GPIO buttons: AttributeError: 'int' object has no attribute 'var1'

Question

I'm trying to write code for a raspberry pi. The code is supposed to set up a connection to obd on my car. What the code is supposed to do is wait for me to press a GPIO pin and the recording will stop. This pin (27) acts as a toggle, so I can start / stop by pressing it.

I wrote the code originally outside a class just to get it to work, but I rewrote it from scratch to adapt it into a class, but the GPIO events are not behaving.

Here is the code:

import RPi.GPIO as GPIO
import time
import obd
import numpy as np


class obdScan:
     rec_loop = 0
     key_listen = 1
     rec_freq = 2 # per second
     my_data = []
     def __init__(self):
         try:
            self.conn = obd.OBD()
         except:
             print("connection failed")

    def stop_loop(self):
        self.rec_loop = (self.rec_loop +1)%2

    def closeall(self):
        self.rec_loop, self.key_listen = 0,0

    def measurement(self,val):
        device = obd.commands[1][val]
        value = self.conn.query(device).value.magnitude
        return value

    def record(self,devices):
        value=[]
        for i in range(len(devices)):
            value.append(self.measurement(devices[i]))
        self.my_data.append(value)
        time.sleep(1/self.rec_freq)
        print(["recording:", self.my_data[-1]])


if __name__ == "__main__":
    dat_file = "data.csv"
    GPIO.setmode(GPIO.BCM)

    GPIO.setup(27, GPIO.IN, pull_up_down=GPIO.PUD_UP)
    GPIO.setup(22, GPIO.IN, pull_up_down=GPIO.PUD_UP)

    try:
        my_data = np.genfromtxt(dat_file, delimiter=',')
    except:
        my_data = [[], []]
    obd_connection = obdScan()

    GPIO.add_event_detect(27, GPIO.FALLING, callback=obd_connection.stop_loop)
    GPIO.add_event_detect(22, GPIO.FALLING, callback=obd_connection.closeall)

    print("ready")
    while obd_connection.key_listen:
        while obd_connection.rec_loop:
            obd_connection.record([13,7])
    else:
        print("done")
        try:
            data = np.append(my_data,obd_connection.my_data,axis=0)
        except:
            data = obd_connection.my_data
        np.savetxt(dat_file, data, delimiter=",")

The Error I'm getting:

"TypeError: stop_loop() takes 1 positional argument but 2 were given"

Note: while pasting the code, some indentation got messed up, so assume correct indentation — Daniel M, Jun 19 '17 at 02:58

score 0 · Answer 1 · answered Jun 19 '17 at 03:13

GPIO.add_event_detect() apparently calls the passed callback with an argument containing the channel, and since you're setting your class methods as callbacks you'll need to add an additional argument in their definition:

def stop_loop(self, channel):
    self.rec_loop = (self.rec_loop + 1) % 2

def closeall(self, channel):
    self.rec_loop, self.key_listen = 0, 0

You can make it optional, tho...

GPIO buttons: AttributeError: 'int' object has no attribute 'var1'

1 Answers1