Make Money With Arduino

**** ENTERED IN THE HURRICANE LASERS CONTEST****
What would I do with a Laser Cutter? Build Simple Robotic Kits to teach people a Hobby that I Love.

Ever wanted to make some money from your projects?
This Instrutable will show you how to Simply interface a coin selector with your Adruino.
And also how to then connect that to your Visual C# Project.
Then it's all up to you and that great idea you have, if it's electronic or a program/game,
The Buck Starts Here.


You will need:
A Coin Selector: There are many different type's, the CH-926 accepts the most amount of coins so thats what I'll be using.
UK Stock, US Stock

Any 12v Power Supply, Batteries or Wall Wart.

An Arduino UNO

Microsoft Visual Express 2010 C#: Free Download, Scroll down until you see the correct option.
Note: Only needed for a coin operated Program, Not electronics Projects.

Let's get Started!

Step 1: Coin Sampling

For your Coin Selector to know what type of coins it accepts, you have to set it up and then feed it samples of those coins.
It is recommend to sample at least 15 coins of the same type, up to a maximum of 30. Don't feed the same coin through 30 times, it's make the selector to fussy about what it accepts.

A Coin Selector works by comparing the material, weight and size of coins past through it to the samples you provide. If a coin is not reconised it drops out the return slot, if it is reconised the Unit sends out pulse's on the "COIN" line.
So to make it easier for the programming side we use a "greatest common factor" rule.
eg. We'll use the following coins (UK) 5p, 10p, 20p, 50p,& £1, (US) 5c, 10c, 25c, 50c & $1.
All the the coins can be made up with multiple 5p or 5c coins, so we make 1 pulse equal to 5p or 5c.
5p/c = 1 pulse, 10p/c = 2 pulses, 20p = 4 pulses, 25c = 5 pulses, 50p/c = 10 pulses, £/$1 = 20 pulses.

Now, TheSetup:

First the switches...
select "NC" by sliding the top switch to the bottom position.
select "FAST" by sliding the bottom switch to the top position.

Power Up the unit with a 12v supply.

1. Hold the "ADD" and "MINUS" buttons down at the same time for about 3 seconds, release and then the letter "A" will appear on the LED display.
2. Press the "SETUP" button once, and the letter "E" will appear. Then use the "ADD" and "MINUS" buttons to choose how many kinds of coins your going to use. Press the "SETUP" button again to finish.
3. The letter "H" will appear. Use the "ADD" and "MINUS"buttons to choose how many sample coins your going to feed it later. Press the"SETUP" button again to finish.
4.  The letter "P" will appear. Again use the "ADD" and "MINUS" buttons to choose the amount of output pulses you want. Press the "SETUP" button to finish. Refer to the above example to determine number of pulses.
5.  The letter "F" will appear. Using the "ADD" and "MINUS" buttons, choose the accuracy. The value is from 1 to 30, with 1 being the most accurate. I use 10 and it works fine. Again "SETUP" to finish.

You have now setup the first coin, depending on how many coins you selected in step 2, you'll have to repeat Step's 3 to 5 for each one.
The letter "A" will appear when you've setup all the coins. Hold "SETUP" for 3 seconds to finish, the letter "E" will appear.
Finally, switch the unit off and then back on.

Sampling time:

1.  Hold the "SETUP" button down for about 3 seconds, release and then the letters "A1" will appear on the LED display. This is your first coin (5p/c)
2. Feed the Coin Selector your sample coins, the LED display will show the amount of coins you've entered. "A1" will appear again when finished.
3. Hold the "SETUP" button down again for about 3 seconds, release and then"A2" will appear, repeat these steps until all coins are sampled.

If your not using all of the coin types available (eg 5 coins of a 6 type coin selector) the unit will ask for samples of a coin type you haven't setup, just hold the "SETUP" button down for 3 secconds of each of the remaining coins.

The Coin Selector restarts itself and is now ready to connect to the Arduino.

Step 2: Arduino Time

To Wire the Coin Selector to the Arduino is easy.

The white "COIN" Wire from the Selector connects to pin 2 on the Arduino. It has to be pin 2 or 3 as these are Interrupt pins.

