Already searched, micro rf transmitter/reciever need gurus

very small rf transmitter

Hello, I have a small school project. Relatively simple but need help in deciding which receivers and transmitters to look at.

I'm trying to make an extremely small keys locator for a project. So I really need a very basic function. Click on the base and the reciever emits sound and flicks on led lights. The lights and sound I can take care of, but the rf stuff I'm not too keen on. For example what kind of technology should I be looking at specifically?

If any of you have some suggestions/help for me, I would be extremely thankful.

Here are the requirments;
micro, less than a cm in width for reciever
Reciever is hopefully already setup with battery
Transmitter is very small hopefully about the same size
50ft range


The pieces are extremely cheap

Again thanks for those who respond, if you have any ideas/suggestions please let me know.

Ivan.

Re: Already searched, micro rf transmitter/reciever need gur

Please try ASK transmitter and receiver module.

Re: Already searched, micro rf transmitter/reciever need gur

you da man... looks like the stuff im looking for.

Thanks alot.

Ivan.

Re: Already searched, micro rf transmitter/reciever need gur

Let me give you a friendly advice

1.) Don't intend to build the module itself because it's very, very time consumming. Also, many equipments are required. Build yourself a nice demo unit for the idea. ( Idea counts the most ! )

2.) If you live in Europe then try 433Mhz because this is the ISM band in Europe and most European countries allow radiators to operate in this frequency band as data transmission. ( There is slightly variation in between countries ) For US, both 315MHz and 433MHz can be used.

3.) In the your report, you can add a section to explain the reason of choosing this transmitter.
i.) Reason to choose ASK rather than FSK
ii.) Reason to choose 433MHz or 315MHz. ( Depending on National standard )

in Europe : ETSI
in US : FCC

4.) Take care of antenna length otherwise walk range won't achieve.

Roger

Re: Already searched, micro rf transmitter/reciever need gur

The info ya sent me was very helpful. By making a demo unit, u mean use an already made rf modules and just add some tech to them to do what I need them to?

Ivan.

P.s. anyone see any design layouts using these to essentially make a remote on/off switch?

Re: Already searched, micro rf transmitter/reciever need gur

Hi Ivan,

Yes, please use existing rf modules unless there is Spectrum Analyzer and Communication testset. Because the purpose of rf link is for cable replacement only ( although not exactly in real life ). Then design the rest of the circuit.

e.g) Your transmitter may need to link up with a no. of key locators. So that a unique code is required for each of them.


Roger

Re: Already searched, micro rf transmitter/reciever need gur

Hey Roger, do you know rf module prices really well? Know what brand I should look at that's really cheap, yet effective. Ie. range of 25m-50m, still has to be small though...

Ivan.

Re: Already searched, micro rf transmitter/reciever need gur

Hi Ivan,

I have no idea what's available at your local shops. But you can try the following website. There is quite a bit of information. ( make sure you check ' Application note ' & ' Regulation ' )

www.rfm.com

The modules are expensive but it doesn't matter for school project.

Commerical products use ' Super-regen ' technology that built by discrete lump component. The ex-factory price is in the range of a few dollars in USD.

Roger

Re: Already searched, micro rf transmitter/reciever need gur

Ok, I'll make this using the tech you described. Heres a question for all though. If I already had a design that was the most efficient and cheap. How cheap could I really make this for? Atleast parts wise... 2 bucks max in parts(over 100 000 units)? I know this isn't a good question but I still need to put a dollar/cost to raw materials.

Ivan.

Re: Already searched, micro rf transmitter/reciever need gur

The cost of 1set of unit : including 1 transmitter unit & 1 receivng unit

electronic part cost : US$1.5 ( max. ) ( include rf parts, encoder and decoder etc )
mechan + packing : around US$0.6 depending on actual size and complexity
manufacturing cost : factory dependent ( including design complexity, workmenship, no. of solder pads, quantity etc. )

Comsumer electronic market is very tough becuase of extremely price sensitivity.
A difference of 10 cents USD ( or even less ) between competitors end up loss the deal.

Re: Already searched, micro rf transmitter/reciever need gur

Thanks roger, I believe this will be good enough to finish my project.

Re: Already searched, micro rf transmitter/reciever need gur

Not at all !