controling a receiver from pc

[atntias]

im working on a project to control a "rc car" from the pc, the rc car is controled by 2 servo engines
my goal is to manage to control these servos from the pc remotlly- in other words reaplace the remot control and insted use a pc.
i guss i need a transmitter but i need to know what is the best way to connect it, wich recvier shuld i get/build and what exaclly do i need the transmitter to do for it to send "commands" to the reciver.
help will be greatlly aprecited
thx sefi-

 

[Nigel Goodwin]

There are essentially two differing methods.

1) Use the original RC receiver to feed the servos, your PC then has to generate the servo pulse fed to the transmitter (you could mod the original transmitter for this!). This method basically duplicates a standard RC setup with the PC replacing the joysticks.

2) Send digital data via a radio link (probably using licence free radio modules?), you then generate the servo pulses in the receiver, probably using a PIC or similar. This method is more versatile, and you can incorporate far more features.

 

[mstechca]

im working on a project to control a "rc car" from the pc, the rc car is controled by 2 servo engines
my goal is to manage to control these servos from the pc remotlly- in other words reaplace the remot control and insted use a pc.
i guss i need a transmitter but i need to know what is the best way to connect it, wich recvier shuld i get/build and what exaclly do i need the transmitter to do for it to send "commands" to the reciver.
help will be greatlly aprecited
thx sefi-

you can use any modulation (AM, FM, FSK, whatever).

I suggest making a data link between your computer and the engines.
have the engines connected to the receiver. add a microcontroller in the receiver as well to control the engines, and whatever else.

You may need to incorporate PLL related circuits to prevent interfering devices from screwing up your engines.

as for the transmitter sending commands, it needs to send pulses that the receiver can recognize. The easiest approach is to have the transmitter transmit a high frequency tone when a logic high is sent, and have it transmit nothing when a logic low is sent. You might be able to get away with this method without a PLL, but any nearby interference (on the same station) can screw up the receiver when using this method.

good luck.

 

[atntias]

first thx u guys are being helpfull.
ok so i am going to use the orignal receiver that is made to control servos if matters it a "sanawa RX-515, FM 72MHz,5 chanel", and i have a 72MHz crystal.
wich transmitter do i need?what commadns dose he need to send?
i know the recever genretes repetitive pulse of 1ms to 2ms (1.5ms being the "neutral" middle position). but what do the transmitter need to send?and what need to be dose to the recevier for it to do that(meaning what do i have to trigger)
hope i bieng clear, sorry bout my english ;p
thx again
-sefi

 

[Nigel Goodwin]

first thx u guys are being helpfull.
ok so i am going to use the orignal receiver that is made to control servos if matters it a "sanawa RX-515, FM 72MHz,5 chanel", and i have a 72MHz crystal.
wich transmitter do i need?what commadns dose he need to send?
i know the recever genretes repetitive pulse of 1ms to 2ms (1.5ms being the "neutral" middle position). but what do the transmitter need to send?and what need to be dose to the recevier for it to do that(meaning what do i have to trigger)
hope i bieng clear, sorry bout my english ;p
thx again
-sefi

If you'e using the original receiver, use the original transmitter as well, modify it to interface the PC to it - how exactly you can do that depends on it's exact circuit.

 

[atntias]

i would but this is a school project so ineed to make the trasmitter i only have a fitting crystal for the same chanel,
i need to know few things
1.what pulses the receiver recognizes and what they do
2.wich transmitter excally shuld i build(maby the is a schematic made already that i can copy).
3.what is the easyest way to connect it to the pc (printer output/usb/other)
4.where can i read related stuff and/or info that can help me(tried google but b/c of my english skills coulndt find much ;p)

any ideas from u guys that can help me/explain things will be greatlly apreaceted.
thx again -sefi

 

[audioguru]

Are you or your teacher going to write a program for your pc?

In Google, I entered RC Servo Theory and got many links explaining the pulses that are required to control your car.

Try entering RC Transmitter Circuit in Google to see if there are schematics for one. Where are you going to find the special RF coils and things that are required?