Wireless remote control

Thread Starter

Chris15

Joined Apr 15, 2009
252
Hello, how would i make a very simple version of a wireless RF remote controll that would close a relay with one push and open it with another. If some of you remember i tried to salvage the guts out of a doorbell but failed so i was thinking of making a simple one so i can do things with a wireless remote, because once i can get a relay to work i can controll anything.






Chris
 

retched

Joined Dec 5, 2009
5,207
Well, for the remote, you would only need it to send one signal.
And the receiver would trigger a pulse when the signal is received.

Using a latching relay with the pulse (~20ms) will change states with each pulse.

So, every time the button was pressed, the relay will change states. (Open or closed)

Using a standard relay, you would need to constantly power the coil of the relay to hold it in state. That would further complicate things as well as consume more power.
 

Thread Starter

Chris15

Joined Apr 15, 2009
252
Ok yes you seem to know what you are talking about so how would i make one of these, i saw them in a movie where a man was practicing blowing squibs (fake bullets explosion) and he was holding a small circuit board with an aerial coming out so i started to wonder about wireless again.

So yes how do i do this, is there a certain kind or circuit name or do u have a schematic, thanks if u can lead me in the right direction

Note: making sure it is like this
- 2 seperate circuit boards
- one with a switch and aerial (obviously other circuitry)
- and another with a relay and the other circuit
i press the button once and the relay open, press the button again whenever i want and it closes

Chris
 

retched

Joined Dec 5, 2009
5,207
Are you making this as a prop? And are you comfortable with soldering techniques and basic safety? AND how do you feel about using off the shelf products? (Some folks want do it yourself only)
 

Thread Starter

Chris15

Joined Apr 15, 2009
252
well soldering is no problem for me, and i just wanted to make one of these because i thought they may be very simple to make
 

retched

Joined Dec 5, 2009
5,207
Ummmm.. Simple, no. Not even close.

Take a look at this:
http://www.rentron.com/Linx/RELAY_MOD.htm

Its a IR reciever that can open and close 4 relays.
IR communications deals with a lot of different disciplines of electronics to get right.

You need to know quite a bit to build one from scratch.

If you are DIE HARD, I WANT TO BUILD IT! Then I would start from the beginning of the book at the top of the site.

It will get you the know how to understand whats involved.

You will also need specialized equipment for reading your produced signals to be sure your transmitting what you think you are, and to be sure the garage door doesn't open or close with the interference it may produce.
 

retched

Joined Dec 5, 2009
5,207
Then again...There are kits available to do this sort of thing if you don't want to do the designing and just build the kit.. They are a good way to learn.

So what do you prefer?
 

Thread Starter

Chris15

Joined Apr 15, 2009
252
ok i like hassan's ideas, i had thought about them, could you explain the doorbell, relay, and battery one a bit more, how do you mean output, the speaker wires, and put the battery in between
 

retched

Joined Dec 5, 2009
5,207
Take the speaker out. Use a meter to find out the voltage and current when the button is pressed. So now you know how much power you have to work with. It will be very small, but, you can use a transistor to beef it up enough to activate the relay.
 

Steve C

Joined Nov 29, 2008
88
If off-the-shelf is OK, you really need to look at keyless entry systems on eBay. You can pick up a system for as little as $10 or $20 for a 1-2 channel system. Operates on 12 volts, the output is already via relay contact, and if you want to bring it into the house, a 12V wall wart will do the trick, also a buck on eBay. No problem switching 120VAC through the relay contacts in the automotive relays. And the remote controls of course will be small and portable and most importantly, programmable and replacable.

For a little more money, you can buy a system that will have 8 channels of communication in one remote.

For a little more money on top of that, you can find 2-4 channel systems with 2-way communication so the remote will tell you when relays are switched on and off.

And for a little more money on top of that, you can communicate via wifi or GSM so you can dial into your relays via smartphone and turn them on and off, of course with 2-way communication.
 

Thread Starter

Chris15

Joined Apr 15, 2009
252
ok so it is 2 volts, roughly it lights a LED, so how do i beef it up to click the relay, and how do i latch it with one press, then unlatch with another press?
Chris
 

retched

Joined Dec 5, 2009
5,207
You need to get yourself a LATCHING relay. Logic level coil would do nicely. Latching relays latch with one pulse and un-latch with the next.

Now depending on what you want to operate with the relay, will depend on the relays load rating.
 

Thread Starter

Chris15

Joined Apr 15, 2009
252
Ok
So is the LATCHING RELAY just like a normal relay, just with extra pins, a small box, and how would i use a transistor and what type to boost the voltage, if u could can u post like a quick simple schematic like off paint or something of what you are talking about, i will just learn easier

Thanks, Chris
 

Thread Starter

Chris15

Joined Apr 15, 2009
252
is this the relay you are talking about?>

http://media.digikey.com/photos/Panasonic Photos/DSP COIL LATCH RELAY- DPST.jpg

it is just one small blck box and it consists of 2 relays inside? i am not farmillia with a LATCHING RELAY as a single unit, could you please explain in more detail of how you wire this thing up.

you stated that one pulse will latch it and another pulse will unlatch it, and i need to boost the voltage with a transistor, what sort of transistor will suit this apropriatley and how does the wiring with the transistor and the relay look

Chris
 
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