Wireless on/off switch

[AdvsNoob]

Hey im trying to make a simple wireless on/off switch that can be powered by AA battery's and i would like to make it from scratch... Sooo any help? I do have knowledge in creating stuff so maybe a list of parts? thank you!

[random robots]

you can make an ir led turn on or off, depending on the position of the switch. a phototransistor will pick that up and turn on or off your device.
all you need is:
a switch,
an ir led,
and a phototransistor

Hope this helps,
Patrick

[AdvsNoob]

I think there's more to it though, i like the idea but i would also like it not have to be pointed right at it, you know what i mean. Like have a bit of distance about 15-20ft which ir should reach but its the fact that you have to point it right at it


any schematics??


And thanks for your help btw

[random robots]

not really. all you need is a remote control circuit(switch connecting to 555 38khz ir led circuit from this link- http://www.robotroom.com/Infrared555.html and an ir reciever with output connected to your device or a transistor to turn the device on. thats really how complex it can get.

Hope this helps,
Patrick

[Soeren]

Hi,

Hey im trying to make a simple wireless on/off switch that can be powered by AA battery's and i would like to make it from scratch...

You'd be better off using either radio modules or hack a cheap wireless doorbell or similar.

Building radio equipment from scratch is quite involved and the higher the frequency, the more experience you need to get it working.
Transmitters are fairly easy though, but a receiver is harder, since you need to dig out a weak radio signal from a lot of "noise".

So, better stick to using something that allready works in the HF end.

[Admin]

If I were to do it in under 10 minutes, I'd attach a servo to an on/off switch. Then attach the servo to a RC receiver. Done.

Or buy a cheap $20 RC toy and hack the remote.

The harder fancy way would be bluetooth + mcu + MOSFET.

[madsci1016]

$9 transmitter and receiver set


never used it though.

EDIT, eh, links backwards, but you get the idea.

[blackbeard]

$9 transmitter and receiver set


never used it though.

EDIT, eh, links backwards, but you get the idea.

it's a good kit but it's not a switch. you can make it one though with an extre 75 cents worth of components (plus a microcontroler at the recieving end). all you need is a 1uf cap,a 10k resistor, a button and a 74ls14 ic.  look up how to make a schmidtt trigger oscillator using those 3 components and rig it up to the button and then to the data pin of the transmitter. this is now your remote. now use your microcontroler on the reciever side to see what frequency range you recieve when you press the button and add a few lines of code saying that when you recieve pulses within the frequencey (i set it so it would need it to stay that way for a half a second) then it will trigger whatever effects you want. this makes it really easy to make cheep remotes but it needs a microcontroler on the other end.

[madsci1016]

it's a good kit but it's not a switch.

 but it needs a microcontroler on the other end.

No it doesn't. I'll play the part of Soeren here and inform that for such a trivial task as this, no micro controller is needed.

For one thing

What the transmitter 'sees' on its data pin is what the receiver outputs on its data pin

So holding the data pin on transmitter high or low will keep the receiver high or low. The problem is they don't say what the receiver does if the transmitter is off. My guess is that it enters a high-impedance state, and floats the pin. But, that would be great, because then you could pull it down, and always have the transmitter transmit a 1 (tie TX to VCC) and whenever the transmitter turns on, the receiver would pull the data pin high. Vola, a wireless switch.

But if not, there are some clever ways to get the message across using circuits. You could have a 555 rigged to generate two different frequencies at the push of a button,  and have a filter at the receiver end to filter out the 'off' frequency, and pass the 'on' frequency to keep a cap charged holding the gate of a transistor in it's on region. That's just off the top of my head. Soeren will have better ideas i'm sure.

[blackbeard]

it's a good kit but it's not a switch.

 but it needs a microcontroler on the other end.

No it doesn't. I'll play the part of Soeren here and inform that for such a trivial task as this, no micro controller is needed.

For one thing

What the transmitter 'sees' on its data pin is what the receiver outputs on its data pin

So holding the data pin on transmitter high or low will keep the receiver high or low. The problem is they don't say what the receiver does if the transmitter is off. My guess is that it enters a high-impedance state, and floats the pin. But, that would be great, because then you could pull it down, and always have the transmitter transmit a 1 (tie TX to VCC) and whenever the transmitter turns on, the receiver would pull the data pin high. Vola, a wireless switch.

