How to Design a Home Energy Saving System Using WiFi Keyring Presence Detection?

Hello,

I'm working on a project to design a system that basically turns off all
non essential electrical appliances in the home when it is not
occupied. The idea is to reduce energy waste caused by lights, TV's
computers etc being left on accidentally.

So far i'm thinking that each occupant within the house could carry a
small keyring sized device, and basically whenever the keyring leaves
the building the system will automatically turn off all non essential
devices and appliances. My background is more mechanical engineering
than electrical so i'm struggling to figure out technically how this
would be achieved.

Would it be possible to have the "keyring" connect to a wifi network
within the home, then whenever the connection is lost, it could be
assumed that the occupant has left? Then have something wired up to the
fuse box to actually turn off selected switches?

The solution doesn't need to be perfect, just functional.

Any input is greatly appreciated,

thanks.

A few thoughts on this.

First, I would be inclined to use home automation switches that you plug into outlets to turn off the power to individual devices rather than  wiring to the fuse box. First off, it's likely to be safer and secondly, fuse boxes are not always wired in a logical fashion to allow you to turn off "non-essential" appliances without turning off something essential (like the device that senses that you've returned home).

As to the "keyring" idea, I would be inclined to use Bluetooth BLE rather than WiFi to conserve power. Of course this means you might need multiple receivers in a house which would all have to be powered on continually. Maybe even better to use something like LoRa which has a longer range. Or perhaps you just use the person's smart phone.

And then there are the appliances that you might occasionally WANT to have powered on while you are gone (for instance starting the dishwasher just before going out to run errands). If you use individual home automation switches, this can be accommodated by programming.

George... I have seen intercoms that work over the mains wiring and there is no reason you could not do the same here.  Transmit a code from your controller on a carrier frequency (usually about 200 KHz is used) over the mains wiring, and the individual switches will pick it up and act accordingly.  You could use the well-known HT12E and HT12D ICs to switch up to 4 groups of devices using a fairly secure code, or use other arrangements to switch more groups if you need.  Any number of devices can pick up a code, so you could use one group for temporary home leave (PCs, TVs etc) and another for longer absences (dishwasher, heaters etc)I must point out that to do this, some mains wiring is involved and this is very dangerous if you don't know what you are doing. In some countries it's actually illegal if you are not qualified.
You may have seen in some hotels a device where you insert your key card in a holder and this enables the air conditioning and lighting.  You could use a similar arrangement.Finally you can get such devices ready made like thishttps://reductionrevolution.com.au/products/efergy-remote-controlled-power-sockets?utm_medium=cpc&utm_source=googlepla&variant=5220062461984&gclid=EAIaIQobChMI6OuchK7E2QIViAcqCh0DmQkpEAQYASABEgLAjfD_BwE
I have a similar thing and it is possible to get more than one remote working on a channel.Cheers // David

Hi George-  Here are some pieces that may be of help.   If all of the occupants of the house carry cell phones, look into "geofencing" apps.  These allow you to take actions depending on whether or not a phone is located within a specific geographic area.  To tie this into a home automation system, take a look at If This Then That .Now for the home automation part. My favorite is Insteon because it use a dual-mesh technology for reliable communications. You might take a look at the Universal Devices  ISY994ZW, which ties everything together. In addition to Insteon, the ISY994 can talk to Z-wave and infrared devices. The ISY can run easy-to-understand scripts, so if the house is not occupied it can adjust the temperature, make sure the doors are locked, make sure the oven is not on, etc., etc.BTW- The ISY also supports infrared occupancy sensors, but you'd have to put one in each room.
Hope this helps.
-Rick

@davi_d "... You may have seen in some hotels a device where you insert your key card
in a holder and this enables the air conditioning and lighting.  You
could use a similar arrangement. ..."The hotel that I stayed at while I attended ESC in San Jose last December appeared to have an arrangement where the air conditioning only worked while you are in the room. It may have been tied in to the key card but there was no way for me to easily test it.

George,Here is a  review of remote control outlets similar to what David mentioned
https://www.safewise.com/blog/5-best-remote-control-electrical-outlets/

Thanks Elizabeth.  The hotel you described might have had a movement detector and a timer (maybe half an hour) but you'd probably see that go off eventually, eg when watching TV and not moving.George - the remote control mains outlets that I mentioned (and No 5 in Elizabeth's link) are easy to adapt - you just take them apart and put a relay contact across the switch you want to operate.  An Australian magazine Diyode has a project on this in this month's issue.