Now if your using a different power supply for the Coin Selector to the Arduino, you must connect a common Ground. So the Red wire from the Coin Selector connects to +12V of the supply and the Black wire to ground of the supply AND to ground of the arduino.
Note: USB will NOT power the coin selector.

Step 3: Some Simple Code

Now, Fire up the Arduino IDE and let start coding:
PROGRAM START:

const int coinInt = 0; 
//Attach coinInt to Interrupt Pin 0 (Digital Pin 2). Pin 3 = Interrpt Pin 1.

volatile float coinsValue = 0.00;
//Set the coinsValue to a Volatile float
//Volatile as this variable changes any time the Interrupt is triggered
int coinsChange = 0;    
//A Coin has been inserted flag

void setup()
{
  Serial.begin(9600);  
//Start Serial Communication
  attachInterrupt(coinInt, coinInserted, RISING); 
//If coinInt goes HIGH (a Pulse), call the coinInserted function
//An attachInterrupt will always trigger, even if your using delays
}

void coinInserted()   
//The function that is called every time it recieves a pulse
{
  coinsValue = coinsValue + 0.05;  
//As we set the Pulse to represent 5p or 5c we add this to the coinsValue
coinsChange = 1;   
//Flag that there has been a coin inserted
}

void loop()
{
  if(coinsChange == 1)         
//Check if a coin has been Inserted
  {
    coinsChange = 0;        
//unflag that a coin has been inserted

    Serial.print("Credit: £");
    Serial.println(coinsValue);    
//Print the Value of coins inserted
  }
}

PROGRAM END!

This simple program will write the total value of coins inserted to the serial monitor.
If you'd like your project to start automatically after say 50p or 50c has been inserted then replace:

    Serial.print("Credit: £");
    Serial.println(coinsValue);

with:

  if(coinsValue >= 0.50)
  {
          //your code here, eg Big Flashing Lights!!!! and Serial.println("I'M MAKING MONEY!!!!");
  }

CONGRATULATIONS
The Electronics Side is finished, Continue if you want to Interface with a Window Application you've created

Step 4: Basic Windows Form Application

Load up Microsoft Express 2010 and create a new "Windows Form Application".
I'm calling mine Coin Selector.

Now to your form add the following components:
1. A Button, Change the Text to "Connect"
2. A Text Box, Change the Text to "0.00"
3. A Serial Port, Change the PortName to the COM Port your Arduino connects to.

Step 5: Coding Time

Double Click the "Connect" Button and you'll open the Code window, paste the following code in the brackets:

if (button1.Text == "Connect")   //If the button say's connect
{
  serialPort1.Open();             //Open Serial Port
if (serialPort1.IsOpen)         //If the Port Opens
{
button1.Text = "Disconnect";    //Change the Button to Disconnect
                     this.serialPort1.DataReceived += new System.IO.Ports.SerialDataReceivedEventHandler(this.serialPort1_DataReceived);
      //Adds an Event when the serial port receives data
} 
}
            else
            {
                serialPort1.Close();            //Close the Serial Port
                button1.Text = "Connect";    //Change the Button to Connect
}


We have to add a few functions, the first will close the port if we close the application. The second tells the program what to do if data is received and the third is what it does. So Just below the final "}" of "button1_Click"
add the following:

//CLOSE PORT ON EXIT
        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (serialPort1.IsOpen)
            {
                serialPort1.Close();
            }
        }

//SERIAL DATA RECEIVED EVENT
        private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
        {   //serialPort1 runs in a different thread, to call a function in the main code Invoke must be used
    this.Invoke(new EventHandler(serialReceived));  //Calls the below function
        }
        private void serialReceived(object sender, EventArgs e)
        {
                double coinsValue = Convert.ToDouble(textBox1.Text);  //converts the text to a number
coinsValue = coinsValue + 0.05;          //Add 0.05 to that number
textBox1.Text = Convert.ToString(coinsValue);     //Converts it back to text and puts it back in the textbox          
        }

Now, Scroll up and you'll see some "using" lines, add "using System.IO.Ports;" as we'll be using Serial port functions.

