Arduino on the KK2 Multicopter controller

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UPDATE: this article was originally written to work with Arduino 1.01 and the KK2.0.
The KK2 is now up to 2.1 it has an ATMega624 and a slightly different I2C gyro (demo program is not updated for this yet). I have updated the document to work with the newer KK2 however I recommend that you still use the older version of Arduino.

Originally designed for multi rotors, the KK2 Multicontroller makes for a very cheap Arduino compatible board with a little bit of hacking.

For $30 you get an ATMega324 MCU, a 128x64 graphical LCD, 4 buttons, 14 GPIO pins, 3 axis gyroscope and 3 axis accelerometer.

The kk2.1 has an or ATMega644 which has twice the amount of Flash, Ram and EEProm storage on board.

Great for any motion based project that requires a simple user interface.

Read on...

Video demonstrating the Arduino test code.

Detailed explanation of the Arduino test code.

Hacking the Arduino IDE.

UPDATE: Robert and Erikas had pointed out that I made a few errors in this tutorial. (Thanks guys) Fortunately they figured it out. I have since made some changes so hopefully no more mistakes here.

If you have not already got one you can buy the KK2 from HobbyKing. They are popular and sometimes out of stock so here are a few links:

KK2 Multi-rotor LCD Flight Control Board

KK2 Multi-rotor LCD Flight Control Board (AUS Warehouse)

KK2Multi-rotor LCD Flight Control Board (UK Warehouse)

You will also need a USBasp programmer.

Important note:

The Arduino IDE codebase is still changing and currently is up to version 1.5. This is mainly to support the newer Due and Leonardo boards.

This tutorial was tested using Arduino 1.01 which can be downloaded from the Arduino download page.

Seeing as your are messing with the IDE it is probably better to keep Arduino 1.01 as a separate copy of the program just for working with the KK2.

I cannot guarantee that this tutorial will work with other versions of Arduino, feel free to try but I see no advantage as yet.

Step 1 Install Arduino 1.01 and the USBasp drivers if needed.

Arduino 1.01 can be downloaded from the Arduino download page.

I suggest renaming the App to Arduino1.01.app if you want to run it along side a newer arduino version.

Drivers for the UBSasp programmer are not needed for OSX or Linux. Windows follow the instructions in my previous article.

Step 2 edit boards.txt

To find the boards.txt file.

On OSX control click on Arduino.app then show package contents.

then navigate to Contents/Resources/Java/hardware/arduino

For windows the boards.txt file is under hardware/arduino in the arduino program directory. Open it with wordpad as it handles the unix carriage returns better than notepad.

Add the following section to the top of the boards.txt file and save it. Tip: windows users use wordpad, notepad will not handle the carriage returns properly.

################################################

kk2.name=KK2

kk2.upload.protocol=usbasp

kk2.upload.maximum_size=32768

kk2.upload.speed=38400

kk2.build.mcu=atmega324p

kk2.build.f_cpu=20000000L

kk2.build.core=arduino

kk2.build.variant=kk2

################################################

kk21.name=KK2.1

kk21.upload.protocol=usbasp

kk21.upload.maximum_size=65536

kk21.upload.speed=38400

kk21.build.mcu=atmega644pa

kk21.build.f_cpu=20000000L

kk21.build.core=arduino

kk21.build.variant=kk2

################################################

Step 2. Add the KK2 variant.

Find the variant folder.

OSX navigate to.

Arduino.app/Contents/Resources/Java/hardware/arduino/variants/

Windows.

hardware\arduino\variants

Download the pins_arduino.h file from the bottom of this article.

Then create a new folder kk2 and place the pins_arduino.h file inside.

You should have something that looks like this:

The code in pins_arduino.h is where all the magic happens. Basically it maps the pins from the ATMega324 to the more familiar Arduino format.

Step 3. Edit avrdude.conf.

If you are running the KK2.1 you can skip this step.

This step is done because the version of AVRDude that is bundled with Arduino has a bug in its config file, don't worry this is easy to fix.

