[Solved] GPIO - Python

[bakouz]

Hi everyone, i come here because i have a problem with raspberry GPIO, and i don't understand what i suppose to do.

I explain.

I bought a button like this:

And cable to connect to GPIO.

One go to GND and the other on a pin (i know the forbidden pin, i guess).

I have a python script to show me if i push-on it is 1 or it is 0. With this one:

Code: Select all

#!/usr/bin/env python
# -*- coding: latin-1 -*-

import RPi.GPIO as GPIO, time
import time

GPIO.setmode(GPIO.BCM)
BUTTON1 = 2

GPIO.setup(BUTTON1, GPIO.IN)

while True:
	print GPIO.input( BUTTON1 ) 

If i connect my button on the pin 2 (BCM), it is work.
Like with the button 3.

But with any other: Like GPIO 10 or 9 or any others
I push-on -> 1 -> Ok working.
I push-off -> 10 00 11 01010101. no working. It make anything, he changes alone -> 00 100001111010111111000.

I don't know why.
I ask me, if i connect to the good pin ?

Could you help me plz ?

Thank a lot.


PS. I have a raspberry PI B and i use this schema to help me with pins.



Best Regards.

[elParaguayo]

Do some searching on the forum for debouncing. I suspect the problem is your input is floating and needs to be pulled high or low. It's a common problem so I'm sure you'll find the information you need.

[AndrewS]

http://raspi.tv/2013/rpi-gpio-basics-6- ... pull-downs should point you in the right direction

[bakouz]

Thanks elParaguayo for your quick answer, that you said comforts me, I believed my raspberry was out ^^.

Thanks AndrewS, i will read your page tonight after my work day.

I will come back here for i say you what happen.

Thanks again.

[Mosco]

Hello there


Have a look at this picture....its been a while since I used the GPIOS but there are some pins which have default uses but can be used as GPIOs and for that they need to be chenged from the default functions. Unfortunately I cannot remember whether I dd this using python or something else so just look it up....The pins which are not working are probably the pins that have have default uses so just find out how to change them otherwise you only have 8 "free" GPIOs to use.

look closely at this image and you will see some pins are shows as "GPIO" but still have other labels like SPI and I2C etc...

Hope that helps...

here is the link to the image
http://www.google.co.za/imgres?imgurl=h ... =0&ndsp=19

[bakouz]

Hello there


Have a look at this picture....its been a while since I used the GPIOS but there are some pins which have default uses but can be used as GPIOs and for that they need to be chenged from the default functions. Unfortunately I cannot remember whether I dd this using python or something else so just look it up....The pins which are not working are probably the pins that have have default uses so just find out how to change them otherwise you only have 8 "free" GPIOs to use.

look closely at this image and you will see some pins are shows as "GPIO" but still have other labels like SPI and I2C etc...

Hope that helps...

here is the link to the image
http://www.google.co.za/imgres?imgurl=h ... =0&ndsp=19

Hello,
Thanks for your answer, so if understand what you said, the GPIO 4 should be work ? ( i looked your image, thank for that.)
I tried, and it doesnt' work, it do 00111001

i will try with the Adrew's link. and i will see

If you remember where you saw this, it's could be great



EDIT:
Hi guys i read your links and i understand the problem, but i tried this code

Code: Select all

import RPi.GPIO as GPIO  
from time import sleep     # this lets us have a time delay (see line 12)  
GPIO.setmode(GPIO.BCM)     # set up BCM GPIO numbering  
GPIO.setup(4, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)      


try:  
	while True:            # this will carry on until you hit CTRL+C  
		if GPIO.input(4): # if port 4 == 1  
			print "Port 4 is 1/HIGH/True - LED ON"  
			print GPIO.input( 4 ) 
			
		else:  
			print "Port 4 is 0/LOW/False - LED OFF"  
			print GPIO.input( 4 )
			
		sleep(0.1)         # wait 0.1 seconds  
  
finally:                   # this block will run no matter how the try block exits  
	GPIO.cleanup()         # clean up after yourself  

And it doesn't work :/

Any idea?

[mrteach]

are you getting any specific errors?

maybe try debugging?

change whats under while True to this

Code: Select all

while True:
    print  GPIO.input(4)
    sleep(0.2)

you can lower the sleep if you want to 0.1. but just click the button and see if the numbers change. if they don't then you probably put it on the wrong pin or connected it wrong.

[bakouz]

are you getting any specific errors?

maybe try debugging?

change whats under while True to this

Code: Select all

while True:
    print  GPIO.input(4)
    sleep(0.2)

you can lower the sleep if you want to 0.1. but just click the button and see if the numbers change. if they don't then you probably put it on the wrong pin or connected it wrong.

Hi Mrteach,

I have not error with the last script i posted.
Just the same result.

And if you look my first post, we can see almost the same script as you, i have not error on python script.
Just the result of the print which is 011010101 when i pull-up and 0 continue when i pull-down.

I guess i should to disable UART and other pins like this.

Thanks for your help.

[joan]

I've lost track of if you have a problem or not.

Please note that gpios 0, 1, 2, and 3 (I2C) have hard-wired pull-up resistors to 3.3V. The internal pull-up/down resistors will have no effect.

[rpdom]

I think you said you're wiring the button between GPIO and GND.

For that you need Pull-Up resistors, not Pull-Down, so you would use

Code: Select all

GPIO.setup(4, GPIO.IN, pull_up_down=GPIO.PUD_UP)

As joan said, the two pins that work have permanent Pull-Up resistors on the board. The others don't.

[bakouz]

I think you said you're wiring the button between GPIO and GND.

For that you need Pull-Up resistors, not Pull-Down, so you would use

Code: Select all

GPIO.setup(4, GPIO.IN, pull_up_down=GPIO.PUD_UP)

As joan said, the two pins that work have permanent Pull-Up resistors on the board. The others don't.

Ohhh okeyy.
I think you are right !
I try tonight ! Thanks a lot !

And sorry joan if you dit not understand my explications ! It is a little bit difficul to explain in english^^
To summarize the python script does not give me an error like "Erro line 20":
And i know the script does not work because i have not the result i shoud to have ^^.

But i just understand the pull-down and up resistors so i think tonight it will be working !

[bakouz]

Yeaaaaah it is working !


Thank a lot all of you !
I just change :

Code: Select all

GPIO.setup(10, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

by

Code: Select all

GPIO.setup(10, GPIO.IN, pull_up_down=GPIO.PUD_UP)

Thank again

[elParaguayo]

Congratulations - have fun with your project.