How to Build an Arduino Based Controller Systems

Arduino Uno board

If you want to build your own control system, you can review some options at Control Systems. The option described here, to build your own controller device, is that you could leverage an Arduino device. For that option, first lets cover some background on the approach, and then the steps to take to build this controller.

Unlike smartphones or PCs, Arduino boards (and other prototype development boards) have digital output options built into them. Typically the large number of digital output options makes it easier for them to control a variety of external actuators. If you want to use data ports to control items like an LED light or an electric motor, you won't need additional electronics for any handshake. However, you shouldn't wire up a digital output directly to a motor since a motor will probably draw more current than the digital output is rated for.

That said, these built in digital output options aren't always mapped to I/O addresses or memory addresses the same in every board or even chip. For example, the table below shows the I/O addresses for the AVR ATmega328 (typically used in the Arduino Uno board) and the radiation tolerant AVR ATmegaS128. Because of these differences in digital I/O locations, programmers are encouraged to use macros, functions, or procedures in the high level programming languages that will map I/O operations to the appropriate address for the chip being used.

Arduino / AVR port pins

ATmega328 IO Address	ATmega328 Memory Address	ATmega128 IO Address	ATmega128 Memory Address	Signal Name	Direction
0x05	0x25	0x18	0x38	PORTB0	Out Data
0x05	0x25	0x18	0x38	PORTB1	Out Data
0x05	0x25	0x18	0x38	PORTB2	Out Data
0x05	0x25	0x18	0x38	PORTB3	Out Data
0x05	0x25	0x18	0x38	PORTB4	Out Data
0x05	0x25	0x18	0x38	PORTB5	Out Data
0x05	0x25	0x18	0x38	PORTB6/XTAL1/TOSC1	Out Data
0x05	0x25	0x18	0x38	PORTB7/XTAL2/TOSC2	Out Data
0x04	0x24	0x17	0x37	DDB0	IO Control
0x04	0x24	0x17	0x37	DDB1	IO Control
0x04	0x24	0x17	0x37	DDB2	IO Control
0x04	0x24	0x17	0x37	DDB3	IO Control
0x04	0x24	0x17	0x37	DDB4	IO Control
0x04	0x24	0x17	0x37	DDB5	IO Control
0x04	0x24	0x17	0x37	DDB6/XTAL1/TOSC1	IO Control
0x04	0x24	0x17	0x37	DDB7/XTAL2/TOSC2	IO Control
0x03	0x23	0x16	0x36	PINB0	In Data
0x03	0x23	0x16	0x36	PINB1	In Data
0x03	0x23	0x16	0x36	PINB2	In Data
0x03	0x23	0x16	0x36	PINB3	In Data
0x03	0x23	0x16	0x36	PINB4	In Data
0x03	0x23	0x16	0x36	PINB5	In Data
0x03	0x23	0x16	0x36	PINB6/XTAL1/TOSC1	In Data
0x03	0x23	0x16	0x36	PINB7/XTAL2/TOSC2	In Data
0x08	0x28	0x15	0x35	PORTC0/ADC0	Out Data
0x08	0x28	0x15	0x35	PORTC1/ADC1	Out Data
0x08	0x28	0x15	0x35	PORTC2/ADC2	Out Data
0x08	0x28	0x15	0x35	PORTC3/ADC3	Out Data
0x08	0x28	0x15	0x35	PORTC4/ADC4	Out Data
0x08	0x28	0x15	0x35	PORTC5/ADC5	Out Data
0x08	0x28	0x15	0x35	PORTC6	Out Data
0x08	0x28	0x15	0x35	PORTC7	Out Data
0x07	0x27	0x14	0x34	DDC0/ADC0	IO Control
0x07	0x27	0x14	0x34	DDC1/ADC1	IO Control
0x07	0x27	0x14	0x34	DDC2/ADC2	IO Control
0x07	0x27	0x14	0x34	DDC3/ADC3	IO Control
0x07	0x27	0x14	0x34	DDC4/SDA/ADC4	IO Control
0x07	0x27	0x14	0x34	DDC5/SCL/ADC5	IO Control
0x07	0x27	0x14	0x34	DDC6	IO Control
0x07	0x27	0x14	0x34	DDC7	IO Control
0x06	0x26	0x13	0x33	PINC0/ADC0	In Data
0x06	0x26	0x13	0x33	PINC1/ADC1	In Data
0x06	0x26	0x13	0x33	PINC2/ADC2	In Data
0x06	0x26	0x13	0x33	PINC3/ADC3	In Data
0x06	0x26	0x13	0x33	PINC4/SDA/ADC4	In Data
0x06	0x26	0x13	0x33	PINC5/SCL/ADC5	In Data
0x06	0x26	0x13	0x33	PINC6	In Data
0x06	0x26	0x13	0x33	PINC7	In Data
0x0B	0x2B	0x12	0x32	PORTD0/RXD	Out Data
0x0B	0x2B	0x12	0x32	PORTD1/TXD	Out Data
0x0B	0x2B	0x12	0x32	PORTD2	Out Data
0x0B	0x2B	0x12	0x32	PORTD3	Out Data
0x0B	0x2B	0x12	0x32	PORTD4	Out Data
0x0B	0x2B	0x12	0x32	PORTD5	Out Data
0x0B	0x2B	0x12	0x32	PORTD6	Out Data
0x0B	0x2B	0x12	0x32	PORTD7	Out Data
0x0A	0x2A	0x11	0x31	DDD0/RXD	IO Control
0x0A	0x2A	0x11	0x31	DDD1/TXD	IO Control
0x0A	0x2A	0x11	0x31	DDD2	IO Control
0x0A	0x2A	0x11	0x31	DDD3	IO Control
0x0A	0x2A	0x11	0x31	DDD4	IO Control
0x0A	0x2A	0x11	0x31	DDD5	IO Control
0x0A	0x2A	0x11	0x31	DDD6	IO Control
0x0A	0x2A	0x11	0x31	DDD7	IO Control
0x09	0x29	0x10	0x30	PIND0/RXD	In Data
0x09	0x29	0x10	0x30	PIND1/TXD	In Data
0x09	0x29	0x10	0x30	PIND2	In Data
0x09	0x29	0x10	0x30	PIND3	In Data
0x09	0x29	0x10	0x30	PIND4	In Data
0x09	0x29	0x10	0x30	PIND5	In Data
0x09	0x29	0x10	0x30	PIND6	In Data
0x09	0x29	0x10	0x30	PIND7	In Data

