low voltage motor that will open a switch

[scottknightus]

I plan to build a remote control unit that will simply activate a spring loaded trigger.  I don't need a servo because I don't need continual control.  I just need to move a spring loaded release or trigger.  I have found a transmitter, a receiver and plan to  connect this to a relay that will move a motorized or spring loaded arm that will activate my unit on comand.  Are there any affordable low voltage motors that can be activated by a relay?  I only need a transmitter and receiver that work at about 200 yards max..

[Admin]

hmmm you cant just hook up a motor to a reciever. the reciever emits a low power squave wave, so you would need to build a circuit to convert that wave into something useful for a dc motor. would be best just to use a cheap servo. the hitec HS-311 is like $9 . . .

[polar bear6]

what you can do, is replace the motor in the servo with a solenoid, i haven't tried it but it should work.
you get solenoids in electrical typewriters, its the thing that pushes the letter "mold" thingy on the inkroll then it gets on the paper.
a little bad explaining but think about it for a wile then you will understand.
the solenoid are not in the typewriters with the golfball thing, look for typewriters with a weel full of letters.

[scottknightus]

Doesn't a relay that would normally link the receiver to a buzzer or bell create a usable voltage that could be used to  run a cam or motorized switch?  The reason I don't want to use a servo is that the transmitter is so big.  Even the smaller units have more controls than I want.  I'm looking for a transmitter that functions like a remote door lock on a car.

[Admin]

well you still need to power the relay too . . .

the 200yd range really limits you to the more expensive transmitters.

[scottknightus]

I don't mind the expense or having to power the unit.  I just want the transmitter small enough to hold in one hand.  Are there any small servo transmitters without x and y axis joysticks that I could use?  I just need a on/off button to activate the servo or whatever will trigger the unit. 
  Thanks for your paitience; I'm new at this and I don't have the knowledge base to communicate my needs.

[Admin]

Hmmmm yea I dont think they make any that are single button devices.

This is the smallest I can find:
http://www.servocity.com/html/3_4-ch_neon_fm_systems.html

You could consider hacking it open, taking out only the components you need, and putting the components into a smaller box. I have opened up a transmitter before and they have tons of wasted space in them. The joystick can be replaced with a button, too.

The less attractive option (because I couldnt find any available to buy):

You might want to consider making one . . .
http://www.uoguelph.ca/~antoon/circ/tx15trak.htm
http://www.discovercircuits.com/R/rftrans.htm

All you really need to do is have the transmitter button release a high powered EMP that can be detected by a reciever.

The reciever would then flip on a MOSFET (http://www.societyofrobots.com/electronics_advanced_components_tutorial.shtml#mosfet) that would drive a solenoid (http://www.societyofrobots.com/actuators_solenoids.shtml).

I have never built a transmitter/reciever system so I cant really help . . . sorry!