Repairing a Vendo V-80 cola dispencer of the 1950s

Yeah, there is a whole series of mods that can be hacked into the machine. First I could replace the mechanical switches with sensors (optical or magnetic), the cooling thermostat and motor controls are other candidates for modification.

I can't use the current actuators for low voltage though. The state of the contacts and the amount of bounce is dazzling. It works to activate the 110 V relais, but no chance to get a decent 3.3 or 5V signal.

Some action photos:

measuring the motor circuit:

coin detector

detector proto

Some hardware:

my proto code

/*
// vento V-80 controls
// no copyright jc 2014
 */

// the actuator relais that will engage when coin is detected
#define RELAIS 8 
// the analog input signal from IR detection circuit
#define IR 0
// how long is the relais actuated when coin detected
#define PULSE_WIDTH 750
// at this level (from 0 to 1023) we consider the IR channel interrupted
#define THREASHOLD 450
// status led
#define RELAIS_STATUS_LED 12
#define IR_STATUS_LED 10




// the setup function runs once when you press reset or power the board
void setup() {
  // initialize the relais pin, so thzt it always assumes not-engaged status at startup and reset
  pinMode(RELAIS, OUTPUT);
  digitalWrite(RELAIS, LOW);
  // mark the infrared detection pin as input input
  pinMode(IR, INPUT);
  // mark the status led as output
  pinMode(RELAIS_STATUS_LED, OUTPUT);
  digitalWrite(RELAIS_STATUS_LED, LOW);
  pinMode(IR_STATUS_LED, OUTPUT);
  digitalWrite(IR_STATUS_LED, LOW);
  
  
  // debug settings
  Serial.begin(9600);
}


// the loop function runs over and over again forever
void loop() {
  
  // when a coin is detected, we actuate the relais for the time defined by THREASHOLD
  if (detectCoin()) {
    digitalWrite(RELAIS, HIGH);
    digitalWrite(IR_STATUS_LED, HIGH);
    digitalWrite(RELAIS_STATUS_LED, HIGH);
    delay(50); // pulse the coin detect led for a moment
    digitalWrite(IR_STATUS_LED, LOW);
    
    delay(PULSE_WIDTH - 50); // keep the relais engaged for the THREASHOLD time, minus the time that we've spent on flashing thr coin led
    digitalWrite(RELAIS, LOW);
    digitalWrite(RELAIS_STATUS_LED, LOW);
  }

}




/* 
  return TRUE when we detect that the IR channel in disturbed (i.e.: a coin is passing through it)
  That is the case when the voltage presented on analog pin IR drops below THREASHOLD.
*/  
  
bool detectCoin() {
  // measure the voltage of the IR circuit
  int iSensorValue = analogRead(IR);
  
  // debug info
  char output[80];
  sprintf(output, "Sensor: %d\n", iSensorValue);  
  Serial.print(output); 

  // if the detected voltage is below THREASHOLD, a coin is passing through the channel  
  return (iSensorValue < THREASHOLD); // there is something in the IR path
}

Jan -

If you're willing to blog about the project, we'll be happy to look at supplying you the parts.  The "Internet of Cola" isn't a bad title (thanks Peter!)

Best Regards, Christian

Jan -

If you're willing to blog about the project, we'll be happy to look at supplying you the parts.  The "Internet of Cola" isn't a bad title (thanks Peter!)

Best Regards, Christian