COIN-OP: mini arcade cabinet photos

The completed COIN OP ARCADE machine (with missing only coins drawer)

The interior (with back cover removed):

In the upper part is located the usb pc speakers.

In the bottom side is visible the temporary ... coin storage solution.

Don't miss the Arduino uno keyboard previous series of posts.

Update 2016/11/23: check out sheet metal plate upgrade and coin drawer window on this post

COIN-OP: mini arcade cabinet build log 3/3

This is a 3 part post, in which i cover:

INTRODUCTION Arduino Uno Keyboard emulator - dfu mode / programming
SKETCH Arduino Uno keyboard emulator - ino sketch
COINS Coin acceptor (3 coins)

Source code is available on Google Drive folder:
SOURCE CODE

COIN ACCEPTOR
I use this model by SparkFun: CH-923 sourced at Robot Italy.
The device is a robust independent coin acceptor with more than 95% coin recognition performance.
Here after the manual:

Is possible to use 1, 2 or 3 coin types. Each time an unrecognised coin is inserted the acceptor ejects it in the front.
If recognised, the coin drop from the bottom.


Voltage is +12Vdc sourced from the PC ATX connector (Yellow for 12V, Black for GND). Output is TTL compatible so you can use directly with arduino. You need only to interconnect GND from PC to GND to the Arduino part.

The output is programmable, so each time you insert a coin you can choose how many pulses the Acceptor are sent to the Arduino.

Because i use Euros coins, i've set 10 cents / pulse:
20 euro cents: 2 pulses
50 euro cents: 5 pulses
1 euro: 10 pulses
You can use a metal coin of your choice, and once programmed it will works with your coins.

On the Arduino Uno part i've connected the Grey wire to Pin 2 (INTERRUPT 1) acting as a switch using a 10k pulldown resistor. Each time a pulse is received an internal counter is incremented by 0.10 euro.
In the main loop each time the counter is > than 20 cents, is decremented by 20 cents and a keystroke is sent to PC.
The corresponding keystroke is then mapped on Mame as coin insert.

The sketch part is really simple:

• Declare coinvalue variable as volatile so you can change in interrupt routine
• Attach in Setup the interrupt handler using: attachInterrupt(digitalPinToInterrupt(PIN_COIN), coinInserted, FALLING);
• Handle the interrupt incrementing the coinvalue variable, and setting coinchange bool to 1.
• In the loop - once the coinchange value is set to 1 - decrement the coinvalue variable and send the keystroke as described in the previous post. Because the Byte is shared with Start and Menu routine, immediately send the keystroke to clear the byte usage for the latest Start/Menu routine.

The coin acceptor up to now was really reliable, so the arduino keyboard.

Customize it as you need.

COIN-OP: mini arcade cabinet build log 2/3

This is a 3 part post, in which i cover:

INTRODUCTION Arduino Uno Keyboard emulator - dfu mode / programming
SKETCH Arduino Uno keyboard emulator - ino sketch
COINS Coin acceptor (3 coins)

In this post is covered for convenience the Arduino sketch part.

The sketch uses a simple Serial.write(buf) to send a keystroke / keyrelease for each switch, like
Serial.write(buf, 8); // Send keypress

The HID message sent in the serial part is a byte array:
uint8_t buf[8] = { 0 };

Byte 0 is a modifier bye. If you set a bit with another keypress, you will have a combination like CTRL-X.

Modifier keys:
Bit 0 - Left CTRL
Bit 1 - Left SHIFT
Bit 2 - Left ALT
Bit 3 - Left GUI
Bit 4 - Right CTRL
Bit 5 - Right SHIFT
Bit 6 - Right ALT
Bit 7 - Right GUI

Byte 1 - Not used

The useful part starts from byte 2 up to byte 7, where are mapped the HID active key usage codes. This accepts up to 6 keys being pressed at the same time.

Because i have more than 6 keys, i had to join more than one key in each byte. In this situation the same byte is used to send KEY_UP or KEY_DOWN: this works because the switches are inside a joystick and cannot be sent at the same time.

This is my mapping, modify as you require your situation (S1 means Switch 1):

#define PIN_UP 6
#define PIN_DOWN 4 
...

My joins are:
Byte 2: PIN_UP & PIN_DOWN
Byte 3: PIN_LEFT & PIN_RIGHT
Byte 4: PIN_S1 & PIN_S5
etc...
Byte 7: PIN_START & PIN_ESC & PIN_COIN

This mapping helps to send joystick on upper left (PIN_UP + PIN_LEFT) while pressing a fire switch (PIN_S1) and jump switch . Less attention needs the Start/Select and Exit switch.

Each time the loop function finds a specific pin press, in the buffer is wrote the key code. 
To send the keypress "Enter" write 0x28 into the buf, using this code:
buf[2] = 0x28; //Or define a variable for convenience

To emulate a key release: buf[2] = 0;

More HID Keyboard codes could be found at this link

Debounce: I carefully tested the sketch on debounce matter. With simple timing check, a debounce routine is not needed at all.

In the next part i'll cover the coin acceptor part.

COIN-OP: mini arcade cabinet build log 1/3

This is a 3 part post, in which i cover:

1. INTRODUCTION Arduino Uno Keyboard emulator - dfu mode / programming
2. SKETCH Arduino Uno keyboard emulator - ino sketch
3. COINS Coin acceptor (3 coins)

Source code is available on Google Drive folder:
SOURCE CODE

INTRODUCTION

Finally i had the opportunity to complete the Arduino Uno Keyboard emulator, including the Coin Acceptor (3 coins) from Sparkfun (SPARKFUN COM-11719).
After some tweaking the emulator works like a charm.
I had some trouble with key press & release, because we need to leave to OS the key repeat function.
The current version works very well with Mame on Windows 98.

The Keyboard HID hex is based on LUFA and is needed to make Arduino Uno act as a Keyboard, Joystick, Mouse, etc: for more information, check this link Arduino UNO Keyboard HID version 0.3 from darran
There is a copy attached also to this post. Please use at your own risk, this is working for me, but i cannot guarantee for your hardware.

A note: while using keyboard LUFA hex, pins 0 and 1 (TX and RX) will not work as digital pin, so don't use them.

• Start reading this hackaday post (http://hackaday.com/2012/06/29/turning-an-arduino-into-a-usb-keyboard/).
• Install a dfu-programmer (https://www.arduino.cc/en/Hacking/DFUProgramming8U2). I have installed a port for Mac and it works very well with super user privileges.
• Connect Arduino to USB port.
• Upload your keyboard sketch as usual.
• Copy from source in the same directory of the sketch the hex files.
• Enter in DFU Mode (is more simpler then expected): take a screwdriver and short for a moment the two pins in the next photo:

• From terminal, change directory to the sketch dir, and execute:
• sudo dfu-programmer atmega16u2 erase
• sudo dfu-programmer atmega16u2 flash --debug 1 Arduino-keyboard-0.3.hex
• sudo dfu-programmer atmega16u2 reset
• Disconnect and reconnect usb

If you want to revert Arduino to usb bootloader to update the sketch (this is the tricky part), simply repeat these steps:

• Disconnect and reconnect usb
• From terminal, change directory to sketch dir, and execute:
• sudo dfu-programmer atmega16u2 erase
• sudo dfu-programmer atmega16u2 flash --debug 1 Arduino-usbserial-atmega16u2-Uno-Rev3.hex
• sudo dfu-programmer atmega16u2 reset
• Disconnect and reconnect usb

The dfu mode is always available, i never had trouble with this.

In the next post, i'll cover the keyboard sketch to make the Arduino working.