Reg: Python programming

[vishnuvkv]

Hi,
I have to connect 4 servomotors, 2,12v DC motors ,LCD display and 4 sensors to raspberry. Is it possible to program everything in a single python file. Can anyone suggest a good method to get this done?

[joan]

Of course it is possible.

Start off getting one device to work and then add more.

http://elinux.org/RPi_GPIO_Code_Samples#Python

[vishnuvkv]

I tried, but I am facing some time delay issues as I have to use "time.sleep()" function in the program multiple times.

[MarkHaysHarris777]

Is it possible to program everything in a single python file.

Of course its possible ...

... but you probably don't want to do that. Joan's advice is sound; do that, but also think about this: you may want to control various devices in similar ways using similar naming conventions. If you place the device control header information (function definitions, globals, dictionaries, &c) in separate files then you can have your devices in different 'namespaces' in Python. Examples:

import RPi.GPIO as GPIO

GPIO becomes a namespace. Names within this space can be the SAME as names in other spaces because we're going to qualify with GPIO... GPIO.setup()

import motor_driver as MOTOR

import relay_driver as RELAY1

... you get the idea. Each of those namespaces should be in a separate file:

motor_driver.py

relay_driver.py

&c

You are free to stuff everything in ONE file... but its bad form, and it will cause you difficulties galore as your project becomes non trivial.

marcus

[vishnuvkv]

Thank you guys

[vishnuvkv]

Hi..
I am using Raspberry pi 2 B+. I need to run a servomotor and a 12Vdc motor at a time and I also need to control the speed of the dc motor so i am using a driver circuit. So both servo and dc motor is using PWM. Is there any problem in running two PWM signals at a time?Because, when I tried to run the motor was not working properly.

[joan]

There is no problem in providing multiple PWM from the Pi.

[vishnuvkv]

Hi...I wrote a number to a text file using the command " f.write(str(number))" and I need to read this number in other .py file and compare that value. How can I do this?? Please help...

[B.Goode]

https://docs.python.org/3/tutorial/inpu ... ting-files

[vishnuvkv]

I am a beginer in RPi ,my program is slowing down while using threading. How can this be rectified?
Please help

[vishnuvkv]

Code: Select all

import RPi.GPIO as GPIO
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(13,GPIO.OUT)
p1=GPIO.PWM(13,50)#base
GPIO.setup(26,GPIO.OUT)
p2=GPIO.PWM(26,50)#side
GPIO.setup(19,GPIO.OUT)
p3=GPIO.PWM(19,50)#top
GPIO.setup(2,GPIO.IN,pull_up_down=GPIO.PUD_UP)#start/stop
GPIO.setup(3,GPIO.IN,pull_up_down=GPIO.PUD_UP)#fault


GPIO.setup(5,GPIO.IN)
scrap_count =0

while True:
   
         a=GPIO.input(2)
         a1=GPIO.input(3)
         a2=GPIO.input(5)
      
       # print a,a1
         if (a==0 and a1==1 and a2==1): 
            
              time.sleep(10)
              p3.start(7)
              time.sleep(1)
              p2.start(10.5)
              time.sleep(1)
              p3.ChangeDutyCycle(10)
              time.sleep(1)
              p2.ChangeDutyCycle(12)
              time.sleep(1)
              p1.start(6)
              time.sleep(1)
              p2.ChangeDutyCycle(10.5)
              time.sleep(1)
              p3.ChangeDutyCycle(7)
              time.sleep(1)
              p2.ChangeDutyCycle(12)
              time.sleep(1)
              p1.ChangeDutyCycle(10)
              time.sleep(1)
              scrap_count=scrap_count+1
              print "Scrap Count = ",scrap_count
              k=open('/home/pi/Hari/text_output_files/arm.txt','w')
              k.write("Scrap Count = "+ str(scrap_count))
          
        else:
           
               p1.stop()
               p2.stop()
               p3.stop()
            
        elif a==1:
           
              scrap_count=0
              k=open('/home/pi/Hari/text_output_files/arm.txt','w')
              k.truncate()
           

As a part of my project , I have writting the above code for a robotic arm with 3 servo motors. Here when the process is stopped and started agian arm is not working properly. How this code can be modified? Please help...I am stucked here.

[B.Goode]

Please edit your post to include your script within [ CODE ] markers, using the 'button' at the top of the message edit screen.

Without indentation your While and If blocks are meaningless.

[vishnuvkv]

I have edited the post .Please check the code.

[B.Goode]

I have edited the post .Please check

You can, and should, preview your own post before submitting it. It looks unchanged to me.

[vishnuvkv]

I have edited the post .Please check

You can, and should, preview your own post before submitting it. It looks unchanged to me.

Sir,
How to use that

Code: Select all

 makers. I am using this for the 1st time that is why I am asking.

[bensimmo]

faq.php?mode=bbcode

[vishnuvkv]

Hi,
I am using a motor driver and 20*4 lcd display. When the motor is started lcd is displaying wrong characters. What may be the reason? please help

[vishnuvkv]

I have edited the post .Please check

You can, and should, preview your own post before submitting it. It looks unchanged to me.

Sir,
I have edited the code please check.
Thank you

[B.Goode]

Hi,
I am using a motor driver and 20*4 lcd display. When the motor is started lcd is displaying wrong characters. What may be the reason? please help

The code you have posted does not appear to make any use of an LCD display so this will be impossible to diagnose.

[vishnuvkv]

Hi,
I am using a motor driver and 20*4 lcd display. When the motor is started lcd is displaying wrong characters. What may be the reason? please help

The code you have posted does not appear to make any use of an LCD display so this will be impossible to diagnose.

Sir,
The code which I have posted is for robotic arm with 3 servo motors. Can u please check on that also? And what may be the reason for printing unwanted characters in LCD display when motor is started? Do I have to post the code?

Thank you

[vishnuvkv]

Hi,

I will be running two python files in background using "&" operator but I am not able to stop them .Please help.

Thankyou

[bensimmo]

Hi,

I will be running two python files in background using "&" operator but I am not able to stop them .Please help.

Thankyou

Killall python
Should stop all python programmes

Quick search on that and this gives more info
http://www.linfo.org/killall.html

[vishnuvkv]

Thank you.

[vishnuvkv]

[/quote]

Killall python
Should stop all python programmes

Quick search on that and this gives more info
http://www.linfo.org/killall.html[/quote]

Thank you.

[vishnuvkv]

Hi,

Do we have to update date and time every time when raspberry is turned on , if we are not using internet connection?

Thankyou