The Basic Program is finished, On the Arduino side:
replace...
    Serial.print("Credit: £");
    Serial.println(coinsValue);
with...
Serial.print(0);  //Sends 1 piece of data over the Serial, the windows program add's 0.05 for every piece (println would send 3)

Upload, Run the windows Application, Click "Connect" and your away!

Step 6: CONGRATULATIONS

You can now activate your projects by receiving the right amount of money!

Good Luck & when your a Millionaire please send me some!

Comments

[markvovo]

Does the mechanism have a refund option? What happens to the COIN pulses if you press the button on the front? I have one ordered, but won't be here for another couple of days.

[Skipped]

Hey markvovo, There is no refund option. The button on the front mechanically opens the sensor section of the selector to release jams, these jammed coins drop back into the return slot. The pulses start when they have past this setcion so you'll only get Coin Pulses once actually receiving a coin.
Good luck with your project.

[BastelPichi]

If you are out of stock, some units have an SET pin header, bridging both pins makes it refuse any coin.

(just for the archive, i know this is 10 years old)

[Bonecaya]

Excellent instructable!.

A refund option could be mechanical. Coins that pass through the counter are collected in a small bin. The customer makes their selection and the coins are dropped into a bucket. If they don't make a selection and select a refund, the coins are dropped out to a refund cup on the outside of the machine... A small servo could activate the midpoint bin, one direction for keep, another for refund.

[Skipped]

Very True, I'll have to try this. There is enough (All bar 1) spare pins on the Arduino to try use up ;-) Thats for your input.

[Hodgeypodge]

I also had issues with noise, like many others, even while using the internal pull-up.
Static
electricity, touching the cables or tapping the transformer causes
pulses to be read. But the main issue was on average one in every 10
coins would have a pulse too many.

A solution I've found is to modify the ISR coinInserted() slightly by adding an if statement.

void coinInserted() {

if(digitalRead(2)== LOW) {
coinsValue = coinsValue + 0.05;
coinsChange = 1;
}}

This resolves all the false reads that I get, including on startup.

(Note
my coin acceptor (CH926) connects to an internally pulled up pin and
pulses down to ground so I have my attachInterrupt at "Falling" and the
idle state of the COIN cable is set to Normally Open (NO). You need to
adjust the code if your acceptor works differently, and it may be less
effective I haven't tested it.)

Solution stolen from this fantastic guide http://blog.deconinck.info/post/2017/02/25/CH923/CH926/CH928-coin-acceptor-features-and-caveats

[KNERD_UNO]

Maybe try a grounded power supply

[Mistablik]

I ran into a pretty big problem with static electricity in my application. Sometimes you could shock the front plate and it would count for a pulse or two, giving you false money. I modified the code slightly. You'll also need to set each coin to pulse one more time than normal. For instance, make nickles pulse 2 times instead of one. Then use this code:

const int coinInt = 0;

//Attach coinInt to Interrupt Pin 0 (Digital Pin 2). Pin 3 = Interrpt Pin 1.

int oldMillis = 0; //set first old time to 0

volatile float coinsValue = 0.00;

//Set the coinsValue to a Volatile float

//Volatile as this variable changes any time the Interrupt is triggered

int coinsChange = 0;

//A Coin has been inserted flag

int currentMillis = 0; //define currentMillis

void setup()

{

Serial.begin(9600);

//Start Serial Communication

attachInterrupt(coinInt, coinInserted, RISING);

//If coinInt goes HIGH (a Pulse), call the coinInserted function

//An attachInterrupt will always trigger, even if your using delays

}

void coinInserted()

//The function that is called every time it recieves a pulse

{

//As we set the Pulse to represent 5p or 5c we add this to the coinsValue

coinsChange = 1;

unsigned long currentMillis = millis(); //check current time

int difference = currentMillis-oldMillis; //find difference between last pulse time //and current pulse time

//Serial.print("Millis: ");

//Serial.println(difference);

oldMillis = currentMillis; //set old pulse time

if(difference < 152 && difference >148){

//unless the pulse time was in between the numbers above, it won't count for //money

coinsValue = coinsValue +0.05;

coinsChange = 1;

