Any EE's here? Question on transmitting a wireless signal.

[AgaBoogaBoo]

Is there a site that can give a basic guide on how to create a circuit to transmit a wireless signal and then receive it? Maybe something as simple as transmitting the number 20, and then having another circuit that can receive it and display it on a screen.

I want to make one to test a few things with... any thoughts? The simpler, the better, something like a wireless door bell would be great if it can be modified to transmit a number instead of just activating the speaker.

Edit: If there's something already built, that's fine too, but I'm looking for something that could maybe be modified at some point for a custom application.

 

[Crusty]

If you are looking for something with some decent bandwidth and/or range then you are probably going to want to buy a wifi chip/board from someone like TI. I know TI has a set of boards you can buy with an FPGA on board that you can interface with via USB.

 

[Analog]

Well, you certainly opened up a can of worms... There are a myriad of ways to do this. For instance, you can use a basic TV remote circuit in RF or IR. You can use a simple PIC microcontroller's serial output to an FM transmitter circuit and vice versa on the receiving end. You'll have to know some basic assembly language or C to program the device. Here is a link:
http://www.microchip.com/stell...S_GET_PAGE&nodeId=1488

The transmitter / receiver kit is $135 with full compiler, and if you're a student, you'll get an additional 30% off from microchip if you use a .edu e-mail address.

IF you want to get real basic, you can use a simple automotive door remote kit like the ones here: http://store.qkits.com/textcategory.cfm/RF
Although those aren't real flexible, you're looking under $30

In addition, here is a good resource:
http://www.electro-tech-online.com/

 

[Colt45]

Are you better at software or hardware?

 

[jmcoreymv]

http://www.sparkfun.com/commerce/categories.php?c=16

Depending on what speed/distance you need you can get a tx/rx wireless pair for as low as $9.

 

[Modelworks]

I would start with IR communication to learn how to modulate a signal so that you can send things like numbers or text with rf.
IR is much more forgiving to learn with than RF.

The transmitting part is trivial compared to learning how to encode the message so it can be sent and received.

 

[abracadabra1]

Originally posted by: Modelworks
I would start with IR communication to learn how to modulate a signal so that you can send things like numbers or text with rf.
IR is much more forgiving to learn with than RF.

The transmitting part is trivial compared to learning how to encode the message so it can be sent and received.

My final design project revolved around encoding/encrypting/sending/receiving/decrypting/decoding a 20 bit signal. Though it was only 2 short years ago, I vaguely remember using two radio transmitters a sender/receiver. I'll see if I can dig up the report.

It's funny how quickly you forget what you learn in college. Doing something completely unrelated to your major after graduation doesn't help either.

 

[AgaBoogaBoo]

Originally posted by: Analog
Well, you certainly opened up a can of worms... There are a myriad of ways to do this. For instance, you can use a basic TV remote circuit in RF or IR. You can use a simple PIC microcontroller's serial output to an FM transmitter circuit and vice versa on the receiving end. You'll have to know some basic assembly language or C to program the device. Here is a link:
http://www.microchip.com/stell...S_GET_PAGE&nodeId=1488

The transmitter / receiver kit is $135 with full compiler, and if you're a student, you'll get an additional 30% off from microchip if you use a .edu e-mail address.

IF you want to get real basic, you can use a simple automotive door remote kit like the ones here: http://store.qkits.com/textcategory.cfm/RF
Although those aren't real flexible, you're looking under $30

In addition, here is a good resource:
http://www.electro-tech-online.com/

I can program in C and so I'm going to probably get that kit, it looks like what I need. I think I'll have a friend help build the circuit for it though, I know nothing about that stuff

Edit: They give schematics, the bill of materials, everything! This is perfect...

 

[AgaBoogaBoo]

Originally posted by: Colt45
Are you better at software or hardware?

Software, I can plug things into a breadboard if I'm told where and what to use, but that's like playing with lego's

Modelworks - is there a kit for that or something to tell me how to get started? I don't know *anything* at all about the hardware side of things, just programming.

 

[AgaBoogaBoo]

Originally posted by: abracadabra1

Originally posted by: Modelworks
I would start with IR communication to learn how to modulate a signal so that you can send things like numbers or text with rf.
IR is much more forgiving to learn with than RF.