OSX navigate to:

Arduino.app/Contents/Resources/Java/hardware/tools/avr/etc

or Windows

hardware\tools\avr\etc

and open avrdude.conf with a text editor.

Windows use a code editor, or failing that wordpad. Notepad cannot handle the Unix carriage returns in this file.

Search for ATMega324 to find this part of the document.

We need to change the signature from 0x1e 0x95 0x08 to 0x1e 0x95 0x11.

Save it.

Step 4. Add the LCD library.

Download the KK2LCD library from the bottom of this article. Unzip it.

As long as you have opened Arduino at least once you should have an Arduino directory in your documents folder.

If there is no libraries folder in the Arduino directory create it.

Then put the KK2LCD folder inside that. Alternatively you can unzip the library in the library folder.

It should look something like this:

Step 5. Connect your programmer and KK2.

Easy, like this:

Programming the KK2 with USBASP programmer.

Step 6. Upload the example code to your KK2.

Make sure all the edited documents are saved and closed.

Quit Arduino and then open it again.

Do the following in the Arduino menu:

Tools->Board->KK2

Tools->Programmer->USBasp

finally.

File->Upload Using Programmer

If all went well you should have the example program running on your KK2.

Step 7. Hack away.

Feel free to copy and modify my example code below (it is also included in the KK2LCD library). Remember to always upload using the Upload Using Programmer option as the regular upload button will not work.

Happy hacking.

//Arduino on the KK2 test code by Marc Griffith is licensed under a Creative Commons Attribution 3.0 Unported License.

//http://creativecommons.org/licenses/by/3.0/deed.en_US

//instructions and videos on getting this working with Arduino are available here

//http://www.rchacker.com/diy/arduino-on-the-kk2-multicopter-controller

#include <KK2LCD.h>

//AIL, THR etc

//can also be digital outputs

const byte IN1 = 0; //PD3 (PCINT27/TXD1/INT1) not tested, but use Serial1

const byte IN2 = 1; //PD2 (PCINT26/RXD1/INT0) interrupts good for CCPM decoding.

const byte IN3 = 2; //PD0 (PCINT24/RXD0/T3) tx0 is on the lcd not sure if using this would conflict with the lcd

const byte IN4 = 3; //PB2 (PCINT10/INT2/AIN0)

const byte IN5 = 4; //PB0 (PCINT8/XCK0/T0) //timer/counter0 source

//motor outputs can also be digital inputs. these also have PCINT16 to 23 Arduino interrupts not tested.

const byte OUT1 = 5; //PC6 (TOSC1/PCINT22) //32.768kHz crystal or custom clock source for counter (rpm sensor)

const byte OUT2 = 6; //PC4 (TDO/PCINT20) //JTAG

const byte OUT3 = 7; //PC2 (TCK/PCINT18) //JTAG

const byte OUT4 = 8; //PC3 (TMS/PCINT19) //JTAG

const byte OUT5 = 9; //PC1 (SDA/PCINT17) //I2C i2c not tested

const byte OUT6 = 10; //PC0 (SCL/PCINT16) //I2C

const byte OUT7 = 11; //PC5 (TDI/PCINT21) //JTAG

const byte OUT8 = 12; //PC7 (TOSC2/PCINT23) //32.768kHz crystal

const byte RED_LED = 13; //PB3 (PCINT11/OC0A/AIN1) //same as arduino!

//important enable the internal pullups when using these as inputs

const byte BUT1 = 14; //PB7 (PCINT15/OC3B/SCK) PWM pwm not tested

const byte BUT2 = 15; //PB6 (PCINT14/OC3A/MISO) PWM

const byte BUT3 = 16; //PB5 (PCINT13/ICP3/MOSI)

const byte BUT4 = 17; //PB4 (PCINT12/OC0B/SS)

const byte _BUZZER = 18;  //PB1 (PCINT9/CLKO/T1)   CLOCK output can adjust with system prescaler. (make tones) not tested

//uncomment if you want to write your own LCD library

/*

const byte LCD_CS1 = 19;

const byte LCD_RES = 20;

const byte LCD_A0 = 21;

const byte LCD_SCL = 22;

const byte LCD_SI = 23;