How To:

1) collect items you will need

• Arduino
• components for simple Motor circuit
• 1 transistor - ex: 100 x 2N2222 NPN TO-92 Plastic-Encapsulate Power Transistors 75V 600mA
• 1 diode - ex: rectifier diode assorted kit,100pcs 1N4148 1N4007 1N5819 1N5399 1N5408 1N5822 FR107 FR207 electronic components package
• 1 capacitor
• 1 100 ohm up to 220 ohm resister
• 1 3V electric motor - ex: 10pcs Micro 130 DC Motor, DC 3-6V 16500 RPM Cars Toys Electric Motor
• solderless breadboard, or wirewrap breadboard, or solder and soldering iron - ex: Solderless Breadboard, 400-Points and 830-Points, 2 Pieces

2) Build the simple Motor circuit and wire up a motor or light

You typically shouldn't wire up a digital output directly to a motor since a motor will probably draw more current than the digital output is rated for. Instead you should have a small amplifying switch circuit, and a separate power supply to drive the motor. This can be done with a transistor circuit to amplify any of the digital output signals from Arduino ports. A diode and capaciter in parallel to the motor prevents problems with the circuit when the motor is stopped and it momentarily acts as a little generator. This circuit can be used for driving a small motor from just about any digital output like a smartphone parallel port, PC parallel port, etc., not just this project. Here's a diagram of the circuit you want to wire up.

3) use an Ardunio sketch to control the Arduino ports

Every time a byte or bit is written to the data ports, the data will be latched (saved), and will remain present until something new is written. Thus you just need to set a bit high to turn on a device, wait while you want the device on, and then set the bit low to turn the device off.

To do this, write a program that sets the bits you want to turn on in a byte or char variable, and send that byte to the digital port, and call a wait routine. Once the wait routine is done, clear the bits and write them to the digital port. The data will be held as long as the program is in the wait routine.

