Controlling and LED on/off with one push button

compu · 2011-01-09 19:03

I want to control an LED with a push button
So that when I press the button the LED is on and when i press the button again the LED turns off
Can anyone give me the code for it please
thank you
really appreciate if you can help
I am using basic stamp 2
micro controller

Mike Green · 2011-01-09 21:01

First you go through the "What's a Microcontroller?" tutorial that you can download from Parallax here. There's a section (Chapter 2) that deals with turning an LED on and off and a section (Chapter 3) that deals with pushbuttons. I believe there's an example in Chapter 3 of exactly what you want. Have a look.

If you have the Stamp Editor, you may already have a copy of the tutorial in the Editor's help files.

Spiral_72 · 2011-01-09 21:03

One of two things come to mind:

#1 Use a toggle pushbutton instead of a momentary
IF IN0=1 then OUT1,1 'where your button is on pin0 and your LED is on pin1

#2 Use the "TOGGLE" BASIC Stamp command
IF IN0=1 THEN TOGGLE 1 'where your button is on pin0 and your LED is on pin1

In both cases you will likely need a debounce timer. The BASIC Stamp has an instruction just for this, although I've never used it; Look up the "BUTTON" command in your manual.

Good luck!

compu · 2011-01-10 14:39

Can you please tell me the exact code
with a do loop, for next , picking a variable , if its needed

My push button is connected to IN1
and my LED is connected to P15 soo
would it be like

Do
IF ? THEN
?
ELSE ?
HIGH ?
LOW ?
PAUSE
LOOP

compu · 2011-01-10 14:40

can you please tell me the exact code if possible sir
My push button is connected to IN3
and my LED is connected to P14

Do i need a "Do Loop" ???/
can yu plz tell me the exact code for it
thank you

Mike Green · 2011-01-10 15:57

Usually when people ask for "exact code", they have a project for school and are trying to avoid having to learn how to program in order to do their assignment. We won't help you there. Read the tutorial I recommended. If there is something in the tutorial that you don't understand, please ask for help understanding. If you try something in the tutorial and it doesn't work the way you think it should, explain what you've tried and we'll help you get it working, but we won't do your work for you.

Look at the Stamp Editor's help files for descriptions of each of the statements. HIGH and LOW require a pin number like "LOW 5" to make I/O pin 5 low. There's a space between the LOW and the pin number. You've noticed that you can use the value of an I/O pin as a variable like "IN7" to test the state of I/O pin 7. There's no space between the IN and the pin number in this case.

compu · 2011-01-10 17:54

I am sorry mate
I tried reading it in chapter 3 and also chapter 2
I ve tried the pull up resistor , and also toggle command but no LUCK I GUESS
and by the way FOI its not a school project/assignment
I am trying to make a remote controlled car for my 6 year old son
I ve completed everything but i want to know how to use the push button
The situation is like when i push the button the green LED should turn on and the car should start , when i press it again the LED should turn off and the car should stop
It you can please help me AT LEAST for my 6 year old kid who's birthday is just coming up
I would appreciate it Thank you

Desy2820 · 2011-01-10 19:02

Suggested code is below. I haven't tested this, so be prepared to test and adjust.
I'm hoping this code gives you a good starting point.
Good Luck!

' ================================================== =======================
'
‘ {$STAMP BS2}
‘ {$PBASIC 2.5}
'
' ================================================== =======================
'

[ Program Description ]

‘ Toggles an LED on and off with a button press. Button must be active-high.
'
'

[ I/O Definitions ]

LED PIN 14 ‘ Your LED on pin 14. Use a series resistor to limit current. Other end of LED to ground.
Btn PIN 3 ‘ Your active-high button wired per Basic Syntax manual, pg 139 or 141.

'

[ Constants ]

Tgt_State CON 1 ‘ Specifies that the button will be high when pressed

'

[ Variables ]

btnWrk VAR Byte

'

[ Initialization ]

btnWork = 0 ‘ Set variable for BUTTON command to zero
OUTPUT LED ‘Make the LED pin an output
LOW LED ‘ Turn off the LED
INPUT Btn

'

[ Program Code ]

Main:
DO
PAUSE 5
BUTTON Btn, Tgt_State, 255, 5, btnWrk, 1, Press
LOOP

Press:
TOGGLE LED ‘Turn LED on and off with button press.
RETURN

END

compu · 2011-01-10 19:14

Thank you so much mate
I tried using codes like
If .... THEN...... ELSEIF........
how can i play around with these types ? any idea
by the way
from this code
If i press the push button the LED will turn on and when i press it again it will turn of right ?

Desy2820 · 2011-01-10 20:11

Yes, the TOGGLE command will cause the LED to turn on, then off, then on (since it starts out as off). Toggle reads the current state, high or low, then changes it to the opposite. If it was low, it goes high, if high it goes low.