}

//Flag that there has been a coin inserted

}

void loop()

{

if (coinsChange == 1){

Serial.print("Money: $");

Serial.println(coinsValue);

coinsChange = 0;

}

}

[KNERD_UNO]

Sounds more like a grounding issue on the power supply. Should of used a commercial power supply with a ground instead of a Wall Wart

[tanjamaya]

Ok. now I get it... It works great... Thanks... In arduino code I change

this line

volatile float coinsValue = 0.00

whith line

volatile int coinsValue = 0

also this line

if(difference < 152 && difference >148)

with this

if(difference < 200 && difference >100){

and this line

coinsValue = coinsValue +0.05;

whit this line

coinsValue = coinsValue +10;

In coinAcceptor Settings I chandge the pulses...

before 10denars was 1 pulse, after 10 denars is 2 pulses

also before 50denars was 5 pulses, after 50 denars is 6 pulses

and now it works great.

Thanks a lot you saved me :)

[ptavaressilva]

Great code @Skipped, thanks! Love the fact that you commented so well and that it worked practically out of the box.

At first the behaviour was erratic, but once I added:
pinMode(2, INPUT_PULLUP);
to setup(), to turn on the pull-up of D2, it worked perfectly.

When you turn on/off the coin acceptor there is noise on the COIN line, so you may need to wait and reset credit after powering up the Arduino, to avoid generating credit due to race conditions (especially if you use different power supplies for the Arduino and the acceptor).

I'm using it on a vending machine I'm making. Will share on releasetheinnergeek.com when done.

[Hodgeypodge]

See my comment about removing noise, it may help you with the startup noise. I don't have any with the solution.

[KNERD_UNO]

I have seen a 10k resistor connected in parallel to the circuit. Using that diagram, I am not seeing any noise. It seems the resistor is to make sure the circuit is clearly open or closed.

[Hodgeypodge]

Ah, that's a much more elegant solution if it indeed works. I can't test it as I no longer have it but good for posterity

[Chimera_Byte]

Back to basics. What worked for me was inserting bypass capacitors in the 12VDC power supply. If your 12VDC is not well regulated, white wire signal will be unreliable!

[KNERD_UNO]

You need a 10k resistor in the count circuit in parallel to produce a clear logic signal to the Arduino. Something which was not included in this Instructable

[KNERD_UNO]

After playing around with a similar setup, I noticed even the faster Arduino Nano is just too slow to respond. If the coins are put into the acceptor too fast, it throws the Arduino count way off, and it cannot recover, and any subsequent coins accepted are not counted.

With that, I am going to try with the ESP32 with dual core 200Mhz CPUs. However, the ESP32 uses 3.3 volts.

Thanks for putting up that site. I see you are using a Voltage level shifter which tells me the coin acceptor is putting out 5 volts for the pulses.

Also, the noise you experiencing is because there needs to be a 10k resistor in parallel in the count circuit to produce a clear logic state.

[ufftata]

error x8

/CLOSE PORT ON EXIT
private void Form1_FormClosing(object sender, FormClosingEventArgs e)

{

if (serialPort1.IsOpen)

{

serialPort1.Close();

}

}


//SERIAL DATA RECEIVED EVENT
private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)

{//serialPort1 runs in a different thread, to call a function in the main code Invoke must be used
this.Invoke(new EventHandler(serialReceived));//Calls the below function
}

private void serialReceived(object sender, EventArgs e)

{
double coinsValue = Convert.ToDouble(textBox1.Text); //converts the text to a number
coinsValue = coinsValue + 0.05;//Add 0.05 to that number
textBox1.Text = Convert.ToString(coinsValue);//Converts it back to text and puts it back in the textbox
}


Now, Scroll up and you'll see some "using" lines, add "using System.IO.Ports;" as we'll be using Serial port functions.


The Basic Program is finished, On the Arduino side:

replace...
Serial.print("Credit: £");

Serial.println(coinsValue);

[ufftata]

this.serialPort1_DataReceived error

[ufftata]

program code no work 8errors ....