Coin Counter in Raspberry Pi

Question

I'm having a problem to count coins in raspberry usin RPi-GPIO.

This is the code:

 import RPi.GPIO as GPIO

 GPIO.setmode(GPIO.BCM)
 GPIO.setup(23, GPIO.IN)

 while True:
    print(GPIO.input(23))

I called the manufacturer and he said the Coin Counter sends a pulse with value 1 constantly and the value 0 when the coin down. But in the console is showing 0 and 1 at random. And nothing change when coin dropped.

4 wire outputs: black and red are 12v (font), white is pulse on 23 pin (1 constantly, 0 when drop the coin) and purple is to count coins on separeted led. Font 12v, and pulse (white wire) is 0.19~0.25 volts, and I used 10k resistor in this wire. And I use Raspberry pi B+.

Obs: Pulse is digital.

I have this Coin Counter:

Answer 1

From the description it seems likely that the white pulse wire is an open collector output. In other words it floats to an external voltage and is pulled down to zero at each pulse.

Instead of

GPIO.setup(23, GPIO.IN)

use

GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD_UP)

GPIO 23 will then normally read 1 but will read 0 at each pulse.