Hi guys,
wondering if some one could help me with a simple circuit as i'm a complete idiot when it comes to electronics..
what i need is a wireless switch that can commute a on/off signal with a range of 0-30cm and low pwer consumption..
any ideas??
Thanks
What country are you in?
In most of the world building even a low power transmitter like this is illegal.
?? think you may have miss understood, i need to turn something on/off over a very short range RF30cm max, not SW RF... IR won't work for me as there will be no line of sight.
i want to keep it short range so that multiple devices working in close proximity do not affect each other..
as for legalities you're probably thinking about broadcast signals which require a broadcasting license in many countries,, not something i'm looking for.. my cell phone already has a FM transmitter, nokiaN96 (from Israel) which would be Illegal if I was back in the UK.
as for legalities you're probably thinking about broadcast signals
No I am not.
In the UK it is illegal to communicate over any distance using RF, without:-
The fact that the range is very small does not affect the legality in the UK.
I believe in the US there is an exception to this for short range transmissions but not in the UK and most of the rest of the world.
ok to keep it really simple,,
do you know how i can wire this component http://shop.snootlab.com/lang-en/parts/147-transmitter-rf-434-mhz.html to transmit a on off signal
to this component http://shop.snootlab.com/lang-en/parts/145-receiver-rf-434-mhz.html and have it out put on on/off signal
??
VirtualWire library
thanks AWOL but I wanted to wire it without going through a controller board/circuit.. just a real simple on/off singnal
Those RF boards look like a very nice "toy" that I must have.
@drippygarry
I hope you read the datasheet of the Transmitter and Receiver board. They are design to use a microcontroller, because it transmitted/received a series of bits in a serial manner. So use them "as is" is not going to work, like just putting a 1/0 signal at the data line, but eh!, you can experiment and see what happen...
Like this : Connect the +5, GND , a swith with a 10 K pull-up resistor connect to the DATA line and an Antenna wire, Do the same at the receiver end , except monitor the DATA line at the receiver.... Eh ! it might work... or NOT.... That is call "Experiment and see what happen"
I did not know in the UK you are not allow to have any kind of transmitter ( small ) example : tiny FM transitter connect to the iPod and received it in your car FM radio. An XM radio has that feature.
I believe in the US there is an exception to this for short range transmissions
I check the FCC/CRTC for that.
Techone:
I did not know in the UK you are not allow to have any kind of transmitter ( small ) example : tiny FM transitter connect to the iPod and received it in your car FM radio. An XM radio has that feature.
You are not allowed to use unlicensed transmitters. Licensed ones are fine. I have loads of them.
Devices approved by UK Deptpartment of Communications... Got it !
Techone:
@LurchDevices approved by UK Deptpartment of Communications... Got it !
I was wondering the same. Now I understand.
Grumpy_Mike:
as for legalities you're probably thinking about broadcast signals
No I am not.
I believe in the US there is an exception to this for short range transmissions but not in the UK and most of the rest of the world.
I think in US it's a power/distance thing. Alot of small racetracks don't have to be FCC licensed operators as long as they stay under a certain broadcast power and/or don't exceed a certain distance from the antenna.
You are not allowed to use unlicensed transmitters. Licensed ones are fine. I have loads of them.
Until about three years ago the small FM transmitters for the car / iPod were illegal. Now they are not providing they have type approval. That is they have been submitted to tests by an official test house and meet all the standards. This costs something like £1000. If I were to try and make one my self that would be illegal.
As a licensed radio ham I am permitted to construct transmitters for the ham bands however, but that would not cover the FM broadcast bands.
Until about three years ago the small FM transmitters for the car / iPod were illegal. Now they are not providing they have type approval. That is they have been submitted to tests by an official test house and meet all the standards. This costs something like £1000. If I were to try and make one my self that would be illegal
Let me get this straight... Let say I built a "mini/micro FM/CB band transmiter of low wattage ( well under let say 20 mW to 100 mW ), in UK that will be illigal ? In USA/Canada is not.