*/

//analog reads must be done using thier channels, specifying digital pin numbers will not work in this case

const byte BATT = 3;

const byte GYR_R = 1;

const byte GYR_Y = 2;

const byte GYR_P = 4;

const byte ACC_X = 5;

const byte ACC_Y = 6;

const byte ACC_Z = 7;

//most of the hardware pwm is on the LCD, LED pins so dont bother. There is PWM on the buttons.

const int switch_release_debounce_us = 100; //milliseconds

const int switch_press_debounce_uS = 500; //microseconds

void setup() {

// put your setup code here, to run once:

pinMode(RED_LED, OUTPUT);

pinMode(GYR_R, INPUT);

pinMode(GYR_Y, INPUT);

pinMode(GYR_P, INPUT);

pinMode(ACC_X, INPUT);

pinMode(ACC_Y, INPUT);

pinMode(ACC_Z, INPUT);

pinMode(BUT1,INPUT);

digitalWrite(BUT1, HIGH); //enable internal pullup.

pinMode(BUT2,INPUT);

digitalWrite(BUT2, HIGH);

pinMode(BUT3,INPUT);

digitalWrite(BUT3, HIGH);

pinMode(BUT4,INPUT);

digitalWrite(BUT4, HIGH);

analogReference(EXTERNAL); //important!!

st7565Init( Font5x7 );

st7565SetBrightness(12);

st7565DrawString_P( 64, 40, PSTR("Arduino on") );

st7565DrawString_P( 64, 32, PSTR(" the KK2.") );

st7565DrawString_P( 64, 24, PSTR("Test suite") );

st7565DrawString_P( 64, 16, PSTR(" v1.0 ") );

st7565DrawString_P( 64, 8, PSTR( " Marc G") );

st7565DrawString_P( 50, 1, PSTR("Press any key") );

st7565WriteLogo(); //see library to modify

delay(1000);

while(true)

{

if(!digitalRead(BUT1)||!digitalRead(BUT2)||!digitalRead(BUT3)||!digitalRead(BUT4)) {

break;

}

String Str = String("hello hello");

char str[7];

int ii = 0;

// every time I write debounce code it comes out different. Complicated but I like the feel of it.

byte button4Pressed()

{

if(!digitalRead(BUT4))

{

delayMicroseconds(switch_press_debounce_uS);

if(!digitalRead(BUT4))

{

while(!digitalRead(BUT4))

{

st7565SetBrightness(12);

st7565ClearBuffer();

st7565SetFont( Font12x16 );

st7565DrawString_P( 42, 26 , PSTR("Next") );

st7565Refresh();

digitalWrite(RED_LED,HIGH);

//we could put a beep in here too.

}

delayMicroseconds(switch_release_debounce_us);

digitalWrite(RED_LED,LOW);

return 1;

}

return 0;

}

void fonts()

{

//delay(200);

// st7565SetBrightness(12);

while(true)

{

st7565ClearBuffer();

st7565SetBrightness(12);

st7565SetFont( Font12x16 );

st7565DrawString_P( 0, 0, PSTR("Font12x16") );

st7565SetFont( Font12x24Numbers );

st7565DrawString_P( 0+40, 15+12, PSTR("12") );

st7565DrawString_P( 34+40, 15+12, PSTR("24") );

st7565SetFont( Font12x16 );

st7565DrawChar( 24+40, 20+12, (uint8_t) '.' );

st7565SetFont( Font5x7 );

st7565DrawString_P( 20, 14, PSTR("Font5x7") );

st7565DrawString_P( 102, 54, PSTR("Next") );

st7565Refresh();

if(button4Pressed())

return;

}

/*

// needs fixing, causes memory leaks !!

void drawCoordinates(int x, int y)

{

Str = String(x) + "," + String(y);

Str.toCharArray(str,6);

st7565DrawString( x, y, str);

}

void text_position()

{

delay(200);

st7565SetBrightness(12);

while(true)

