Computer Controlled RC Car
August 2003

Update August 2012:
See the Programmable RC Car article for an updated version of this project.
This project article was originally written in 2003 when most computers had parallel ports. This is no longer the case, so much of this information is now outdated.

Introduction

I started getting interested in parallel port interfacing Dec. of 2001. I was taking a high school "Computer Engineering" course and as a bonus the teacher Mr. Damian said we should research how to control an 8 segment display through the computer. I researched and started out in QBasic. It was very neat when I was able to switch an LED on and off via the computer. I then built a circuit using 8 NOT gates and and a number display. From then on I've been quite interested in parallel port interfacing. Later that year I bought an LCD Screen and interfaced it to the parallel port.

I thought up the idea that it would be really cool to control a remote control car controlled by the parallel port. I did some research and Mike Beauchamp did just that and to top it off it's controllable over the internet (atleast it used to be). For Christmas I requested one of those Mini RC cars and off I went.

Want to build your own? How-To Guide now avaliable in the Articles Section.

Hardware

The first thing I did open up the remote. 3 screws - no problem. The PCB (middle pic) is exposed and you can clearly see the 2 LEDs and the 4 buttons. There is a screw on the PCB that you can take out and expose the solder side (right pic). I then soldered 1wire to each of the 4 buttons and 1 wire to the common ground. The wires are connected to a connector (see pic below) that I cut off of an old serial port connector.

Up-close solder connections. Gotta
love the shrink tube.

Finished Remote. Aint it pretty?

The remote closes up nicely with the connector exposed (above, right of the remote). I wanted to do this project without wrecking the remote so that it can be driven without the PC if wanted. The next step involves the contruction of the cable to interface the remote to the PC.

This is the cable I built to interface the remote to the PC's parallel port. I used a standard parallel port connector ($1.00 @ KWSurplus), 4 2N3904 transistors, solder board and floppy drive cable. I'm not very proud of my solder job (right pic). It's extremely messy, but functional. The middle pin of each transistor is connected to 1 pin of the parallel port. One pin on each transistor is connected to both the ground of the computer and the ground of the remote, making a common ground. The last transistor pin is conncted to a pin that connects to the remote (left pic). The pins in the left pic connect to the remote adapter connection. When a PC parallel port pin is turn high (+5V) it completes a circuit between a remote button and the common ground, simulating a button press. In this way, the car's movement can be precisely controlled via PC software (see below).

Software

As I was building it, I was testing functionality with QBasic because of it's easy to use parallel port control. After I knew everything was working, I wrote a fairly simple program (just the main screen) and then modified it considerably for my Gr 11 computer science final project.

Main Screen:
The car can be manually driven via arrow keys or A-W-S-D. The arrow directions turn blue when the corresponding key is pressed.

Config / Extras Screen:
This is the bulk of the program. You can temporarily change the port that the program outputs to, have the car be controlled via random motion, write a sequence of movements (in a txt file) and have the car follow them or have the car runs one of the 4 predifined sequences. Options are setup in config.txt included in the zip file. Extensive documentation on the software can be found here and you can download (and hopefully use) this software here.

Source code for a similar, but simpler example program can be found here (also written in VB6).

Pics

Fits Nicely Together

Project Cost

Item:	Cost:
Mini RC Car	23.00
Solder Board	0.50
Transistors	1.50
Wires, cables, connectors	3.00
Total:	$28

Comments

I REQUEST YOU to send the software that can control any rc car to my Email id

Posted by sanjay on 2013-03-25 @ 08:57

can u do it with a parrallel port to usb cable

and how do u know a parrallel port address

and what if u dont have a parrallel port in a i7 laptop

Posted by shewveem on 2013-02-28 @ 05:44

@hey
There is no PIC used in this project.

Posted by Jon on 2013-02-25 @ 14:04

Hi Can i use PIC18 instead of PIC16?

Posted by hey on 2013-02-25 @ 11:28

This is a very cool & intresting thing.Very very thanks for publishing a nice experiment

Posted by avinash on 2013-01-31 @ 06:27

Posted by gokulan on 2013-01-12 @ 05:50

hey, that's a good articles....
can u send me your completed information???
plz send me it...

this is a my email gihanlakshan@ymail.com

Posted by Gihan on 2012-11-23 @ 01:50

hi ...i am doing my project please can you give us your completed information about your projectss
i would happy if you help us sir t my project

this is my emial chuajohnhensen@yahoo.com

Posted by john hensen chua on 2012-10-12 @ 19:26

@Angel
See the link at the bottom of the software section of this page.

Posted by Jon on 2012-10-9 @ 09:11

Can you please email me a Source code for this project??

Posted by Angel on 2012-10-9 @ 04:32

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