If the LED doesn't light at first, try reversing the leads. I've driven myself nuts forgetting that they are polarity senstitive--and wondering why I can't get it to turn on.

For IF, THEN, ELSE, I'd try the example code in the Basic Stamp Syntax and Reference book. I also can't recommend enough the "What's a MicroController" (WAM) text. It really helped me get started, now I'm so rusty I probably need to work through it again to blow out the cobwebs.

Syntax Manual (5th from the top within table): http://www.parallax.com/tabid/440/Default.aspx
WAM: http://www.parallax.com/Portals/0/Downloads/docs/prod/edu/28123-WAM-v3.0.pdf

I hope this helped.

Mike Green · 2011-01-10 21:20

The BUTTON statement as given by Desy2820 won't work because BUTTON does a GOTO to Press, not a subroutine call (GOSUB). The Stamp will probably reset when it does the RETURN since there's nothing to return to. Something like this should work:

DO
PAUSE 5
BUTTON Btn, Tgt_State, 255, 5, btnWrk, 1, Press
GOTO keepGoing
Press:
TOGGLE LED ‘Turn LED on and off with button press.
keepGoing:
LOOP

bsnut · 2011-01-10 23:38

I am in agreement with Mike Green on both of his posts. That now said, you should download the information and the help file that is with the Basic Stamp Editor program. There is example program code for every instruction/command for the Basic Stamps.

Here is some code to get you started.

Main:
If IN0 = 1 THEN Ledon  'Goto label Ledon when PIN 0 is true
GOTO Main  ' Goto label Main when PIN 0 is false

Ledon:
TOGGLE 1  'Toggle led on and off on PIN 1
GOTO Main  'Goto Main

This should give some idea what you need to do.

erco · 2011-01-11 09:44

simplifies to:

main:if in0=0 then main
toggle 1:pause 500:goto main

the pause 500 gives you 500 ms to release the pushbutton.

wespiece · 2013-05-21 12:24

along these same lines - I am building an electric car controller for lights and accessories. I have the code below to toggle lights on and off, but if wanted to make Output 0 - toggle on and off AND flash when it was On what code would I need to add. I want to create a flasher circuit basically, with a toggle input thru a PC connection. Code is below:'

{$STAMP BS2e}
' {$PBASIC 2.5}
' Hook up a two LEDs to Pins 3 and 4 to test this.
' Then VB code is set up for Com1 incase you have to change this to the Com
' port of your computer.
command VAR Byte
SI PIN 1
  Main:
  SERIN 16, 16468, [STR command\1]    ' Get 1-byte string

CheckCommand:
  IF command = "1" THEN
     GOTO Task1
  ENDIF
  IF command = "2" THEN
     GOTO Task2
  ENDIF
  IF command = "3" THEN
     GOTO Task3
  ENDIF
  IF command = "4" THEN
     GOTO Task4
  ENDIF
GOTO Main

Task1:
TOGGLE 0
GOTO Main
Task2:
LOW 0
GOTO Main
Task3:
TOGGLE 1
GOTO Main
Task4:
LOW 1
GOTO Main

Duane Degn · 2013-05-22 00:46

wespiece wrote: »

I have the code below to toggle lights on and off, but if wanted to make Output 0 - toggle on and off AND flash when it was On what code would I need to add.

I don't use the Basic Stamp much myself, but I think the following code should do what you want.

{$STAMP BS2e}' {$PBASIC 2.5}
' Hook up a two LEDs to Pins 3 and 4 to test this.
' Then VB code is set up for Com1 incase you have to change this to the Com
' port of your computer.


command VAR Byte
onFlag VAR Nib
flashPhase VAR Nib
loopCount VAR Word
FLASH_LOOPS CON 1000 ' Change this value to adjust blinking rate
SI PIN 1


Main:
  SERIN 16, 16468, [STR command\1]    ' Get 1-byte string


CheckCommand:
  IF command = "1" THEN
     GOSUB Task1
  ELSEIF command = "2" THEN
     GOSUB Task2
  ELSEIF command = "3" THEN
     GOSUB Task3
  ELSEIF command = "4" THEN
     GOSUB Task4
  ENDIF
  GOSUB CheckFlash
GOTO Main


Task1:  ' toggle blinking LED on or off
  IF onFlag = 0 THEN ' if turning on, setup flash
    onFlag = 1       ' variable used to keep track
    flashPhase = 1   ' of flash state
    loopCount = 0
  ELSE
    onFlag = 0
  ENDIF
RETURN


