Hi guys, i've decided to keep myself busy this summer by building/making some sort of electronics project. So i've decided on building my own RC car controlled from the computer parallel port, mainly because i've done parallel port projects before. For my A-level I made a robotic arm which moved using servos, the RC element will be new since never done anything that was radio controlled and I fancy a challange. So does anyone have any good links on how rc stuff works? Or any ideas I can use for this project?
Hey, got any pictures/write-up on the robot arm? Sounds interesting For my a-level project, I did a wireless signal monitoring system (I called it the 'Wireless Wire' how witty). Never again. As always there are many different ways of doing it. One that jumps into mind is to use an existing RC system (like a Futaba radio system) and using the 'Buddy Lead' (for allowing experienced pilots to train noobs) port on the back of the transmitter to send your control inputs to the receiver. I *think* the protocol for it is described in the following site: http://autopilot.sourceforge.net/pcm.html And here is a nice project that uses it (for reference purposes): http://alessioandrea.altervista.org/rcjoyng2.html A great PDF that sums the protocol up: http://graphics.tudelft.nl/~wouter/publications/pasman04b.pdf You could write a computer program to send the serial data over the parallel port to the buddy lead connection of the futaba radio. Of course, I went for this way because I have a proper RC radio system already (futaba), and although it is probably a lot more complicated than other people will suggest, it has huge expandability. One thing to bear in mind is that my system is a 6 channel plane/helicopter system. The simple 2 channel RC Car systems don't have buddy lead connections as far as i know.
Parrallax.inc do a tutorial in programming processors for rc and it looks very simple (also has a guide for turning servo into moter controllers for robots. apparently its some sort of pwm. Parrallax inc stamps in class series.
Yeah the futaba servos i used in the arm operated on the pwm pricipal, I think all servos do. Macaba, thanks for the links. Sorry i dont have a write-up of it basically how it worked was you'd have the 8 input/ouputs from the parallel port arranged like so: 1 Arm up 2 Arm down 3 Wrist clockwise 4 Wrist Anti clockwise 5 Gripper Open 6 Gripper Close 7 gripper sensor 8 arm sensor then in the program you'd type "1, 10" so the first output (arm up) circuit would switch on for 10 seconds but because you selected either 1 or 2 then the program would constantly poll the input at 8 to make sure the servos didnt make the arm go up too much or down causing the frame to break (it was only balsa wood). The same would happen in 5 or 6 were selected, that would cause the gripper sensor to become active to make sure you didnt open the griiper too much or close it too tightly. I did originally plan to use a joystick or a game pad to control it but I didnt have the time to figure that out. Although I probably would have got more marks for doing it the way I did with a I/O interface and program control.
http://www.milinst.com/animatronics/animsside.htm If your looking to repeat the previous system And i think it works as you are used to.
yeah the idea was a similar system, but instead of the output going into the pwm controllers they would go into a transmitter, across to the car or whatever and that would drive a wheel or something. I've nearly got the primary schematics done, i'll post them so you guys can have a look and see if there is anything wrong.
