1oC
KITCHEN 69.9oF 21.1oC
SITTING ROOM 72.4oF 22.4oC
DRAWING ROOM 63.3oF 17.4oC
MAIN BEDROOM 65.9oF 18.8oC
WHITE ROOM 77.3oF 25.2oC
ATTIC ROOM 65.1oF 18.4oC
AQUARIUM 78.8oF 26.0oC
COMMS CABINET 80.3oF 26.8oC

(which lines up on the webpage but not when cut-n-pasted!)

I've not bothered to investigate exporting the readings into something like Excel for charting trends, though I'm sure it could be done.

Oh dear, I really am a Luddite. IT director at work tried to get me interested in Arduino and failed.

A programmer friend of mine has cobbled together an chicken-shed-door-opener out of an old cordless drill and I think an early Raspberry Pi, so he can let the chickens out whilst still in bed on a Sunday morning using his phone. I did say can he not just use a timer, but apparently that’s too simple!

Flyfisher said:

I've not bothered to investigate exporting the readings into something like Excel for charting trends, though I'm sure it could be done.

Click to expand...

A sample of temperatures from the last 24 hours..

Having dipped into this thread several times now my initial reaction has been to marvel that even 'tech-geeks' have an appreciation for period homes of character. Whilst having no particular grievance with such, I did after all work in the IT industry for most of my professional life, I have marvelled at the extent to which many have now become wedded/dependent on ITC technologies in their homes.

Call me a luddite if you wish but I have - for many years now - done my very best to leave the technology in the office and out of my house and cling even now to the KISS mantra. Its why, after all, I/we bought this pile of sticks in the sticks. :roll:

I started out with a simple desire to have a bit more control over the heating system without spending a fortune on a Nest or Hive system (and a refusal to pay an annual "fee"). Then I started to add sensors dotted around the house to collect data - As I make changes (swapping radiators, adding insulation, etc), I should be able to make an informed judgement as to which improvements have been worthwhile.
The extras like smart switches, well, they are just there "because I can"

Cubist said:

Having dipped into this thread several times now my initial reaction has been to marvel that even 'tech-geeks' have an appreciation for period homes of character. Whilst having no particular grievance with such, I did after all work in the IT industry for most of my professional life, I have marvelled at the extent to which many have now become wedded/dependent on ITC technologies in their homes.

Call me a luddite if you wish but I have - for many years now - done my very best to leave the technology in the office and out of my house and cling even now to the KISS mantra. Its why, after all, I/we bought this pile of sticks in the sticks. :roll:

Click to expand...

I don't think there's any disconnect between 'tech geeks' having an appreciation of period homes. After all, we're all 'tech geeks' to an extent, which is why and how we're posting on here in the first place. If we're being strictly 'period' then there's no place for electricity or modern appliances in many of our period homes, nevermind the IT required to access the internet, so it's really just a matter of degree.

People might like living in period homes but I don't believe anyone would like, or tolerate, genuinely authentic period living . . . unless they were minor royalty perhaps. So in most cases 'period living' in the 21st century is just an illusion, or should that be delusion?

Flyfisher said:

People might like living in period homes but I don't believe anyone would like, or tolerate, genuinely authentic period living . . . unless they were minor royalty perhaps.

Click to expand...

Don't know about previous generations, but the Victorians were very keen on adopting the latest gadgets. William Armstrong's pad at Cragside (built between 1869*1895) is claimed to be the first "smart home" in the world - https://www.nationaltrust.org.uk/cragside

Exactly. Without this there would be no progress at all.

Sure, we can all bemoan certain aspects of 'progress' but my guess is that such moaning been a constant throughout human history. However I'm in little doubt that, in the round, today's standard of living for the vast majority of people is hugely better than anything in the past.

First world problems, perhaps?

.

RBailey said:

Hi All,

Just though i would share another approach to "automation".
In the never ending fight against moisture when I installed our cooker extractor hood I wired it up to a microwave motion sensor so anytime you went near the cooker the extractor switched on.
(Automation was necessary to avoid the "sorry I forgot" attitude of some!)

However, the motion sensor approach had the downside that it would often mean the fan was running when there was no cooking happening and the fan was (to quote SWMBO) "loud enough for the whole village to hear" .

I was recently suggested to use a current sensor on the main cooker feed which I have just done and though I would share.



There is an adjustable current transducer which the main cooker (and a secondary socket feed) run through, when the cooker is switch on and draws current this closes the transducer output relay and then closes a timer latched relay which in turn switches the main extractor on. It is very sensitive as even the cooker LCD clock drew enough to trigger the transducer (until I adjusted it).

Very happy with the end result (and the wife is happy to).

Cheers,
Richard B.

p.s. Yes, the top gland was tightened :roll:

Click to expand...

Sooooo - a couple of years on, all is still good I take it?

Can you share details please of what adjustable current transducer and timer latched relay you used? I have 2 digital showers to connect, current consumption will be very low but if your cooker clock can be picked up it should be OK. I was thinking I could use your idea to switch the extractor fans on whenever the shower is started - and in the room with a bath in it as well, add a flow switch to the bath feed.

This should stop my darling offspring (& Mrs F!) from either forgetting to switch the fan on, or only switching it on after their bath or shower, once all the condensation has already formed :roll: . I did try a fan with a humidistat a while ago, it was worse than useless.

Feltwell said:

Sooooo - a couple of years on, all is still good I take it?

Click to expand...

Yes, very happy. The timer is on a 5 minute overrun which is as much as management will tolerate but I sometime think 10 would be better.

Feltwell said:

Can you share details please of what adjustable current transducer and timer latched relay you used? I have 2 digital showers to connect, current consumption will be very low but if your cooker clock can be picked up it should be OK. I was thinking I could use your idea to switch the extractor fans on whenever the shower is started - and in the room with a bath in it as well, add a flow switch to the bath feed.

Click to expand...

In the end I used this current sensor:
https://www.amazon.co.uk/gp/product/B082KHV41C/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
it is o.5 to 50 A input. As the sensor is self powered I was worried about the full cooker draw smoking the sensor.

I also bought one of these:
https://www.amazon.co.uk/gp/product/B08P1DTQSL/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
but as its only 0.2 - 30 A i didn't use it.

I have the wire only once through the transducer but apparently twice will increase the sensitivity (twice the input coil "windings").

This is the timer relay I used.
https://www.amazon.co.uk/gp/product/B07PYQY2CG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I also got a bunch of DIN rail bits, because I wanted to as I'd never played with it before.
(Some okay selection kits on Amazon as well.)

Cheers,
Richard B.