I am recently new to building remote controls, I have a good understand on how electronics work, My question is, I have a Futaba (FP-R127DF) I would like to have it control a relay rather than a servo. My problem is that when i connect the + and - wires to a motor, i can not get the motor to shut off, I see it has a signal wire which I am sure it tells the receiver where the servo would be located and when to shut off. Is there away to convert the the receiver in order to have it control a relay.


EE Jason

I dont think that it is the receiver that you should modify.
Its the receiver that sends the signal to the servo, and tels it where to be.
There is always power to the + and -

Just buy a cheap relay or Electronic Speed Control for your motor, and plug that into the receiver

SJN thank your response, but i am afraid that you are going to have to treat me like i am stupid on this one, Here is what I did I bought a cheat relay, the coil is 5 volts. When I connected the +/- to the terminal for the coil on the relay, it just stays on the whole time, no way to turn it off, When it comes to motor controls I have a good understaning of how most of them work, But for remote controls and servo and the accessories that can go along with them I am not sure of what is out there to help with different situation. Are you telling me that there is a device that i can plug into the reciever that will allow me to turn a relay on and off with the tramitter even with the signal wire being utalized. I'm not sure if this helps but i have a transmitter and receiver that is used for aiplanes.

and again thanks for you response EE Jason

EE Jason,
The (+) and (-) lines are always 'hot'. The third wire and the (-) are the signal circuit. Just connecting a relay to the (+/-) lines won't work, as you found out, unless you have a relay that can be 'pulsed' on/off (good luck there!).
There are devices that are made to do just that, are an add-on to the transmitter, and that send a 'coded' signal to more than one device connected to one servo slot on the receiver (pulse width and polarity kinda thingy). Another simple way of doing the same thing for us 'cheap' people is to just use a servo and a 'micro' switch. The servo 'taps' the micro-switch's lever on'off, or holds it down till released, depending on the switch and function.
- 'Doc

PS - Using an 'air' radio for 'surface' control isn't exactly the best idea in the world (also illegal) cuz of the possible consequences. As in your causing a crash and the airplane guy chasing you with bodily harm in mind. Doesn't mean that 'air' radios are impossible to use for surface stuff, just a very bad idea...

LOL I did not know it was illegal maybe there are few things i should lean more of about rather than just building things, so there are other type of remotes that i can buy that should not give me a problem. Ill have to go and check that out, thanks for you help, and for the usefull information about the Illegal stuff.

Jason

Just wanted to let you know i did figure away out to use the servo to control a relay, should have figure it out before somthing so simple, use a limit switch that has a lever and the turn table on the servo make a knob on it so when it rotates it pushes the limit switch and can use one on either side so by rotating it the other way will turn another relay on, I found out that a ground controller would still give me the same problem, but guess that is solved now, Thanks for yall help in pushing me in the right direction,
In case you were wondering what i am bulding it is senior project for My engineering degree, i am building a submarine, that has a 25lbs trust trolling motor and three air packs that I have gotten from a fire-fighter, along with two air pumbs that is cabable of pumping up to 300+ psi, it also has a dc/ac converter to control my valves. Right now i am debating on having two different tanks in it so i can use them to adjust the weight for the sub which will help in keeping the submarine level, i was thinking of useing mercery level switches to help in adjust for the tilting of the submarine.

The submarine will only be able to submerge only if certain condition are met, some are, that it has 300+ psi in the tanks and if it is to lose signal from the controller it will rise or if it is to lose power in the sub it will also rise. WElP again thank Yall for you help