rc car

invad8er

hello,

i need to ask for some help with a project
I was needing to use a computer to control an rc car.

so far i have the wiring working.
I just don't know how to program it

Franklin

I guess your first task is to figure out what you want it to do then break that down into steps and figure out what the computer needs to do to accomplish that.

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- Stephen

invad8er

well i was going to just need basic rc functions
but using the debug terminal as the input

SRLM

Take a look at the code I posted here for ideas. It controls a BOE-BOT, but, if you take out the RF link stuff, then the code does essentially what you want.

Invent-O-Doc

If you need a place to start, get this book (there are two volumes, you want the first):

The Microcontroller Application Cookbook (Microcontroller Application Cookbooks) (Paperback)
by Matt Gilliland (Author)

Its a great book that breaks down input/output/control very and makes it very easy because the code examples are very brief. Even better for you, they are written in PBASIC which is your stamp's language. Of special interest to you should be the details on circuit protection.

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---

Thomas Talbot, MD
Gunpowder, MD, USA

invad8er

the books $30.00

I tried a code (but did not work) the debug would only accept 02

' {$STAMP BS2}
' {$PBASIC 2.5}
direction VAR Word

DEBUG "enter direction ",CR
DEBUGIN DEC direction
DO
IF (direction = 02) THEN
HIGH 0
HIGH 2
IF (direction = 01) THEN
HIGH 0
HIGH 3
IF (direction = 00) THEN
LOW 0
IF (direction = 1) THEN
HIGH 1
IF (direction = 0) THEN
HIGH 0
IF (direction = 11) THEN
HIGH 1
HIGH 2
IF (direction = 12) THEN
HIGH 1
HIGH 3
PAUSE 1000


ENDIF
ENDIF
ENDIF
ENDIF
ENDIF
ENDIF
ENDIF


END
LOOP

sylvie369

You'll want to use the SELECT...CASE structure instead of all of those nested IF-THENs. It'll clean things up considerably.
Take a look in the Basic Stamp Manual online.

invad8er

well i could not get select-case structure to work but i did get elseif to work
(program still has the problems)
' {$STAMP BS2}
' {$PBASIC 2.5}
direction VAR Word


DO
DEBUG "enter direction ",CR
DEBUGIN DEC direction


IF (direction = 02) THEN
HIGH 0
HIGH 2
ELSEIF ( direction = 03) THEN
HIGH 0
HIGH 3
ELSEIF (direction = 00) THEN
LOW 0
ELSEIF (direction = 1) THEN
HIGH 1
ELSEIF (direction = 0) THEN
HIGH 0
ELSEIF (direction = 11) THEN
HIGH 1
HIGH 2
ELSEIF (direction = 12) THEN
HIGH 1
HIGH 3
PAUSE 1000
DEBUGIN direction : direction =00


ENDIF


END
LOOP

Mikerocontroller

You have listed seven different evaluations for the variable "direction". Since the value 0 is the same as 00 then you are really only evaluating six. "ELSEIF (direction = 0) THEN" never gets evaluated because "ELSEIF (direction = 00) THEN" is identical logic. This IF-THEN-ELSEIF structure will find the first (and only the first) TRUE statement and execute the code block for that statement only.
The SELECT-CASE should work for you as well. A common mistake is using the "=" between CASE and the variable
you are evaluating. This is the syntax:

SELECT direction
CASE 0 THEN ' don't use equal sign
HIGH 0
CASE 1 THEN
HIGH 1
.
.
.
ENDSELECT

· Also, your program won't loop because you have an END statement within your loop structure.· Did you mean to end your IF-THEN-ELSEIF structure with this?· You should remove END.

Post Edited (Mikerocontroller) : 11/15/2008 4:00:37 AM GMT

invad8er

ok that cleaned it up alot and the rest of the the selection works
but the program only excepts one direction then has to be reset-any ideas?

' {$STAMP BS2}
' {$PBASIC 2.5}
direction VAR Word
DO
DEBUG "enter direction ",CR
DEBUGIN DEC direction
SELECT direction
CASE 0
HIGH 0
CASE 1
HIGH 1
CASE 2
HIGH 2
CASE 3
HIGH 3
CASE 4
HIGH 4
ENDSELECT
LOOP

Mikerocontroller

· Are you controlling motors or servos? Please post schematics or more detailed info.· Your code is sound but it looks like it won't suit your purpose.

Also, the pins will stay·HIGH once you set them.· If your program doesen't change their state they will stay that way.

Don't drive any kind of motor directly from the Stamp pins.

Post Edited (Mikerocontroller) : 11/17/2008 3:16:32 AM GMT

SRLM

Also note that if you are posting formatted code, it's best to use the code option in order to keep the format. It's difficult to quickly read unformatted code.

invad8er

the stamp is hooked to a RC controller

Mikerocontroller

· You really should consider getting some kind of motor controller for this project.·· Your·setup right now has pin 3 of the Stamp controlling the emitter current of all those transistors.· That will most definitely damage your microcontroller .·

invad8er

i probably should of used a better diagram

i had used relays
5v .002a