Task2: ' turn off blinking LED
  onFlag = 0
  LOW 0
RETURN
  
Task3:
  TOGGLE 1
RETURN
  
Task4:
  LOW 1
RETURN


CheckFlash:
  IF onFlag = 1 THEN           ' Do we need to worry about flashing?
    IF loopCount = FLASH_LOOPS ' Should LED state change yet?
      loopCount = 0            ' Reset counter.
      IF flashPhase = 1        ' Which phase were we just in?
        flashPhase = 0         ' Change phase and LED state.
        LOW 0
      ELSE
        flashPhase = 1
        HIGH 0
      ENDIF
    ELSE    
      loopCount = loopCount + 1 ' No phase change. Just add to counter.
    ENDIF
  ENDIF
RETURN

Adjust the value of "FLASH_LOOP" to change the blinking rate.

I changed many of the "GOTO" statements to "GOSUB" and added "ELSEIF" statements instead of just "IF" statements. These changes make the program call "CheckFlash" on each loop.

Let me know how/if it works.

I don't have the Basic Stamp software installed on this PC so I haven't tested it.

wespiece · 2013-08-14 07:08

getting an error on the last else statement - else must be proceeded by If or Case ELSE...
loopCount = loopCount + 1 ' No phase change. Just add to counter.
ENDIF
ENDIF
RETURN if I chop out this statement it works but the led does not flash and a 1 toggles the led - 2 turns it on and 1 turns it off again thx for the help here

Mike Green · 2013-08-14 07:33

Should be: IF loopCount = FLASH_LOOPS THEN

Similarly: IF flashPhase = 1 THEN

wespiece · 2013-08-14 07:49

modified it to look like this - but still getting the error shown aboveCheckFlash:
IF onFlag = 1 THEN
IF loopCount = FLASH_LOOPS THEN loopCount = 0
IF flashPhase = 1 THEN flashPhase = 0
LOW 0
ELSE
flashPhase = 1
HIGH 0
ENDIF
ELSE
loopCount = loopCount + 1 ' No phase change. Just add to counter.
ENDIF
ENDIF
RETURN

Mike Green · 2013-08-14 08:08

Please read the chapter on the IF statement in the Basic Stamp Syntax and Reference Manual or in the Stamp Editor's help files. The IF statement has two forms:

1) IF <expression> THEN <statement>

2) IF <expression> THEN
      <statement>
   ELSE
      <statement>
   ENDIF

You can't combine the two forms, so "loopCount = 0" has to be on a separate line. Similarly "flashPhase = 0" has to be on a separate line.

Duane Degn · 2013-08-14 10:36

wespiece wrote: »

still getting the error shown aboveCheckFlash:

wespiece,

Sorry about having so many errors in the program I posted. I don't use Basic Stamps much and I didn't even have the editor installed on my computer at the time or I would have at least checked the code to see if it compiled.

IIRC, I was trying to illustrate how you'll need to monitor the state of the LED over multiple loops.

It looks like Mike Green has you pointed in the right direction on how to fix the syntax.

gbell · 2016-07-30 17:57

compu wrote: »

I want to control an LED with a push button
So that when I press the button the LED is on and when i press the button again the LED turns off
Can anyone give me the code for it please
thank you
really appreciate if you can help
I am using basic stamp 2
micro controller

Well, here's your code:

' {$STAMP BS2}
' {$PBASIC 2.5}
Btn PIN 0
BTNwrk1 VAR Byte

START:

brite:
DO
HIGH 15
HIGH 14
HIGH 13
BUTTON btn, 0, 255, 20, BTNwrk1, 1, offf
LOOP
offf:
DO
LOW 15
LOW 14
LOW 13
BUTTON Btn, 0, 255, 20, BTNwrk1, 1, brite
LOOP

erco · 2016-07-31 14:23

Or else, use nothing but an on/off pushbutton switch and save your $50 BS2 for a more interesting project.

Publison · 2016-07-31 14:37

gbell wrote: »

compu wrote: »

I want to control an LED with a push button
So that when I press the button the LED is on and when i press the button again the LED turns off
Can anyone give me the code for it please
thank you
really appreciate if you can help
I am using basic stamp 2
micro controller

Well, here's your code:

' {$STAMP BS2}
' {$PBASIC 2.5}
Btn PIN 0
BTNwrk1 VAR Byte

START:

brite:
DO
HIGH 15
HIGH 14
HIGH 13
BUTTON btn, 0, 255, 20, BTNwrk1, 1, offf
LOOP
offf:
DO
LOW 15
LOW 14
LOW 13
BUTTON Btn, 0, 255, 20, BTNwrk1, 1, brite
LOOP

Welcome to the forums!

The original Poster has not been around since 2011, so I do not think he will be seeing your post, but thanks for posting!

Controlling and LED on/off with one push button

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