I need to make a radio controlled robot using a transmitter and a receiver. I intend to send some sort of data wirelessly. The data can be anything that is reasonable.
(From a 50% duty cycle pulse that has 1 to 8+ pulses (1 pulse = cmd1 & 2 pulses = cmd2, ect...) , to serial data)
I really only have the parts to make simple stuff, (no IC's other than 555's or TLC5916's / TLC5940's)
There are plenty of these types of things around:
http://www.robotshop.com/ca/433mhz-high-sensitivity-transmitter-receiver-pair-rxa33.html
This can be used to send serial or any sort of pulse coded telemetry.
I need to make my own for this project & can't buy any thing at the moment..
I need to make my own for this project & can't buy any thing at the moment..
Well, good luck!
Super-simple then:
well that's a little to simple... I was thinking a few npn's, some resistors and caps. in addition I have a few pots and a 3 variable caps, also a bunch of 555 ic's
also need's to be able to transmit data up to 30 or more feet..
Also illegal not to mention antisocial..... just buy the rx tx pair.
daveg360:
Also illegal not to mention antisocial..... just buy the rx tx pair.
not in usa
If you want to have any hope of doing anything like this - I would first suggest picking up copies of Forrest M. Mims III's "Engineer's Mini-Notebooks", particularly the one on RF/Communications Projects.
If you want to be -very- successful at these kinds of projects (and not receive angry visits from angry ham-radio enthusiasts, or your local version of the FCC), you're going to need to get really familiar with analog circuit design - and you'll also want to have an oscilloscope, a frequency counter, and a signal generator (that can handle RF) available as well. Without those instruments, you'll be flying blind with your designs, not knowing what or where you are transmitting, and likely causing interference all over place (heck, even -with- those devices, you're still likely to have problems - analog design isn't easy nor very intuitive for most; RF is a whole 'nother ballgame).
As far as the 555 is concerned - while it is possible to make an AM radio transmitter with such a device, I tend to wonder how accurate an output you would get; I tend to suspect, from what I have seen of these "clever designs", that the output would be all over the place in the band - likely fairly noisy. I think it is a good hack, but not something worth putting a lot of time into.
I think doing this yourself - especially if you are asking here on this forum - is out of the question; you'd be far better off if you looked into other solutions (using available RF tranceivers, as already mentioned, for instance).
They do sell pairs with the proper frequency for your part of the world (wherever that is?); in fact, using a pair meant for one part of the world in another may get you a visit from local authorities if you try it - so do some research before you buy (if you buy). I think it has to do with overlap of the allocated frequencies with that of military, police or emergency bands.
Other options to consider:
Putting the whole question of legality aside, it is tough to imagine that a workable RF transmit/receive setup could be achieved any cheaper than these pre-built modules at $5 to $12 a pair. If money is the constraint, then custom building is not a winning proposition. If the constraint is that you must design the RF system yourself -- like for an RF engineering assignment -- then I can only suggest you have at it.
gardner:
Putting the whole question of legality aside, it is tough to imagine that a workable RF transmit/receive setup could be achieved any cheaper than these pre-built modules at $5 to $12 a pair. If money is the constraint, then custom building is not a winning proposition. If the constraint is that you must design the RF system yourself -- like for an RF engineering assignment -- then I can only suggest you have at it.
it's more along the line of "i want to do it because I want to challenge myself and learn more about the subject"
it's more along the line of "i want to do it because I want to challenge myself and learn more about the subject"
...but for the rest of us, it's more "that's a very sweet and noble sentiment, but we may be your neighbours, and we'd quite like to be able to carry on watching TV, listening to the radio, getting into our cars in the morning, using our mobile phones and our wifi"
Please don't.
I really don't think it is illegal in USA because I see
"Build-Your-Own Radio Station" kits in stores all the time...
What does the FCC say?
I'll check in a second...
I can't find where i should look... Does anyone know what the laws are for 18929 Jamison PA, USA?
Yes, and those kits have been vetted by the FCC, most likely. However, if you built one, and actually planned on using it for a radio station, you would likely have to get a license from the FCC (I don't know if any of the micro-station non-licensed or free-licensed or whatnot ever made it to implementation). As part of this licensing, you probably have to prove that your equipment runs within the legal limits, etc.
If you really want to pursue this (ie, learning RF and how to build your own transmitters/receivers, etc), then the best way would be to get in contact with your local ARRL chapter (http://www.arrl.org/).
As far as the laws are concerned, that is up to the FCC (http://www.fcc.gov/) - so, start with your local chapter, talk to a few local member (go to a hamfest - its a perfect way to start and get a feel for things if this interests you - otherwise track down your local chapter, and ask for information about the laws, etc).
Good luck. 
I found an answer for this post about an hour ago in the form of a youtube video.
Thanks for the help all!