Advanced: 4) Build a bi-directional Motor circuit and wire up a motor with an L293 / SN754410 half H-bridge driver

You can't wire up a digital output directly to a motor and be able to control the motor in three different states: stopped, forward, reverse. Instead you will need two digital outputs, one to control direction and one to turn the motor on and off. You then need a circuit called an H-bridge in order to be able to switch the current direction to the motor. This could be built from scratch with transistors, but it's such a popular circuit you can get ICs that have H-bridge or half H-bridge circuits. The L298 is a popular dual packaged full H-bridge IC, while the L293 (aka SN754410) is a popular quadruple package half H-bridge IC. You can use two half H-bridge circuits with a little other circuitry to form the equivalent of a full H-bridge so these two ICs offer similar capabilities. For this example we use an L293 since it's easier to put this chip into a solderless breadboard. By using a digital inverter such as a 74LS04, we can tie two half H-bridges driver inputs together so that one always has the opposite state as the other. Here's a diagram of the circuit you want to wire up.

Note that in an h-bridge circuit there is a separate voltage supply for the motors vs. for the digital logic, similar to the simple motor circuit described above. With an Arduino, the digital logic voltage can be provided by the Arduino board. The motor voltage can be supplied independently and can be different than the 5V supplied for the digital logic.

Also note that with this circuit you will not need the simple motor circuit described above.

Now you need to write a program that sets both a direction bit and a bit to turn on or off the motor, and call a wait routine. The data will be held indefinately, but the program will not advance as long as the it is in the wait routine. Once the wait routine is done, clear the bits and write them to the digital port to turn the motors off before turning them on in a different direction. Here's an example of the Arduino Sketch C code that, with the above circuit, can be used to drive a rover with tank drive. It should be able to drive the rover forward, then reverse, and then turn before repeating.

  int motorPin4 = 4;
  int motorPin5 = 5;
  int motorPin6 = 6;
  int motorPin7 = 7;
 
  // stopped
  extern void stop()
  {
    digitalWrite(motorPin4, LOW);
    digitalWrite(motorPin5, LOW);
    digitalWrite(motorPin6, LOW);
    digitalWrite(motorPin7, LOW);
    delay(1000);
  }
 
  extern void setup()
  {
    pinMode(motorPin4, OUTPUT);
    pinMode(motorPin5, OUTPUT);
    pinMode(motorPin6, OUTPUT);
    pinMode(motorPin7, OUTPUT);
 
    stop();
  }
 
  // forward
  extern void forward()
  {
    digitalWrite(motorPin4, HIGH);
    digitalWrite(motorPin5, HIGH);
    digitalWrite(motorPin6, HIGH);
    digitalWrite(motorPin7, HIGH);
    delay(5000);
  }
 
  // reverse
  extern void reverse()
  {
    digitalWrite(motorPin4, HIGH);
    digitalWrite(motorPin5, LOW);
    digitalWrite(motorPin6, HIGH);
    digitalWrite(motorPin7, LOW);
    delay(5000);
  }
 
  // forward on one side and reverse on the other
  // results in turning
  extern void turn()
  {
    digitalWrite(motorPin4, HIGH);
    digitalWrite(motorPin5, HIGH);
    digitalWrite(motorPin6, HIGH);
    digitalWrite(motorPin7, LOW);
    delay(5000);
  }
 
  extern void loop()
  {
    forward();
    stop();
    reverse();
    stop();
    turn();
    stop();
  }

Here's a video of a Arduino (AVR) controlled Snap Rover robot using this h-bridge circuit and this code.

Here's links to tools that are needed or might be helpful when programming an AVR chip on an Arduino board:

• Link to Arduino IDE (C++ compiler) - AVR
• Link to VisualINO - AVR
• Debug AVR - Simulated Debug CPU - AVR ATmega328

teraKUHN solutions

Hardware Setup	Control System	Hardware Abstraction	Development Tools
Smartphone Controller (with PWM or advanced latch circuit)	USB-Controller	teraKUHN IO System (KIOS)	Debug Z80 KCC80 KPC80
Smartphone Controller (with advanced latch circuit)	AVR-Controller	C & C++ coding abstraction macros	Debug AVR Arduino C++
Arduino Controller .	N/A	C & C++ coding abstraction macros	Debug AVR Arduino C++

Here are some architecture characteristics that can be demonstrated by these two control solutions. These differences can be used for teaching processor and microcontroller concepts.

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