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need basic EE help

378 Views 10 Replies 6 Participants Last post by  greco gixxer
OK, I've been wanting to design this for awhile but due to the fact the cops just showed up after I fired ONE mortar (not to my place, but they're hovering about)...... I NEED to design a very cheap and thus expendable FM receiver that simply closes a relay contact when it gets a matching frequency input of ANY type at X frequency strength..... so simple that it costs less than $5 per unit not including the AAA battery.

I would need what.... a small battery, a Nichrome rocket ignitor to ignite the fuse on whatever it is, a transistor to complete the ignitor circuit when whichever lead gets the signal, a crystal cut to 72.530 mhZ, I would assume a diode somewhere to prevent ambient ignition at the wrong side of the circuit, knowledge on how the fuck to wire it, and I'm sure more stuff I'm missing , hopefully not TOO much. I REALLY would love to have someone help me design this ultra-cheap, expendable, simplest-possible FM receiver that just closes a contact upon receipt of any substantive signal at that frequency. AKA I push either of the sticks on my futaba helicopter radio in any direction, and all low-cost receivers receive the signal and close the circuit, firing the nichrome ignitor and lighting the fuse on whatever it's connected to.


Anyone wanna help ???????? SURELY it's doable for NO MORE than $10 per receiver, PREFERRABLY less than $5 (of course after buying all components in quantites of 100 or more, definetely not expecting that price for a one-off).
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Sonick...look up schematics on a garage door opener. That should basically be what you're after. You might have to swap in FM for whatever garage doors use (not sure) but the principle is the same, right?

##EDIT##

I've also seen doorbells for houses that don't have wiring at the door. Transmitter is a thumb-sized box that you stick on the doorframe, receiver is a fist-sized box that you place somewhere in the foyer/entry hall...it receives the signal and initiates a chime. Schematics on that should also work.
You may find some ideas/help here:

http://www.rentron.com/remote_control/remote1.htm
Illegal model rocketry?:crackup :crackup :crackup
Sonick is moving into the business of defense contracting...
H2O_Goalie said:
Sonick is moving into the business of defense contracting...

As long as he doesnt use corvette parts.:laughing :laughing
YZFRob said:
As long as he doesnt use corvette parts.:laughing :laughing
Why? Does he upset Kenny Dantley and Mr. McGrath if he does? :laughing
H2O_Goalie said:
Why? Does he upset Kenny Dantley and Mr. McGrath if he does? :laughing

No, I figured he wants to make it reliable.:laughing :laughing :laughing
Tear apart an inexpensive remote control car - all the parts are there. There are remotes to turn on Christmas lights, too. They'll be cheap now.

You could go one up and use a reusable $30 mini web-server over a wireless ethernet connection.

You might replace the fuse directly with the ignitor.
But I don't think I'd want to set up an explosive device that is triggered by a open Frequency.

That would be a good way to have a mortar go off in your face.
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