Relay?

[Nicola Paton]

I am trying to build a home automation system using my raspberry pi.

I have it set up to turn on an led bulb via basic web page I have designed. So the next step is to control something bigger. I am looking to control the ceiling light on my sitting room.

I believe I need a relay to control the high voltage circuit. But I am unsure of what relay to use, or even if this is the right component to use.

The Pi can output either 3.3v or 5v.

So my questions are:

Is there a low voltage relay that can work with high voltage circuits?
where would I be able to buy one?


thanks

 

[IzzyS]

Yes. RS Components, CPC, Farnell all sell suitable items, but if you're not qualified to work on "mains" voltage circuits then you run the risk of electrocution/burning down your house.

Good to see that the Pi is sparking interest in "proper" programming though.

 

[telectrix]

solid state relay is probably the way forward. but as said before, best get an electrician to do the 230V bit.

 

[stef]

I am trying to build a home automation system using my raspberry pi.

I have it set up to turn on an led bulb via basic web page I have designed. So the next step is to control something bigger. I am looking to control the ceiling light on my sitting room.

I believe I need a relay to control the high voltage circuit. But I am unsure of what relay to use, or even if this is the right component to use.

The Pi can output either 3.3v or 5v.

So my questions are:

Is there a low voltage relay that can work with high voltage circuits?
where would I be able to buy one?


thanks

Make sure that the PI can drive inductive loads (the relay coil is one) not many
Micro electronic devices can switch inductive loads directly. As mentioned above, I would use SSR.

 

[Darkwood]

Ever since American Pie hit the tv and cinema screens ive seen a growing interest in raspberry pie kits..... loads of disheartened blokes though when they were sent a circuit board! :uhoh2:

 

[telectrix]

is that raspberry pi with custard or cream?

 

[Darkwood]

Warm apple pie!..... but raspberry comes a close secon...... errmmm! So ive heard!!!! :38:

 

[Nicola Paton]

solid state relay is probably the way forward. but as said before, best get an electrician to do the 230V bit.

Would there be one you recommend?

Ive had my pi for a good few months sitting as a media player, loaded with xbmc. Decided its time to have a good play with it.

thanks

 

[grantr37]

Would there be one you recommend?

Ive had my pi for a good few months sitting as a media player, loaded with xbmc. Decided its time to have a good play with it.

thanks

How much money are you willing to spend on components? also how much spare time do you have? there are a lot of people now taking up Electronics (particularly microcontrollers and RISC )as a hobby interest and this invariably leads to an interest in using hazardous voltages in short order to obtain satisfaction from what would appear to be meaningful control projects.....many hobbyists do not relalise how much time can be involved in building even simple projects, or how easy it is to be painfully burned, even to the point of causing fire damage or shock hazards...


your project will involve several small components (up to an order of several dozen) as well as a printed circuit board which will have to be designed and fabricated to handle mains voltage, it will also require a high protection enclosure and correct construction, in the end it may be better to switch a desk lamp, as making use as a break in the supply for a hard wired ceiling light would require you to modify your household wiring and would put your insurance cover at risk along with your personal safety...




I would say that your project could be used to switch many different things that operate below mains voltages and would advise that you stay with low voltages and leave those to experienced Electronics workers and Electricians...


your project will take you about 100 hours in the design and population (construction) parts and you will need to order (send away for) the printed circuit board from a PCB manufacturer, there are many of these all over the UK and abroad, getting a single sided single layer PCB manufactured (made up to your design pattern,masked, etched and drilled ready for through hole soldering) will only take them about 1 hour from start to finish, however there is a backlog on small orders that they always take time to get through between large orders.....so from ordering to receiving in the mail will take up to 2 weeks....

your components will probably end up costing about £60.00 and the PCB will probably end up costing £25 -£40 depending on the type ordered.....you will also need a few electronics tools, but not overly many...

 

[Nicola Paton]

I would be looking to take this as far as I could. I'm quickly learning the python language and have started creating sequences. ( i.e having a lockdown button by the side of the bed that locks the doors, sets the alarms and turn the cameras to night vision or setting an alarm that opens the curtains plays the radio and turns the kettle on,etc...) if I creat a nice looking web page and maybe a phone & tablet app.

I have looked into controllers like before and the most advanced I've found is control4 and a controller cost £800, never mind the extras. If I can build the same with a controller that costs £25, it's worth a go.


I understand I might need some parts made and may need professional help, but the advantages could be great for my house.

 

[monkeyelectric]

I would be looking to take this as far as I could. I'm quickly learning the python language and have started creating sequences. ( i.e having a lockdown button by the side of the bed that locks the doors, sets the alarms and turn the cameras to night vision or setting an alarm that opens the curtains plays the radio and turns the kettle on,etc...) if I creat a nice looking web page and maybe a phone & tablet app.

I have looked into controllers like before and the most advanced I've found is control4 and a controller cost £800, never mind the extras. If I can build the same with a controller that costs £25, it's worth a go.


I understand I might need some parts made and may need professional help, but the advantages could be great for my house.

I don't know that much about the raspberry pi but it looks like a great little piece of kit for home automation, by the looks you could use products like from a company called LightwaveRF and control everything via radio frequency, have a look at their website, they have light switches, sockets, relays etc, and then also integrate media into the program too, this is something i want to look into

 

[plugsandsparks]

Have you tried using a forum for Raspberry Pi, would imagine this has been cracked by now,

 

[grantr37]

I would be looking to take this as far as I could. I'm quickly learning the python language and have started creating sequences. ( i.e having a lockdown button by the side of the bed that locks the doors, sets the alarms and turn the cameras to night vision or setting an alarm that opens the curtains plays the radio and turns the kettle on,etc...) if I creat a nice looking web page and maybe a phone & tablet app.

I have looked into controllers like before and the most advanced I've found is control4 and a controller cost £800, never mind the extras. If I can build the same with a controller that costs £25, it's worth a go.


I understand I might need some parts made and may need professional help, but the advantages could be great for my house.

If you get "professional " help on this it will cost you thousands, there's a lot more to building projects like this than a lot of people think....


I have helped a lot of people with projects who have asked on here and elsewhere, I have also helped people do University projects and got a person from this website through a college course by doing all their coursework for them, when they passed I got a 3 word email from them that did not include the word thanks......I now tend to only help out when I think it is going to benefit a self employed person or a small business as it takes quite a bit of time up and the usual response is that they get the information and help that they need then either ignore me completely and just say "Blah whatever I know better" and do what they want anyway, or they get what they want done for them then they disappear from the forum and don't even say thanks for the effort...

 

[gnuuser]

solid state relay is probably the way forward. but as said before, best get an electrician to do the 230V bit.

use an ssd between the raspberry and a contactor the reason being is the contactor can induce a feedback voltage that may possibly harm the raspberry.
the ssd is an opto-coupled relay device so there is no chance of feedback
the contactor will handle the 230 volt easily and can be operated with a 12 volt or 24 volt coil.
your ssd's can easily handle that and is easily controlled by the 3 to 5 volt output of your raspberry or arduino