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arduinomega

The controller is built around a ready microcontroller board (Arduino Mega 2560 using 54 I/O pins).

Required parts

ardumower parts    ardumower overview

  • Main functions
    • Arduino cable (female-female and male-female jumper cable)
    • 1 x Arduino Mega 2560
    • 1 x DC voltage step-down module (LM2596)
    • 2 x L298N motor driver module
    • 3 x current sensor module ACS712-5
    • 1 x current sensor module ACS712-30
    • 1 x mower motor driver circuit: MOSFET IRLIZ44N, Diode MBR1045, Schottky-Diode 10A, Resistors (10K, 180 Ohm)
    • Resistors (2 x 47K, 2 x 5K), Capacitors ( Fuse F20A250V
    • Piezo buzzer (0,1W), button, ON/OFF switch 10A
  • Perimeter sender (optional)
    • 1 x Arduino Nano
    • Coil 220µH, Elko 2,2µF/160V, Resistors (1 Ohm, 1K, 4,7K), Diode 1N4448
    • 1 x DC voltage step-down module (LM2596)
    • 1 x L298N motor driver module
  • Perimeter receiver (optional)
    • 1 x Arduino Nano
    • 2 x Arduino Sound Sensor Module (must use LM386)
    • Capacitors (2 x 4,7nF, 2 x 100nF), Resistors (2 x 200k), 2 x Receiver coils 85mH
  • Additional module
    • 1 x HC-SR04 ultrasonic sensor module (optional)
    • 1 x GY80 module (gyro, accel. compass) (optional)
    • 1 x DS1307 realtime clock module (optional)
    • 1 x Bluetooth module (for phone control)
  • Here you can find all components: robot4

 

Schematics

ardumower schematics


Power supply

It is recommended to use a voltage step-down converter (e.g. module using LM2596) to generate the 5V voltage for the Arduino and all additional modules. Before connecting, set the voltage of the converter to 5V. Warning : never connect more than 5V on the Arduino 5V pins, or you will damage the Arduino. Therefore, always measure the 5V voltage before connecting it to the Arduino 5V pin!
All components together (as shown in the schematics) need about 5W power.

I2C bus / error beeps
Several components (Arduino Nano, RTC, IMU, etc.) are communicating via the I2C bus (SDA/SCL wires). These wires should be very short (maybe even twisted) and they should be far away from DC converter and motor drivers. If there's a communication problem, the error counter will increase and robot will beep when started. The error counter can be monitored via pfodApp.

First-time using

warning
Security note: For security reasons, always remove mower blades in your first tests!

Initially, you should verify that the wheel motors are controlled correctly and in the right direction. The software offers a diagnostic mode. Open the serial console in the Arduino IDE (CTRL+SHIFT+M) and set the baudrate to 19200. The motor and sensor values should appear constantly:

    20 OFF  spd    0    0    0 sen    0    0    0 bum    0    0 son...
    21 OFF  spd    0    0    0 sen    0    0    0 bum    0    0 son...
    22 OFF  spd    0    0    0 sen    0    0    0 bum    0    0 son...
    23 OFF  spd    0    0    0 sen    0    0    0 bum    0    0 son...
    24 OFF  spd    0    0    0 sen    0    0    0 bum    0    0 son...
    ...

Now, press the key ‘t’ on the keyboard, and confirm using ENTER. The diagnostic mode should appear, and you can test your motors.

Diagnostic

Each time a sensor triggers, its corresponding sensor counter increases. The sensor trigger counters as well as the current sensor values can be viewed on the serial console. The following values are shown for the trigger counters in the serial console:

1) Time of state machine's state (ms)
2) loop()-counts per second
3) choosen Verbose-Mode (0=counter readings/1=current values/2=current values)
4) current state machine state (FORW, REV, ROLL etc.)
5) drive home? (1/0)
6) "spd" - Control/speed motors: left (PWM), right (PWM), mower (RPM)
7) "sen" - Current limit exceeded counter motors: left, right, mower 
8) "bum" - bumper counter: left, right 9) "son" - Ultrasonic-distance threshold exceeded (counter) 10) "pit/roll" - Tilt (computed by acceleration sensor) 11) "com" - compass course 12) "per" - Perimeter loop detected: counter 13) "bat" - Battery voltage 14) "chg" - Charging current

Using the key 'v', you can toggle between summary of sensor (counters) and current sensor values.

Additionally, you can use pfodApp (Android) to plot the sensors (trigger counters and current values) over time:

ardumower sensor counter plotting    ardumower plot sensors



Starting the mower

To start the mower, you need to add a button and a buzzer:

pinButton —o Button o— GND (button for ON/OFF)

pinBuzzer —o Buzzer o— GND (Piezo buzzer)

Now, press the button as long as you hear the beeps:

Mode (press button for x beeps):
1 beeps : Normal mowing (using blade modulation if available)
2 beeps : Normal mowing (without blade modulation)
3 beeps : Drive by model remote control (RC)
4 beeps : Drive without mowing
5 beeps : Find perimeter and track it

Error counter / error beeps
If there's a communication problem (see I2C section further above), the error counter increases. The error counter can be monitored via pfodApp. Additionally, the robot mower will beep when started.

Demo Videos
video  Ambrogio Ardumower: First operation (Highlights)

video  Rotenbach Ardumower: First operation

Arduino-Code
See section 'Downloads'
IMPORTANT! You need to use Arduino IDE v1.5.6 or higher!


New to Arduino?
Have a look at the folllowing (external) videos and pages to learn more about Arduino:

  1. http://www.youtube.com/playlist?list=PLT6rF_I5kknPf2qlVFlvH47qHvqvzkknd


Basic principles of the software

The following will describe some basic principles of the software:

Config files
Config files translate the commands of the main program into the specific hardware (i.e. actuators and sensors) - that allows us to adapt the main program to different robot mowers:

ardumower config files

Example:

The main program wants to drive the left wheel motor by the value 100. The chosen robot config file is called by the main program with this command: 
setActuator(ACT_MOTOR_LEFT, 100)

The chosen config file will then execute this command by calling the specific motor driver:
setL298N(pinMotorLeft, pinMotorLeftPWM, 100)


Adjusting the robot mower configuration / pfodApp menu structure
Instructions for adjusting the robot mower configuration as well as the menu structure can be found here:
http://www.ardumower.de/index.php/de/steuerung-software-schaltbild-teile
 

Finate state machine
Main component of the software is a so called 'finate state machine', that means there exists a set of states ("OFF", "FORWARD", "ROLL", etc.) that the robot can be in. Depending on events (sensor is triggering etc.), the robot will enter a new state.

State diagram

ardumower statemachine

 



 

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