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Need help with RF related circuit and microcontroller code, feel free to produce a colaborative instructable(or one on your own i don't mind) Answered

Hello all who cared enough to move your mouse anywhere near the link to this post and clicked (100% of you who ended up here fall into this group.) I had an idea while hovering around the limits of wakefulness and sleep. using a microcontroller, some switches, an oscillating crystal, a battery and an antenna, we make a type of transmitter that when activated plays a series of bleeps according to a code in binary (i'm thinking that when the current goes to one pin, redirect to positive of crystal for on/1 then a grounded pin for off/0) and on the receiver end, it's basically an antenna, small transistor radio locked to the frequency of the crystal (AM preferably,) a decoder chip (microcontroller) and a relay to complete the circuit so that whatever is needed to be done remotly can be done whether it be disengaging a magnetic lock, switching lights on/off remotely or even setting of fireworks remotely. thanks to all who post a meaningful reply!



8 years ago

http://www.seeedstudio.com/depot/315mhz-remote-relay-switch-kits-2-channels-p-150.html?cPath=101_103 You need to be more clear next time. ____________________________________ There is a cheaper way to go about this, but if you don't know enough it'll be really difficult: http://www.seeedstudio.com/depot/315mhz-rf-link-kit-p-76.html?cPath=101_103 interfaced to... http://www.dnatechindia.com/index.php/Tutorials/8051-Tutorial/Relay-Interfacing.html (make sure he ground shown in the schematic goes to the negetive of the wireless piece and the negetive of the 12vdc power supply)

I don't really understand this, you want to build (not too sure)? Is this a radio remote-control thing - more information? L

sorry, for the late reply, out camping with cousins (it's a good idea to make use of Saudi Arabia when you're there ;)) umm, well bluntly, it's a two part project, first part is the one that sends, without switches, it's basically a battery/power source where the negative goes directly to the negative of the crystal, the positive to 1 leg of the microcontroller, three legs of which are occupied, 1 for power in, 1 for ground, and 1 for power out, and the power out goes directly to the crystal, the microcontoller serves to simply switch direction of the current from the out to the ground at proper intervals to simulate a code. the second part (receiver) is a compact radio receiver where instead of ultimately transforming the radio waves into sound, it stops at current and the current goes to a microcontroller that will time the "bleeps" and if the number of bleeps is correct it allows power from a power supply on the receiver end to flip a relay completing the circuit basicly turning parts 1 and 2 into a complicated switch, just as Goodhart said, a garage door opener save for two differences, first, it uses radio waves instead of infrared and 2, it's just a general switch as opposed to the whole assembly including the servos and things. if there's anything you don't understand let me know and I'll try to clarify:) thanks for your input!

Thanks, iI think it was the techinical details obscuring the function. Garage door devices can work on radio too, and electronic car locks. I guess the easiest option might be to obtain an existing system, where you're transmitting & receiving data things can get a bit complicated. However, look at how RC planes work: there's more than one control operating on the same carrier frequency, you might get somewhere using that type of system? L Saudi will be pretty hot I guess?

47 Celsius at half past ten, I'll say it gets pretty hot ;) back to the topic at hand though, i've only seen a few garage doors work on radio and i thought of cannibalizing a system, but then I thought "well, that sounds like a cheat to me!" because this little project was my entry in a competition against my uncle (he's studying biomedical engineering) we were allowed to use any resource for help or inspiration but the circuit has to be original. I think I'll have a looks-y at a friend's RC plane, saved under "inspiration" and thanks again for your help, i'll post any advancements over here :)

Well, an obvious theoretical on the RC plans is: "set rudder to Xo" "set flaps to Yo", the servos that move these disengage a lock instead. Develop that and you can think of "multiple values OUT (transmitter) = multiple values OUT (receiver / decoder)", sort of what you're thinking with the coded bleeps.

47o? Phew!


Sounds very much like an oversimplified version of a garage door opener. . . or maybe not....

Yeap! more or less, but uses RF instead of IR (though i have seen some RF garage door openers, they're a rare find! thanks for your thoughts!

Hmm? Some of the door openers I have dealt with do not use IR (which requires: line of sight to use), but can be opened anywhere one is within range, lending me to think they are RF controlled.

I do know that most if not all of the key fobs used for automobile alarms and door locking systems are RF.

Of course, you could go with a UK SOUND frequency: