Rotary Dial Phone Revival – 4 – Final

This is the next and final step after dealing with the headset a few weeks ago.

All the main parts were mostly ready, but it still took some effort to put the whole together and make it work reliably.

Not least re-design the handset hook as there was too much friction and the springs were too strong, making the hanging up slightly “awkward”.

Once this was out of they way, I had to re-write the  bit of code that deals with reading the digits from the rotary dial (see part1) as the generated pulses remained unreliable in spite of my debouncing. It turns out simply using the duration taken by the dial to “unwind” is far more reliable, while also being easier.

And here’s the final result, after some plastic case melting and liberal application of hot glue:

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As usual, you can find all the latest code on my Github account but here’s the main Python file for reference:

"""Rotary phone dialer"""

___title___        = "Rotary Phone Dialer"
___license___      = "MIT"
___dependencies___ = ["sleep", "app"]
___categories___   = ["EMF"]

import ugfx, utime, sim800
from machine import Pin
from homescreen import *





##### DIALING #####
dialing = False
calling = False
currentNumber = ""
lastDigit = -1


# for Rising/Falling see ti/boards/MSP_EXP432E401Y.c
pinDialStart = Pin(Pin.GPIO_JOYL, Pin.IN) # PullDown, BothEdges
pinDialPulse = Pin(Pin.GPIO_JOYR, Pin.IN) # PullUp, BothEdges
timeLastStart = utime.ticks_ms()
timeFirstPulse = utime.ticks_ms() 
timeLastPulse = utime.ticks_ms()   


def callbackDialPulse(p):
    global pinDialPulse, timeFirstPulse, timeLastPulse, dialing, lastDigit
    if(dialing and pinDialPulse.value() == 0):
        currentTime = utime.ticks_ms()
        if(lastDigit  40):
            lastDigit = lastDigit + 1
        timeLastPulse = currentTime
        
    
# empiric data, each range centered around mean/avg of empiric durations and is wider than 2 stdevs
# duration between the 1st pulse and the last
def digitByDuration(durationMs):
    if(durationMs < 20):
        return 1
    elif(durationMs < 105):
        return 2
    elif(durationMs < 200):
        return 3
    elif(durationMs < 280):
        return 4
    elif(durationMs < 375):
        return 5
    elif(durationMs < 460):
        return 6
    elif(durationMs < 535):
        return 7
    elif(durationMs < 625):
        return 8
    elif(durationMs  300 and currentTimeMs - timeLastPulse > 200):
        if(pinDialStart.value() == 1 and dialing == False):
            dialing = True
            lastDigit = -1
            timeLastStart = currentTimeMs
        elif (pinDialStart.value() == 0 and dialing == True and lastDigit >= 0):
            dialing = False
            lastDigit = lastDigit + 1
            if(lastDigit >= 10):
                lastDigit = lastDigit - 10
            # check the digit
            digitDurationMs = timeLastPulse - timeFirstPulse
            durationBasedLastDigit = digitByDuration(digitDurationMs)
            # DURATION based digit is much more RELIABLE !  (all interrupts/callback code for not much... 🙂 ) 
            currentNumber = currentNumber + str(durationBasedLastDigit)
            timeLastStart = currentTimeMs
            print("Dialled DIGIT: " + str(lastDigit))
            if(lastDigit != durationBasedLastDigit):
                print(" !!!! Digit mismatch. From duration: " + str(durationBasedLastDigit) + " / " + str(digitDurationMs) + "ms")

            print("# " + currentNumber)
            ugfx.area(5, 90, 120, 20, ugfx.WHITE)
            ugfx.text(5, 90, currentNumber, ugfx.RED)

    #returns 0=ready, 2=unknown, 3=ringing, 4=call in progress
    # after 3 secs from starting a number, take whatever we have and try dialing
    if ((not calling) and hookStatus and sim800.getstatus() == 0 and len(currentNumber) > 0 and currentTimeMs - timeLastStart > 3000):
        calling = True
        ugfx.area(120, 90, 240, 20, ugfx.WHITE)
        ugfx.text(120, 90, "Calling...", ugfx.RED)
        print("Calling... " + str(currentNumber))
        sim800.call(currentNumber)



##### RINGING #####
pinBellEnable = Pin(Pin.GPIO_ETHLED1, Pin.OUT)
pinBell = Pin(Pin.GPIO_ETHLED0, Pin.OUT)
timeLastBellMove = 0
timeLastFreqRefresh = 0
bellFreqHz1 = 60
bellFreqHz2 = 40
bellFreqHz = 0.1
ringBell = False
bellState = 0   # 0 - pause, 1 - ring freq1, 2 - ring freq2


# it would be so much easier to do this witn PWM or a Timer callback !
# however the former is set on given pins and the latter doesn't work 
def updateBell(currentTimeMs):
    global ringBell, timeLastBellMove, pinBellEnable, pinBell, bellFreqHz
    if ringBell:
        pinBellEnable.on()
        if (currentTimeMs - timeLastBellMove > (1000 / bellFreqHz)):
            pinBell.value(not pinBell.value())
            timeLastBellMove = currentTimeMs
    else:
        pinBellEnable.off()

    global bellState, timeLastFreqRefresh, bellFreqHz1, bellFreqHz2
    # change the frequency and update display rarely
    if(currentTimeMs - timeLastFreqRefresh > 1500):
        bellState = (bellState + 1) % 3
        if(bellState == 0):
            bellFreqHz = 0.1
        elif(bellState == 1):
            bellFreqHz = bellFreqHz1
        else:
            bellFreqHz = bellFreqHz2

        ugfx.area(150, 5, 90, 20, ugfx.WHITE)
        ugfx.text(150, 5, "Ring " + str(bellFreqHz) + "Hz" , ugfx.RED)
        timeLastFreqRefresh = currentTimeMs
    

# # Change freq of ring
# pinJoystickDown = Pin(Pin.GPIO_JOYD, Pin.IN) # PullDown, BothEdges       

# def callbackJoystickDown(p):
#     global bellFreqHz
#     if(bellFreqHz > 10):
#         bellFreqHz = bellFreqHz - 10
#     else:
#         bellFreqHz = 80

# # external interrupts from the Joystick
# pinJoystickDown.irq(handler=callbackJoystickDown)



##### PHONE #####
print("INIT PHONE START")

sim800.poweron()
sim800.btpoweron()

# Start the Bluetooth Headset IF necessary
if(not sim800.btconnected()):
    print("BT Headset not connected")
    pinBTHeadsetOnOff = Pin(Pin.GPIO_FET, Pin.OUT)
    pinBTHeadsetOnOff.off() # take that Pin DOWN same as if someone was pressing the power button on the headset
    utime.sleep(3)   #wait 3 secs for the BT Headset to start
    pinBTHeadsetOnOff.on() #that was all now

    sim800.btconnect(sim800.btPairedIdForName("S6"), 6)

print("INIT PHONE DONE")

def updatePhone():
    global ringBell, hookStatus, calling
    if sim800.isringing():
        ringBell = True
        if hookStatus:
            sim800.answer()
    else:
        ringBell = False
        # status == 4 means call in progress
        if ((not hookStatus) and (sim800.getstatus() == 4)):
            sim800.hangup()
            calling = False


##### General INFO : BATTERY & BT #####
timeLastInfoRefresh = 0
def updateGeneralInfo(currentTimeMs):
    global timeLastInfoRefresh, hookStatus
    if(currentTimeMs - timeLastInfoRefresh > 10000):
        ugfx.area(5, 5, 120, 20, ugfx.GRAY)
        ugfx.text(5, 5, "Batt " + str(battery()) + "%" , ugfx.WHITE)
        connBtDeviceNames = list(map(lambda e: e[1], sim800.btconnected()))
        ugfx.area(5, 30, 235, 20, ugfx.GRAY)
        ugfx.text(5, 30, "Bt Cn " + str(connBtDeviceNames), ugfx.WHITE)
        ugfx.text(120, 30, "Hk " + str(hookStatus), ugfx.WHITE)
        timeLastInfoRefresh = currentTimeMs
        


##### HOOK On/Off #####
pinHook = Pin(Pin.GPIO_JOYU, Pin.IN) # PullDown, BothEdges  
hookStatus = False
hookTimeLastToggle = 0
def updateHook(currentTimeMs):
    global hookStatus, hookTimeLastToggle, currentNumber
    if(currentTimeMs - hookTimeLastToggle > 100):
        newHookStatus = bool(pinHook.value())
        if(newHookStatus != hookStatus):
            hookStatus = newHookStatus
            
            currentNumber = ""  #reset number dialed
            ugfx.area(5, 90, 235, 20, ugfx.WHITE)

            hookTimeLastToggle = currentTimeMs
            print("Hook: " + str(hookStatus))
               



##### MAIN #####
# initialize screen
ugfx.init()
ugfx.clear()
ugfx.backlight(0)
ugfx.text(5, 60, "NUMBER", ugfx.BLACK)



# MAIN loop
while True:
    currentTimeMs = utime.ticks_ms()

    updateDial(currentTimeMs)

    updateBell(currentTimeMs)

    updatePhone()

    updateHook(currentTimeMs)
    
    updateGeneralInfo(currentTimeMs)