But if not, there are some clever ways to get the message across using circuits. You could have a 555 rigged to generate two different frequencies at the push of a button,  and have a filter at the receiver end to filter out the 'off' frequency, and pass the 'on' frequency to keep a cap charged holding the gate of a transistor in it's on region. That's just off the top of my head. Soeren will have better ideas i'm sure.

i admit that i'm mostly talking from my own experience but at the same time have no background info on how they are supposed to work. i found that if you hold high then it will stay low and when switched from high to low it would send a "blip" so to speek. also when left open for a long period of time it tended to go a bit wonky and spit random frequencies though these would go away once you sent something. also i just said a schmidtt trigger oscillator since it's cheeper and simpler then a 555 and works for this job (ya i know i'm cheep and a bit lazy too ). you can also make a remote that sends a bunch of different frequencies by switching resistors of various values in series and parallel to change the frequency in the same way as a 555. i'd really be interested in that filter you mentioned that doesn't involve using a microcontroler! it would make my projects simpler too!

[madsci1016]

So you have those radios? So if the transmitter is completely unpowered, what is the receiver doing?

When it's 'going wonky' have you tried pulling it low with a resistor to see if it's just going into a high- Z state?

[blackbeard]

So you have those radios? So if the transmitter is completely unpowered, what is the receiver doing?

so basicly if i have the reciever hooked up to my scope and the transmitter isn't powered or sending anything then all i see are random waves that arn't mesurable as they change frequently. it's basicly random

When it's 'going wonky' have you tried pulling it low with a resistor to see if it's just going into a high- Z state?

nope. to be fair i've never even used the datasheet since i wanted to figure it out on my own so i'm probably doing it wrong. what i did is i made it so the schmidtt trigger oscillator was sending a pulse when i wasn't inputting commands. sorry if my explanations are a bit vague and noobish. i'm going by memory and i misplaced the controller i made. i do however still have the transmitter and reciever.

[AdvsNoob]

Just so you guys know im making a custom computer case for my gaming computer and i want a wireless switch to turn on some leds, like a toggle switch, i thought it would be cool And im also selling these cases cause im mass producing them so i have to have them as cheap as it can. OH OH OH Don't worry though im printing out stickers for SOR to be place on inside of the case. I hate it when people take credit for my ideas so I'm giving the site credit for helping me with this I would just like a straight on idea on how to make it as cheap as possible please and thank you

[Admin]

In that case, Google up how those little buttons on car keys can turn on/off a car alarm. I'm sure you can probably use the same design.

[random robots]

ok. if its cheap and simple you want, get an occilator, get an led, and get an ir reciever, get a switch and youre done. all you need is be able to turn on the led running at the occilator frequency, and turn it off. the irreciever will detect if its on or off and turn on the device. if you have to flip a switch, connect the output of the irreciever to a servo controller(555 timer, micro) and connect output of that to the servo. itll probably be 4 or 5 dollers worth of parts.

Patrick

[blackbeard]

In that case, Google up how those little buttons on car keys can turn on/off a car alarm. I'm sure you can probably use the same design.

i actually saw these fob kits on electronic goldmine a while back. like just about everything there they seemed a little pricy though for what they did but for simple on off switch this might be what your looking for.

[chelmi]

This:
http://www.sparkfun.com/commerce/product_info.php?products_id=8948
and this:
http://www.sparkfun.com/commerce/product_info.php?products_id=8945

[madsci1016]

This:
http://www.sparkfun.com/commerce/product_info.php?products_id=8948
and this:
http://www.sparkfun.com/commerce/product_info.php?products_id=8945

Tisk, Tisk, Someone didn't read the thread. I linked those a while back and we have been discussing it's use.

[Razor Concepts]

I kinda think IR would be the best, it costs like... 20 cents. So you have a minor inconvenience of pointing it in the general direction of the computer, so what? Generally you are looking at your computer while switching it on and off   Also kinda why TV remotes aren't RF, because there really is no need to

[Soeren]

Hi,

I kinda think IR would be the best, it costs like... 20 cents.

Where?

Generally you are looking at your computer while switching it on and off  

Otherwise, there's no real need for LEDs coming on either 

Also kinda why TV remotes aren't RF, because there really is no need to

Some TV remotes are RF.

[madsci1016]

Some TV remotes are RF.

I actually like RF way more.