Led issue with arduino controled by raspberry pi/python

Question

I'm having an issue with 2 parts of my project. I am using a raspberry pi to read and control a potentiometer and some leds.

1 when I'm controlling leds with a potentiometer my leds flash on my low threshold but not on my higher, how can I fix this?

(Fixed)2 my potentiometer has to be set at 0 when first starting the script other wise I get abnormal reads from my potentiometer, how can I fix that?

I have tried adding a delay before and after. I've tried adding the center string before and no luck. I've searched for solutions all over Google with no luck. All I have found is script for the blink example.

I have this script run on my raspberry pi through python to control my arduino. If I have it posted in the wrong area please let me know where it should be posted so I can move it.

Here is my script!

from nanpy import Arduino
from nanpy import serial_manager
from time import sleep

serial_manager.connect('/dev/ttyUSB0')

POT = 0
LED1 = 13
LED2 = 12
LED3 = 11
LED4 = 10
LED5 = 9
LED6 = 8
LED7 = 7
LED8 = 6

Arduino.pinMode(POT, Arduino.INPUT)
Arduino.pinMode(13, Arduino.OUTPUT)
Arduino.pinMode(12, Arduino.OUTPUT)
Arduino.pinMode(11, Arduino.OUTPUT)
Arduino.pinMode(10, Arduino.OUTPUT)
Arduino.pinMode(9, Arduino.OUTPUT)
Arduino.pinMode(8, Arduino.OUTPUT)
Arduino.pinMode(7, Arduino.OUTPUT)
Arduino.pinMode(6, Arduino.OUTPUT)

print "starting"
while True:
    pot = Arduino.analogRead(POT)
#this is the section that is blinking when it shouldn't
    if pot < 450:
        Arduino.digitalWrite(LED1, Arduino.HIGH)
        Arduino.digitalWrite(LED2, Arduino.HIGH)
        Arduino.digitalWrite(LED3, Arduino.HIGH)
        Arduino.digitalWrite(LED4, Arduino.HIGH)
        Arduino.digitalWrite(LED5, Arduino.LOW)
        Arduino.digitalWrite(LED6, Arduino.LOW)
        Arduino.digitalWrite(LED7, Arduino.LOW)
        Arduino.digitalWrite(LED8, Arduino.LOW)
        sleep(.5)
#
    if pot < 650 > 450:
        Arduino.digitalWrite(LED1, Arduino.LOW)
        Arduino.digitalWrite(LED2, Arduino.LOW)
        Arduino.digitalWrite(LED3, Arduino.LOW)
        Arduino.digitalWrite(LED4, Arduino.LOW)
        Arduino.digitalWrite(LED5, Arduino.LOW)
        Arduino.digitalWrite(LED6, Arduino.LOW)
        Arduino.digitalWrite(LED7, Arduino.LOW)
        Arduino.digitalWrite(LED8, Arduino.LOW)
        sleep(.1)
    if pot > 650:
        Arduino.digitalWrite(LED1, Arduino.LOW)
        Arduino.digitalWrite(LED2, Arduino.LOW)
        Arduino.digitalWrite(LED3, Arduino.LOW)
        Arduino.digitalWrite(LED4, Arduino.LOW)
        Arduino.digitalWrite(LED5, Arduino.HIGH)
        Arduino.digitalWrite(LED6, Arduino.HIGH)
        Arduino.digitalWrite(LED7, Arduino.HIGH)
        Arduino.digitalWrite(LED8, Arduino.HIGH)
        sleep(.5)
#    print pot

Answer 1

I see a problem at initialization, in this line:

POT = Arduino.analogRead(0)

Then, in the while, you use POT as a pin number here, but POT will be initialized in the line above as a variable:

pot = Arduino.analogRead(POT)

I think that's why you get unexpected behaviour. I think that if you change the initialization of POT to POT=0 or the pin number that your pot is connected to (if it is not pin 0), it might work.

Answer 2

I figured it out. The blink issue was not expected. However it was acting like the leds were set to an off delay for about .5 seconds. Here is my new script.

from nanpy import Arduino
from nanpy import serial_manager
from time import sleep

serial_manager.connect('/dev/ttyUSB0')

POT = 0
LED1 = 13
LED2 = 12
LED3 = 11
LED4 = 10
LED5 = 9
LED6 = 8
LED7 = 7
LED8 = 6

Arduino.pinMode(POT, Arduino.INPUT)
Arduino.pinMode(13, Arduino.OUTPUT)
Arduino.pinMode(12, Arduino.OUTPUT)
Arduino.pinMode(11, Arduino.OUTPUT)
Arduino.pinMode(10, Arduino.OUTPUT)
Arduino.pinMode(9, Arduino.OUTPUT)
Arduino.pinMode(8, Arduino.OUTPUT)
Arduino.pinMode(7, Arduino.OUTPUT)
Arduino.pinMode(6, Arduino.OUTPUT)

print "starting"
while True:
    pot = Arduino.analogRead(POT)
    if pot < 450:
        Arduino.digitalWrite(LED1, Arduino.HIGH)
        Arduino.digitalWrite(LED2, Arduino.HIGH)
        Arduino.digitalWrite(LED3, Arduino.HIGH)
        Arduino.digitalWrite(LED4, Arduino.HIGH)
        Arduino.digitalWrite(LED5, Arduino.LOW)
        Arduino.digitalWrite(LED6, Arduino.LOW)
        Arduino.digitalWrite(LED7, Arduino.LOW)
        Arduino.digitalWrite(LED8, Arduino.LOW)
        sleep(.01)
    elif pot > 650:
        Arduino.digitalWrite(LED1, Arduino.LOW)
        Arduino.digitalWrite(LED2, Arduino.LOW)
        Arduino.digitalWrite(LED3, Arduino.LOW)
        Arduino.digitalWrite(LED4, Arduino.LOW)
        Arduino.digitalWrite(LED5, Arduino.HIGH)
        Arduino.digitalWrite(LED6, Arduino.HIGH)
        Arduino.digitalWrite(LED7, Arduino.HIGH)
        Arduino.digitalWrite(LED8, Arduino.HIGH)
        sleep(.01)
    else:
        Arduino.digitalWrite(LED1, Arduino.LOW)
        Arduino.digitalWrite(LED2, Arduino.LOW)
        Arduino.digitalWrite(LED3, Arduino.LOW)
        Arduino.digitalWrite(LED4, Arduino.LOW)
        Arduino.digitalWrite(LED5, Arduino.LOW)
        Arduino.digitalWrite(LED6, Arduino.LOW)
        Arduino.digitalWrite(LED7, Arduino.LOW)
        Arduino.digitalWrite(LED8, Arduino.LOW)
        sleep(.01)
    print pot