View Full Version : PC controls: Control Bit from your Computer

12-21-2002, 04:40 AM
click here (http://forums.off-topic.net/showthread.php?s=&threadid=512781)

12-23-2002, 01:41 AM
you have to be logged into the first forum.. i don't know about 3geez. i'm a member there, so the link loads for me.. i'll copy/paste

Friend of mine and I decided to take apart one of those micro R/C controllers to see what made em work. Thye're ungodly simple, and we started thinking of ideas to control it via PC. We used el-cheapo Ratshack PNP transistors to trigger the buttons when the PC's parallel port data pins send a 0 to the corresponding port for forward, back, left and right.

We've written simple code to control the car and added in some automated functions... like three point turns with a single keystroke.

All in all a fun lil project

On with pics!

This is the ripped apart controller, modified and wired to the parallel port.

The car being subjected to this torture

Closeup of the controller.

Pic of laptop, with code.

Happy hacking!

he's still workin on it, but when he finishes, i'll be sure to post the new info.

12-23-2002, 02:04 AM
interesting i guess if you were extreamly bored
or just wanted to be the first

12-23-2002, 05:43 AM
i seriously dont see the point of that

12-26-2002, 05:18 AM
you could hold remote races via webcam.. and take credit card payments to enter, they choose a car.. and win money if they win.. would be DAMN sweet.

12-26-2002, 08:55 PM
LOL, is that Qbasic or Turbo Pascal that I see running on that pc? Old skool!

12-27-2002, 02:14 AM
i think.. that it's Qbasic but not sure

12-27-2002, 04:52 PM
Off you go...

Also updated the thread title for clarity.

12-28-2002, 01:28 PM
Sabz5150, that's brilliant! Welcome to TinyRC.com and we can't wait to see your next project! :D

04-16-2003, 01:36 AM
Originally posted by Sabz5150
Wow, didn't think anyone would be this interested in my lil hackjob :)

Making it work is easy, but needs a little bit of electronic knowledge. The buttons on the transmitters are simple pushbutton switches, so all you need to do is replace them with something that can be digitally switched... transistors. Replace the switches with transistors, with the collector and emitter pins in the place of the switch's pins. Now, you can either touch the base pin to ground or positive and trigger the controller.

Depending on how your transmitter is wired, you'll need to use either PNP or NPN transistors. This is where the electronics knowledge kicks in. If you're unsure which you need, test. Wire one up temporarily and trigger it. Touch the base of a PNP to the negative side of your batteries, and vice versa for NPN. If it's the wrong one, it will get very hot very fast. Use the other type.

You'll use the same type of transistor for all 4 buttons, so the hard part is done.

Data port time :) Your best bet is to buy a male DB-25 port from Fry's or RatShack. Connect each base pin of the transistors to a data pin on the DB-25 port. Pins 2, 3, 4 and 5 are what I used. After that, connect a ground pin (Pin 18) to the negative side of your batteries.

That's it for the controller mod :) We're still working on software, so that is still a little ways away from being complete. If you can hammer out some code, then you should be able to write a program to control it. Just send high or low signals to the parallel port on pins 2, 3, 4 and 5 to control the car's movements. Depending on the type of transistors you used, either the high signal or low signal will trigger the controller.

Sorry about the quick bang-up howto. I'm working on one with pics and diagrams, so stay tuned :)

Our next project is coming along well. We took a mouse apart, and used the rotating axles and sensors to count rotation over time... and will hopefully be able to plot it on a graph. Yup, a micro sized desktop dyno :D

do i see duct tape in the future hehe:D and will it work on overlands and racers