The transmitting part is trivial compared to learning how to encode the message so it can be sent and received.

My final design project revolved around encoding/encrypting/sending/receiving/decrypting/decoding a 20 bit signal. Though it was only 2 short years ago, I vaguely remember using two radio transmitters a sender/receiver. I'll see if I can dig up the report.

It's funny how quickly you forget what you learn in college. Doing something completely unrelated to your major after graduation doesn't help either.

If you can, that would be amazing, right now I just want to send the signal and receive it (part of a proof of concept for an idea) and then later on, encoding/decoding might become a part of it

 

[PottedMeat]

I really suggest getting a kit with RX/TX modules or transceivers. They should have tutorials / etc. for basic operations.

I've used Cypress USB to Wireless modules and they're pretty easy to use. Why they call them USB-Wireless I don't know, all they do is turn SPI communcations to a 2.4GHz signal.

Doing it from scratch ( fine pitch SMD ICs, Rs Ls and Cs, and custom boards ) without test equipment can drive you insane.

 

[AgaBoogaBoo]

Originally posted by: PottedMeat
I really suggest getting a kit with RX/TX modules or transceivers. They should have tutorials / etc. for basic operations.

I've used Cypress USB to Wireless modules and they're pretty easy to use. Why they call them USB-Wireless I don't know, all they do is turn SPI communcations to a 2.4GHz signal.

Doing it from scratch ( fine pitch SMD ICs, Rs Ls and Cs, and custom boards ) without test equipment can drive you insane.

RX/TX - does that just mean receiving/transmitting? I'm not familiar with all the terms yet.

http://www.microchip.com/stell...S_GET_PAGE&nodeId=1488 - would that be something like what you're talking about?

Edit: Looking around for an Atmel version of that product, some of my friends have worked with their things and so if I need help, might be easier to use an Atmel product

 

[Colt45]

Originally posted by: AgaBoogaBoo

Originally posted by: Colt45
Are you better at software or hardware?

Software, I can plug things into a breadboard if I'm told where and what to use, but that's like playing with lego's

Modelworks - is there a kit for that or something to tell me how to get started? I don't know *anything* at all about the hardware side of things, just programming.

microcontrollers then... AVR or PIC, you can get C compilers for them both, and then buy some of the little transciever modules for them. that would be all software pretty well.

What are your input and output going to be? like.. where do you key in the 20, and where do you want it to show up?

 

[AgaBoogaBoo]

Originally posted by: Colt45

Originally posted by: AgaBoogaBoo

Originally posted by: Colt45
Are you better at software or hardware?

Software, I can plug things into a breadboard if I'm told where and what to use, but that's like playing with lego's

Modelworks - is there a kit for that or something to tell me how to get started? I don't know *anything* at all about the hardware side of things, just programming.

microcontrollers then... AVR or PIC, you can get C compilers for them both, and then buy some of the little transciever modules for them. that would be all software pretty well.

What are your input and output going to be? like.. where do you key in the 20, and where do you want it to show up?

As of now, whatever is the simplest, maybe just something in the code for the "input". To display it on the output, how should I do that? Maybe turn on some LED's that show it in binary format?

As in, maybe 5 LED's, where it would be 10100 with 1 being on, 0 being off.

 

[Colt45]

Yeah, that would be the easiest. Maybe use some 7-segment led displays if you want to be a bit fancier, and decode them in the software.

 

[bobsmith1492]

http://www.digi.com/products/w...bee-series2-module.jsp

 

[Rubycon]

What's the application? How far? Security required etc?

There's a plethora of cheap everyday things that can be altered to do this without starting from scratch.

 

[AgaBoogaBoo]

Originally posted by: Rubycon
What's the application? How far? Security required etc?

There's a plethora of cheap everyday things that can be altered to do this without starting from scratch.

Application? At some point, it will need to transmit a number and two letters, that's all.

Distance? 1 mile would be excellent for an end goal. I don't know how the FCC regulation works (another stage of this project), but if you know of a frequency that can send signals a mile in distance reliably that isn't under regulation, that would be perfect.