{

st7565ClearBuffer();

st7565SetBrightness(12);

st7565SetFont( Font5x7 );

st7565DrawString_P( 0, 8, PSTR("Co-ords test") );

drawCoordinates(0,0);

drawCoordinates(80,0);

drawCoordinates(81,8);

drawCoordinates(82,16);

drawCoordinates(83,24);

drawCoordinates(84,32);

drawCoordinates(85,40);

drawCoordinates(86,48);

drawCoordinates(0,20);

drawCoordinates(6,28);

drawCoordinates(0,56);

drawCoordinates(38,56);

st7565DrawString_P( 102, 56, PSTR("Next") );

st7565Refresh();

if(button4Pressed())

return;

}

}*/

void analog()

{

int aread = 0;

// delay(switch_release_debounce);

st7565SetBrightness(12);

while(true)

{

st7565ClearBuffer();

st7565SetBrightness(12);

st7565SetFont( Font12x16 );

st7565DrawString_P( 0, 0, PSTR("Analog Read") );

st7565SetFont( Font5x7 );

delayMicroseconds(10);

aread = analogRead(GYR_R);

Str = String(aread);

Str.toCharArray(str,6);

st7565DrawString_P(10*6,16,PSTR("GYR_R "));

st7565DrawString(16*6,16,str);

delayMicroseconds(10);

aread = analogRead(GYR_Y);

Str = String(aread);

Str.toCharArray(str,6);

st7565DrawString_P(10*6,24,PSTR("GYR_Y "));

st7565DrawString(16*6,24,str);

delayMicroseconds(10);

aread = analogRead(GYR_P);

Str = String(aread);

Str.toCharArray(str,6);

st7565DrawString_P(10*6,32,PSTR("GYR_P "));

st7565DrawString(16*6,32,str);

delayMicroseconds(10);

aread = analogRead(ACC_X);

Str = String(aread);

Str.toCharArray(str,6);

st7565DrawString_P(0,16,PSTR("ACC_X "));

st7565DrawString(6*6,16,str);

delayMicroseconds(10);

aread = analogRead(ACC_Y);

Str = String(aread);

Str.toCharArray(str,6);

st7565DrawString_P(0,24,PSTR("ACC_Y "));

st7565DrawString(6*6,24,str);

delayMicroseconds(10);

aread = analogRead(ACC_Z);

Str = String(aread);

Str.toCharArray(str,6);

st7565DrawString_P(0,32,PSTR("ACC_Z "));

st7565DrawString(6*6,32,str);

delayMicroseconds(10);

aread = analogRead(BATT);

Str = String(aread);

Str.toCharArray(str,6);

st7565DrawString_P(0,48,PSTR("BATT "));

st7565DrawString(6*6,48,str);

st7565DrawString_P( 102, 56, PSTR("Next") );

st7565Refresh();

if(button4Pressed())

return;

}

void buttons()

{

st7565SetBrightness(12);

// delay(switch_release_debounce);

while(true)

{

st7565ClearBuffer();

st7565SetFont( Font12x16 );

st7565DrawString_P( 0, 0, PSTR(" Buttons") );

st7565SetFont( Font12x24Numbers );

Str = String(digitalRead(BUT1));

Str.toCharArray(str,5);

st7565DrawString( 0, 38, str);

Str = String(digitalRead(BUT2));

Str.toCharArray(str,5);

st7565DrawString( 38, 38, str);

Str = String(digitalRead(BUT3));

Str.toCharArray(str,5);

st7565DrawString( 76, 38, str);

st7565SetFont( Font5x7 );

st7565DrawString_P( 102, 56, PSTR("Next") );

st7565Refresh();

if(button4Pressed())

return;

}

void leds()

{

// delay(switch_release_debounce);

st7565SetBrightness(12);

while(true)

{

byte offset = 0;

for (int i = 0;i<14 ;i++)

{

st7565ClearBuffer();

st7565SetFont( Font12x16 );

st7565DrawString_P( 0, 0, PSTR("Digital out") );

Str = String(i);

Str.toCharArray(str,5);

st7565SetFont( Font5x7 );

st7565DrawString_P(0,28,PSTR("digitalWrite("));

st7565DrawString(13*6,28,str);

if(i>9)

