Need guidance on a simple wireless setup to transmit a number

[ankitgu]

Goal: To transmit a number from one location to another without wires. For example, the number 20, and to transmit it from one place to another.

I'm not worried about distance or anything specific like that right now, however I want to be able to change the number that is transmitted, and change how it is displayed. I think the easiest way to display it might be to have a set of LED's that display it in binary.

I'm better with the software side of things and so writing code to translate the number to binary and send a function to turn some LED's on shouldn't be hard. My issue is with the hardware, how do I get that setup? What do I use?

Setup Solution: Atmel and others seem to give schematics to get started with, I think I would just use that.

Question for the forum: What products should I use? Is there a website that has projects like this that were already completed that I can build a copy of on my own and then modify/tweak?

Constraint: I can program in C, but haven't ever touched assembly... if I can do this without getting into assembly, I'll be a happy camper.

Any thoughts?

 

[ankitgu]

By the way, I did try searching google for a project that already covers this and couldn't find it. From what I know, this should be somewhat "simple" or someone should have already tried it and posted their results. I'm probably not searching for the right thing and so any advice even just on what to search for would be appreciated.

 

[chroot]

Make sure that whatever transmitter you design uses the hobbyist band, or else you'll be breaking the law by transmitting without an FCC license.

The simplest way is probably to go to your local hobby store and buy the off-the-shelf transmitter and receiver modules. A more difficult way would be to design your own transmitter and receiver circuits using schematics that are widely available on the web or in books.

You might want to consider something like pulse width modulation, which is very easy to demodulate if you have something like a PC looking at the receiver output.

- Warren

 

[berkeman]

Are you thinking or using RF (radio frequency) transmission, or would line-of-sight optical be okay too? If you can do it with light, then you won't have to worry about the FCC regulations for not polluting the airwaves.

If you can do it with light, look into medium power infrared remote control circuits.

If you want to use RF, the as chroot says, your main two options would be to use a low power FM transmitter kit from Radio Shack or somewhere, along with a standard inexpensive FM receiver (either a kit or just a simple FM broadcast radio receiver), or to get demo boards for the 2.4GHz ISM (microwave oven) band. The low power FM transmitter route will get you about 10-20m range, but not much past that.

 

[ankitgu]

Definitely RF transmission, eventual goal might be longer distances up to a quarter mile.

chroot - thanks, I'll check out a local shop and see what they have and recommend.

berkeman - I'll start with checking out demo boards for the 2.4GHz band. I found some sites that have a lot of Atmel AVR projects and so I'm going to be scouting those.

Thanks again, and I'll post back with my results in the next few weeks for others who might run into this.

 

[berkeman]

Definitely RF transmission, eventual goal might be longer distances up to a quarter mile.

chroot - thanks, I'll check out a local shop and see what they have and recommend.

berkeman - I'll start with checking out demo boards for the 2.4GHz band. I found some sites that have a lot of Atmel AVR projects and so I'm going to be scouting those.

Thanks again, and I'll post back with my results in the next few weeks for others who might run into this.

For ISM RF transmission chipsets, you might also check out Cypress' Wireless USB chips, and Analog Devices ISM chips.

 

[ankitgu]

For ISM RF transmission chipsets, you might also check out Cypress' Wireless USB chips, and Analog Devices ISM chips.

analog.com/en/prod/0,2877,ADF7021,00.html

I found that, and it looks good, except I'm entirely confused about this.

I originally just wanted something standalone after programming so that it doesn't need a computer to activate the sending of a signal. This one seems to require a serial cable.

I'm going to have to have a friend studying EE help me put this together. Is there any kind of kit that will make this a little simpler? A lot of the things I'm finding now require assembly.

decibit.com
microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en010060
analog.com/en/prod/0,2877,ADF7021,00.html

Any idea if there's something out there that can be programmed in C? I still have some searching to do, but have spent a few hours so far without any luck.

Edit: I did find this, and think it might work: electrowave.com/index.shtml

Could someone take a look at the electrowave item and give me some feedback? I can probably find an Atmel microcontroller and have it output to serial, or at least I think I can.

Any thoughts are appreciated :)

Note: Can't post url's yet

 

[berkeman]

I'll post some of the URLs for you:

http://www.analog.com/en/prod/0,2877,ADF7021,00.html

ftp://ftp.analog.com/pub/www/techSupport/designTools/evaluationBoards/downloads/ADF7xxx_ADIismLINK_Install_Feb2008.zip[/URL]

http://www.electrowave.com/index.shtml

Many of the evaluation boards for these transceivers are made to interface to a PC. You might try searching at uC sites (like Microchip PICs or BASIC Stamps) to see if they have any uC eval boards with interfaces to ISM radios. Alternately, look for a uC eval board that has a serial port output, and just connect the uC board to the radio eval board.