As for the OP, a mini/micro FM transmiter/receiver may work, it simply need a modulation ( an old Modem standard ) using 2 audio frequency - a 1 = 2 kHz tone, a 0 = 1 kHz tone. At the receiver, need a demodulator to get the 0 and 1.
Or
A ultrasonic tone as a carrier, modulated a tone to represent 2 state, use a ultrasonic receiver to get the tone being received.
My other 2 cent
Edit:
I just think of something... you can use a toy remote/receiver for what you need. It already have aa 2 state modulator/demodulator , and the motor control out can be use for your on/off switch.
Just a crazy idea
Let say I built a "mini/micro FM/CB band transmiter of low wattage ( well under let say 20 mW to 100 mW ), in UK that will be illigal ?
Yes that would be illegal in th UK and most of the rest of the world.
not sure how old this is
@magnethead794
Very interesting reading, a bit hard to understand, and I notice Canada - USA has the same ( almost ) regulations. I guess my example of a DIY tramsmitter of 10 mW operated at 27 MHz is just fine - Most RC toys used that frequency. And I was thinking about a bluetooth transmitter ( the one connect to a PC / Arduino shield ) fit under Part 15 of the FCC / Industry Canada rules, and I guess the PC bluetooth as it's FCC stamp. I am not to sure about the bluetooth shield from Itead... I did not see a FCC stamp. I guess using a bluetooth shield will be illegal in UK or any DIY tiny ( under 10 mW ) transmitter... 
Bummer !
Sorry to be off topic.
As for helping the OP, I think using a RC toy transmitter / receiver might work.
Techone:
@magnethead794Very interesting reading, a bit hard to understand, and I notice Canada - USA has the same ( almost ) regulations. I guess my example of a DIY tramsmitter of 10 mW operated at 27 MHz is just fine - Most RC toys used that frequency. And I was thinking about a bluetooth transmitter ( the one connect to a PC / Arduino shield ) fit under Part 15 of the FCC / Industry Canada rules, and I guess the PC bluetooth as it's FCC stamp. I am not to sure about the bluetooth shield from Itead... I did not see a FCC stamp. I guess using a bluetooth shield will be illegal in UK or any DIY tiny ( under 10 mW ) transmitter...
Sorry to be off topic.
As for helping the OP, I think using a RC toy transmitter / receiver might work.
Bluesmirfs from sparkfun are FCC certified. Although the RP-SMA (what I'm using) clearly says online that the FCC is invalid because you can use a post-connection amplifier to exceed the FCC regs.
You can use 2.5GHz up to 500mW ERP and be within FCC Guidelines, There are 4 channel assignments. 10mW units can be hacked from X10 camera gear. Video section is dc to 10.7 MHz bandwith and the 2 audio channels are good to 50KHz. Check the RC airplane forums, we use a ton of 2.4 gig gear in FPV.
Hav a look for something like these
http://secure.oatleyelectronics.com//product_info.php?products_id=747&osCsid=bf560d45281cc90a377753bdb09bb029
Sparkfun have similar
Go here for a working system
http://arduino.cc/forum/index.php/topic,37354.msg275923.html#msg275923
looks like the pictures are no longer around
http://arduino.cc/forum/index.php/topic,7769.0.html
Grumpy_Mike:
You are not allowed to use unlicensed transmitters. Licensed ones are fine. I have loads of them.
Until about three years ago the small FM transmitters for the car / iPod were illegal. Now they are not providing they have type approval. That is they have been submitted to tests by an official test house and meet all the standards. This costs something like £1000. If I were to try and make one my self that would be illegal.
As a licensed radio ham I am permitted to construct transmitters for the ham bands however, but that would not cover the FM broadcast bands.
Errr last time I looked England ,the states ,Australia ,SouthAfrica and other Commonwealth countries and many more countries have public frequencies on which you can transmit without any licence .
CB 27Meg and UHF are examples - RF hobby channels and I think the little transmitter /receiver pairs we use here .
Looks like he wants to be a Policeman again -Ho Hum- Ello Ello , what's goin on ere then
Oh nothing ,nothing officer plod