Security? Haven't gotten into that part yet, but it will be a concern. The device that receives this signal should only receive it from what we send, not someone else's fake signal meant to mimic our's, but have different data.

 

[Modelworks]

Some things to read:
http://ww1.microchip.com/downl...en/AppNotes/01064A.pdf
http://ww1.microchip.com/downl.../en/AppNotes/00657.pdf

They both have well documented code.

I would start by building this :
http://www.xs4all.nl/~jwasys/old/diy2.html

It can help tons when you want to see what is going on with the various bits.
For the low cost of it , its really great how useful it is.
I used that circuit to develop some related stuff a while back.

If you really want to focus on the software side of things and not the hardware then I highly recommend Parallax.
http://www.parallax.com/

The stuff is not as cheap as you could build it with parts, but what you are paying for is basically modules that can be connected together to form the end product. They have a whole range of stuff that is very well documented for beginners.


Edit:
If you are wanting distances of 1mile the cheapest and easiest way is from xbee.
Its a well documented part and has reached as far as 1.5 miles with directional antennas.
http://www.digi.com/products/w...pro-series2-module.jsp

The xbee also takes care of the FCC stuff for you.
You just need to download the manual and follow it to comply.

 

[AgaBoogaBoo]

Wow, thank you very much, I've got a lot of reading to do.

 

[abracadabra1]

Originally posted by: AgaBoogaBoo

Originally posted by: abracadabra1

Originally posted by: Modelworks
I would start with IR communication to learn how to modulate a signal so that you can send things like numbers or text with rf.
IR is much more forgiving to learn with than RF.

The transmitting part is trivial compared to learning how to encode the message so it can be sent and received.

My final design project revolved around encoding/encrypting/sending/receiving/decrypting/decoding a 20 bit signal. Though it was only 2 short years ago, I vaguely remember using two radio transmitters a sender/receiver. I'll see if I can dig up the report.

It's funny how quickly you forget what you learn in college. Doing something completely unrelated to your major after graduation doesn't help either.

If you can, that would be amazing, right now I just want to send the signal and receive it (part of a proof of concept for an idea) and then later on, encoding/decoding might become a part of it

Out of town for the weekend. Can't access my backup drive until Monday. If it's still there, I'll definitely send it your way. Digikey is a great site for finding a wide variety of parts.

 

[DanFungus]

Originally posted by: Modelworks
I would start by building this :
http://www.xs4all.nl/~jwasys/old/diy2.html

It can help tons when you want to see what is going on with the various bits.
For the low cost of it , its really great how useful it is.
I used that circuit to develop some related stuff a while back.

Wow, that's awesome. I've been having to go on campus for the scopes and logic analyzers, but this will make it so much easier. Thanks!

 

[bobsmith1492]

Originally posted by: DanFungus

Originally posted by: Modelworks
I would start by building this :
http://www.xs4all.nl/~jwasys/old/diy2.html

It can help tons when you want to see what is going on with the various bits.
For the low cost of it , its really great how useful it is.
I used that circuit to develop some related stuff a while back.

Wow, that's awesome. I've been having to go on campus for the scopes and logic analyzers, but this will make it so much easier. Thanks!

Careful with that guy; don't want to blow out your parallel port!

 

[Leros]

Originally posted by: bobsmith1492

Originally posted by: DanFungus

Originally posted by: Modelworks
I would start by building this :
http://www.xs4all.nl/~jwasys/old/diy2.html

It can help tons when you want to see what is going on with the various bits.
For the low cost of it , its really great how useful it is.
I used that circuit to develop some related stuff a while back.

Wow, that's awesome. I've been having to go on campus for the scopes and logic analyzers, but this will make it so much easier. Thanks!

Careful with that guy; don't want to blow out your parallel port!

Could you modify the design to throw in a few resistors and reduce your chances of failure?

 

[herm0016]

or you could optically isolate the inputs and outputs?

you should look into packet radio. their are hand helds that do this now, i have seen them hooked up to a gps and carried in packs for tracking search teams automatically. usually runs on 2m ham frequencies. this will get around any fcc stuff as long as you have a technician class license ( easy to get, just a 30 question test on very basic radio operation and manners)