Tutorial Another ButtonBox (Arduino UNO)

marc burns · Nov 17, 2018

i got a arduino uno r3... 2 pcf8574 but cant get buttons to work.... what pcf8574 library was used???....

Mitch.SRD · Dec 14, 2018

Great thanks for the sharing.

I just received Arduino UNO R3 i bought and it appears the error when i was trying to verify.

Arduino: 1.8.5 (Mac OS X), Board: "Arduino/Genuino Uno"

/Users/Mitch/PS4_ButtonBox/PS4_ButtonBox.ino:63:21: fatal error: pcf8574.h: No such file or directory
#include <pcf8574.h>
^
compilation terminated.
exit status 1
Error compiling for board Arduino/Genuino Uno.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Do you perhaps know the reason ?

Cant wait to get button box run on my PS4

vthinsel said: ↑

Hello,

I wanted to share with you my USB ButtonBox, which I made with Project Cars on PS4 in mind.

The design is quite simple and requires few things:
- An arduino UNO : be careful, as it must have the small Serial/USB AVR located on the top left part (with USB connector on the left). This is an Atmel Atmega16U2 or Atmega8U2 . Some clones do not have it.
- Two I2C I/O extender to make a 8x8 matrix in order to have upto 64 buttons I'm using some cheap PCF8574
- Push buttons, start button (all NO ,normally open)

Key Concepts:

Turn the arduino to a keyboard : The ATmega16U2 chip (top left) on the Arduino board acts as a USB/serial interface allowing programming through USB. It runs a software like any AVR implemeting serial/USB conversion that can be updated through a special usb protocol called DFU (Device Firmware Update). Some other software will allow you to turn the ATmega16U2 into a USB HID (keyboard, mouse, or any Human Interface Device). Be careful: when USB HID code is uploaded on the ATmega16U2, programming the arduino becomes impossible unless you revert to the original ATmega16U2 code (or program using an AVRISP programmer) So program the arduino first, then the ATmega16U2 using procedure describded here and the firmware Arduino-keyboard-0.3.hex attached to this post.

Button matrix : the arduino has only a few pins available. Not enough to make a decent button box upto 64 buttons. Using an Arduino Mega would be overkill, so we need to be smart and use a matrix. A button is not attached to one pin but to two pins organised in row / column. To detect a keypress, we need to find the col/row making the code a bit longer than just checking the pin low/high state. We are using 2 I2C PCF8574 daisychained in order to make a 8x8matrix. Each PCF8574 is assigned a different I2C address resulting in two slave address. Only 4 wires (SDA/SCL/+5V/GND) are used on the arduino. Easy part

The difficult part : soldering. Once the buttons are mounted, you need to implement the row/col matrix. To make things easier, I decided to have 8 columns to make wiring more straightforward. I started by wiring rows using unprotected wire, then I moved onto column soldering without making shortcuts by using some stripped insulant. Note the A0 jumper on rows .

The code also implements a keypress repeat : leave a button pressed for 400ms and it will be repeated quickly every 30 millisec

Steps:
- I glued a millimeter paper onto 3mm plywood and made some holes with a dremel. Then drill the proper pushbutton diameter and mount all buttons (apply a 3M carbon look before if you need). Align all buttons connectors to make soldering more easy.

- Implement the matrix as describded earlier
- Upload arduino sketch
- Program ATmega16U2
- Done

Maybe I'll rework the sketch to avoid using I2C extenders, as you may not neet 64 buttons, like in my example (8 col / 4 rows)

Works great with PCars on PS4, but not with Dirt Rally as it doesn't support (yet.. I hope) additionals USB keyboards

Enjoy !
Click to expand...

Mitch.SRD · Dec 14, 2018

i guess im having the same problem you encountered. would you mind to share the correct file for PCF8574 library ?

Thanks heaps!!

Andi4x4 said: ↑

Finally !

Got it sorted - the PCF8574 library I had was not suitable, so, a couple of hours spent trawling the internet eventually yielded one that did, then issues with the Atmel Flip flash software slowed me down another couple of hours.

Now, however, just over 4 hours later, it is all working !

Yay !

Button box construction is well under way - box is drilled, carbon effect vinyl applied, switches fitted - just gotta solder it all up !

Will take some pics and start a separate thread for that in the appropriate place !

But now - well deserved Bed Time !
Click to expand...

vthinsel · Dec 17, 2018

This one is a funny one.
I have attached the lib I use but it failed to compile properly.... I had to replace the #include <pcf8574.h> in my code by #include <PCF8574.h>
Strange it is case sensitive now.... maybe the latest arduino compiler is more touchy about upper.lower case as in Unix

Mitch.SRD · Dec 18, 2018

Nice one... mate.

Can I wire the button straight onto UNO board even without 2 I2C PCF8574, thinking I might just do a simple one instead in order to suits my purpose. If so, do you perhaps have a quick diagram ?

Cheers.

vthinsel said: ↑

This one is a funny one.
I have attached the lib I use but it failed to compile properly.... I had to replace the #include <pcf8574.h> in my code by #include <PCF8574.h>
Strange it is case sensitive now.... maybe the latest arduino compiler is more touchy about upper.lower case as in Unix
Click to expand...

vthinsel · Dec 18, 2018

a quick search on google gives this : https://www.arduino.cc/en/Tutorial/Button

Log in or Sign up

Tutorial Another ButtonBox (Arduino UNO)

marc burns New Member

Mitch.SRD New Member

Mitch.SRD New Member

vthinsel Well-Known Member

Attached Files:

PCF8574.zip

Mitch.SRD New Member

vthinsel Well-Known Member