{

offset = 6;

}

st7565DrawString_P(14*6+offset,28,PSTR(",HIGH)"));

st7565DrawString_P(20*6-2+offset,28,PSTR(";"));

st7565DrawString_P( 102, 56, PSTR("Next") );

/*

st7565SetFont( Font12x24Numbers );

st7565DrawString( 0+OFFSET_X, 15+OFFSET_Y, str);

*/

pinMode(i,OUTPUT);

digitalWrite(i,HIGH);

st7565Refresh();

for(int k = 0;k<100;k++)

{

if(button4Pressed())

return;

delay(5);

}

digitalWrite(i,LOW);

pinMode(i,INPUT);

}

void contrast()

{

while(true)

{

for (int i = 0;i<35;i++)

{

st7565ClearBuffer();

st7565SetFont( Font12x16 );

st7565DrawString_P( 0, 0, PSTR("SetBrightness()") );

Str = String(i);

Str.toCharArray(str,5);

st7565SetFont( Font12x24Numbers );

st7565DrawString( 50, 20, str);

st7565SetBrightness(i);

st7565SetFont( Font5x7 );

st7565DrawString_P( 102, 56, PSTR("Next") );

st7565Refresh();

//gives us a delay of 250ms while still detecting button presses

for(int k = 0;k<50;k++)

{

if(button4Pressed())

return;

delay(5);

}

void time()

{

unsigned long time = 0;

st7565SetBrightness(12);

st7565ClearBuffer();

st7565SetFont( Font12x16 );

st7565DrawString_P( 0, 0, PSTR("Test clock") );

st7565SetFont( Font5x7 );

st7565DrawString_P( 4, 24, PSTR("One flash per second.") );

st7565DrawString_P( 102, 56, PSTR("Next") );

st7565Refresh();

while(true)

{

// heartbeat

if (millis() % 1000)

{

digitalWrite(RED_LED,LOW);

}

else

{

digitalWrite(RED_LED,HIGH);

delay(100);

}

if(button4Pressed())

return;

}

void loop() {

analog();

buttons();

leds();

fonts();

contrast();

time();

//text_position()

}

///////////////////////////////////////////////////other disorganised stuff..

error compiling

unknown MCU 'atmega324pa' specified

reason.

http://arduino.cc/forum/index.php?topic=49264.0

http://www.forums.adafruit.com/viewtopic.php?f=25&t=13164

solution. edit avrdude.conf. This is ugly but it works.

Arduino.app/Contents/Resources/Java/hardware/tools/avr/etc

dont program it with it on your lap!

reset the fuses

http://www.rcgroups.com/forums/showpost.php?p=23393086&postcount=7653

avrdude -c usbasp -p m324pa -U lfuse:w:0xf7:m -U hfuse:w:0xd7:m -U efuse:w:0xfc:m -F

avrdude -p m324pa -U lfuse:w:0xe2:m -U hfuse:w:0xd7:m -U efuse:w:0xfc:m -F

Graphics!. A delve into the openAero code and some that KaptienKuk posted has helped get this working.

installing LCD Assistant.

windows, no installation needed, just run it.

MacOSX, macports, wine, and run with wine.

Important, Arduino code use external analog reference. otherwise when you try to do an analog read it will short out and reset, lucky no damage. This took a while to figure out but the details are buried in the datasheet.

None of the output pins have PWM, so KaptienKuk does it all in software. The PWM pins seem to be wasted on the buttons and LCD interface. There are 8 PWM pins available, not sure why KK did not use them all for the outputs. Must be a good reason.

UPDATE. Correction, there are 6 PWM pins available (thanks to Ciskje from Italy). I can see now the reason.

Other comms methods are available which means opportunities for expansion. Perhaps KK has a GPS, Magnetometer or Baro add on in mind?

Serial connections exposed, RX0, TX1 and RX1. TX0 is used on the LCD interface. But Serial1 can be used to talk to a computer via an FTDI chip for example.
I2C is available on the output headers.
SPI can be used as a master but the Slave Select pin is on one of the buttons.