User:Wordfa/oldphonehack

Phone Hacking Project

This is a project for SS25 to create a story gathering system using an old phone. What do we want the telephone to do? Fred wants to make it into an API that we can use it later on with the data.

T65 Rotary Phone bought by Sevgi n' Fred

Parts Required

USB interface to 3.5mm

https://www.adafruit.com/product/1475

3.5mm Cables

Old phone (T65)

https://www.marktplaats.nl/v/telecommunicatie/vaste-telefoons-niet-draadloos/m2158407457-ptt-t65-goed-werkende-nostalgische-telefoon

Raspberry Pi

TRS 3.5 Jack x2

Loads of wires

old headphones with a mic (apple earpod works best)

Things we done

[11 (Neg), 12(Pos) speaker output]

- We took the phone apart and got the speaker to work by connecting the blue and red cables from the phone out to the audio jack to the soundcard to the computer. played show me the body, was good.

- Then we tried the microphone but its a carbon mic and it didnt work. so we atttached a battery and hoped. didnt work.

- We took apart wired headphones that had mic in them to see if we could use the mic from it rather than the carbon mic in the telephone.-> didnt work, headphone cable is TRRS not TRS:

spent a day trying to wire up TRRS to an audio cable, turns out the audio jack was the wrong kind.

then wired it directly to a TRS jack, worked!!!!!!!!!!!!!

then cable managed, looks beautiful now. now we have working speakers and working mic.

This is how you could make it work too:

From the headphones you need to...

Connect th Blue (Ground) to the Sleeve of the TRS jack

Connect the Red (mic) to Pin (Ring) 1 or 2 of the TRS jack

MAKE SURE THE HEADPHONES CONNECTION IS CLOSED!

The wiring used

sketch of the wiring of the handset connection

Next Steps:

Work out how to read the keypad input on the raspberrypi.

We used this project as our basis(it's in Dutch): https://github.com/ralphcrutzen/PTT-Tafeltjes-Telefoon?tab=readme-ov-file. This project turns the phone into a math game where a child asks you a random times table question and you have to give the correct answer using the rotary keypad. Fred is translating the code to eng. Fred thinks I can't do times tables.

Set up the raspberrypi, named it telephone.(tut here:https://nematicslab.com/how-to-enable-ssh-without-using-a-monitor/)

Fred made me a user(Sevgi) as well and we tested the connections first, adjusted the code accordingly. Fred tested the connections like this (this is the final working version):

import RPi.GPIO as GPIO


GPIO.setmode(GPIO.BCM)
GPIO.setup(23, GPIO.IN, pull_up_down = GPIO.PUD_UP)
GPIO.setup(24, GPIO.IN, pull_up_down = GPIO.PUD_UP)
GPIO.setup(25, GPIO.IN, pull_up_down = GPIO.PUD_UP)

while True:
        
        print('-')
        if GPIO.input(23):
                print('23')
        if GPIO.input(25):
                print('25')
        if GPIO.input(24):
                print('24')

Here is how we set up the wires and the raspberry pi:

Here is the eng version of the dutch code:

#!/usr/bin/env python
import sys, os, time, random, pygame
import RPi.GPIO as GPIO

# translated to english by DeepL and wordfa

# Speaker Function - Play Sound
# Takes a file Path
def say(file):
    pygame.mixer.music.load(file)
    pygame.mixer.music.play()
    while pygame.mixer.music.get_busy() == True:
        continue

# Ask Question for Telefone Letter
def askQuestion(numOne, numTwo):
    print("Wat is", numOne, "x", numTwo,"?")
    say("audio/" + str(numOne) + ".mp3")
    say("audio/keer.mp3")
    say("audio/" + str(numTwo) + ".mp3")
    say("audio/is.mp3")

def getNummer():
    # number of Pulses
    nPulsen = 0
    # Watch Dail or Button
    DialContact = GPIO.input(DialPIN)
    NumberContact = GPIO.input(NumberPIN) # Low if pressed
    while DialContact == False and NumberContact == True:
        DialContact = GPIO.input(DialPIN)
        NumberContact = GPIO.input(NumberPIN)
    # Number Pressed (Selected)
    if NumberContact == False:
        return -1

    # Handle Pulses
    done = False
    while done == False and DialContact == True:
        nPulsen = nPulsen + 1
        startTime = time.time()
        time.sleep(0.1)
        DialContact = GPIO.input(DialPIN)
        # Check time between Pulses
        while done == False and DialContact == False:
            if time.time() - startTime >= 0.2:
                done = True
            DialContact = GPIO.input(DialPIN)
    # Return number
    return nPulsen % 10

    # Tell you when handset is picked up
def handsetCallback(channel):
    print("Handset picked up!", channel)
    # Restart Script
    # Set Up all the IO Stuff
    GPIO.cleanup()
    python = sys.executable
    os.execl(python, python, * sys.argv)

# Name pins
DialPIN = 25
NumberPIN = 23
handsetPIN = 24

# Set Up Pins
GPIO.setmode(GPIO.BCM)
GPIO.setup(DialPIN, GPIO.IN, pull_up_down = GPIO.PUD_UP)
GPIO.setup(handsetPIN, GPIO.IN, pull_up_down = GPIO.PUD_UP)
GPIO.setup(NumberPIN, GPIO.IN, pull_up_down = GPIO.PUD_UP)

# Use an interrupt for the handset, because it can be put down at any time
GPIO.add_event_detect(handsetPIN, GPIO.BOTH, callback = handsetCallback)

# Start audio mixer
pygame.mixer.init()

while True:
    try:
        # Wait for pick up
        print("Wait for pick up...")
        handsetContact = GPIO.input(handsetPIN)
        while handsetContact == True:
            handsetContact = GPIO.input(handsetPIN)
        time.sleep (1)

        # Which times table to practise
        print("Which times table to practise?")
        say("audio/welk.mp3")
        table = getNummer()

        # List to keep track of answered questions
        sums = []
        for som in range(10):
            sums.append(0) # 0 is bad, 1 is goed
        numOfCorrectAns = 0

        while numOfCorrectAns < 10:
            # Set Question?
            numOne = random.randint(1,10)
            while sums[numOne - 1] == 1:
                numOne = random.randint(1,10)

            if table == -1:
                numTwo = random.randint(1,10)
            elif table == 0:
                numTwo = 10
            else:
                numTwo = table
            result = numOne * numTwo
            numOfDigits = len(str(result))

            askQuestion(numOne, numTwo)
            thisDigit = 0
            answer = ""

            # Watch for Answer
            while thisDigit < numOfDigits:
                nummer = getNummer()
                if nummer > -1: # Dial Turned
                    answer = answer + str(nummer)
                    thisDigit = thisDigit + 1
                else: # Number Key Pressed
                    askQuestion(numOne, numTwo)
                    thisDigit = 0
                    answer = ""

            print(answer)

            # Check Answer
            # string to Int Answer
            if int(answer) == result:
                numOfCorrectAns = numOfCorrectAns + 1
                sums[numOne - 1] = 1
                print("Good Job!")
                say("audio/goed.mp3")
            else:
                print("You suck, the correct answer is ", result)
                say("audio/fout.mp3")
                say("audio/" + str(result) + ".mp3")
            print()
            time.sleep(1)
        say("audio/einde.mp3")
    except KeyboardInterrupt: # Ctrl+C
        GPIO.cleanup()