This page describes how to assemble the Ardumower PCB, flash the Arduino and configure the robot mower.

Inhaltsverzeichnis

1 Abstract
2 Needed modules
3 PCB
4 Power supply
5 Download and flash Arduino code
6 Settings
7 First-time usage
8 Starting the mower
9 Diagnostics/troubleshooting
- 9.1 Error codes and troubleshooting
10 Error counter / error beeps
- 10.1 I2C bus / error beeps
11 Further links

Abstract

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

Components overview
Ardumower PCB connects all modules (available in the shop)
PCB top
PCB back
PCB and MC33926

Needed modules

All modules can be purchased as complete kits via the shop .

PCB

The printed circuit board (PCB) connects all electronic modules. The PCB is made with the following design parameters:

PCB dimensions 241x114mm
All modules (motor driver, Bluetooth, etc.) can be soldered (or plugged) on the PCB (modules are available in the Ardumower shop)
Uses the Arduino Mega 2560
Optional: can use Arduino Due via additional adapter PCB
Optional: integrated charging circuit (current limiting)
All connections are available on connectors as well as +5V and GND
Max. trace current (for motors): 8A

PCB building manual

Robot PCB v0.5 (initial prototype, please do not use anymore)

Robot PCB v1.2 (minor layout changes)

Schematics
Photos
Build instructions
Build instructions (English translation)
WorkaRound20150527
WorkaRound20150530
also see: Documentation in Github

NOTE: The schematics and PCB files were created with KiCad. They can be downloaded from github and can be edited by open source KiCAD software (Download here or here).

PCB building videos

PCB jumpers

Feature used	YES	NO	Comment
Integrated charging control via adjustable voltage regulator (LM350T) with potentiometer for adjustable charging voltage (recommended: NO)	D7: DIODE D3: DIODE C1, C4, U4, RV1: used	D7: SHORT-CIRCUIT D3: SHORT-CIRCUIT C1, C4, U4, RV1: not used	Do not use if using external battery charger
External power while charging (recommended: NO)	JP6: CLOSE JP7: OPEN D4: DIODE C5: not used	JP6: OPEN JP7: CLOSE D4: SHORT-CIRCUIT C5: used	Use to power your PCB from externally (disconnect battery from PCB) while charging
Arduino controlled charge relay (recommended: YES)	JP4: CLOSE JP5: OPEN	JP4: OPEN JP5: CLOSE	Use for Arduino controlled charge relay (not automatic charging)
Arduino Due (3.3V I/O)	LP0, ..., LP15: OPEN	LP0, ..., LP15: CLOSE	Do not use if using Arduino Mega
Bluetooth VCC=3.3V	JP8: OPEN JP9: CLOSE	JP8: CLOSE JP9: OPEN	Many latest modules use 3.3V
Bluetooth programming mode	JP2: CLOSE	JP2: OPEN	Use for reprogramming baud rate etc.

PCB modules

Note for Marotronics INA169: Short pads for 5A operation

Module	Feature	Pinout	Optional	Comment
U1	DC/DC converter (10V)	GND, Vout, Vin, GND	No
U2	Bluetooth (HC-05)	VCC, GND, TXD, RXD, Key, LED	Yes
U3	Current sensor (charging)	VCC, GND, OUT, IP+, IP-5	Yes
U4	Charge control (LM350T)	AJD, OUT, IN	Yes
U5	Current sensor (charging)	VCC, GND, OUT, IP+, IP-5	Yes
U6	DC/DC converter (3.3V)	GND, Vout, Vin, GND	No
U7	DC/DC converter (5V)	GND, Vout, Vin, GND	No
U8	Realtime clock (DS1307)	Batt, GND, VCC, SDA, SCL, DS, SQ	Yes
U9	Wifi (ESP8266)	TX, CH_PD, Reset, VCC, GND, GP_IO2, GP_IO0, RX	Yes
U10	Level shifter 5V->3V (Arduino Due)		Yes
U11	Wifi (ESP8266)	TX, CH_PD, Reset, VCC, GND, GP_IO2, GP_IO0, RX	Yes	alternative mount position

PCB connectors

Connector	Feature	Pinout	Optional	Comment
P1	Sonar center (HC SR-04)	5V, GND, Trigger, Echo	Yes
P2	Sonar right (HC SR-04)	5V, GND, Trigger, Echo	Yes
P3	Sonar left (HC SR-04)	5V, GND, Trigger, Echo	Yes
P4	reserved		Yes
P5	IMU (gyro,acceleration,compass) (GY-80)		Yes
P6	Lawn sensor		Yes
P7	Status LEDs		Yes
P8	Odometry right		Yes
P9	Odometry left		Yes
P10	GPS (GY-NEO6MV2)		Yes
P11	Bumper	GND, GND, right, left	Yes
P12	Perimeter coil (center or left)	5V, GND, perimeter	Yes
P13	R/C remote control	5V, GND, mow, steer, speed, switch	Yes
P14	Measurement points	5V, GND, (Depending on JP15: 3.3V, 5V or Arduino 3.3V)	Yes
P15	Wheel motor left	M1OUT1, M1OUT2	No
P16	Optional motor driver input		Yes	Do not connect
P17	Optional motor driver input		Yes	Do not connect
P18	Wheel motor right	M2OUT1, M2OUT2	No
P19	Tilt sensor	5V, GND, tilt	Yes
P20	Button (Start/Stop)		No
P21	Drop sensor right		Yes
P22	Reserved		Yes
P23	Reserved		Yes
P24	Reserved		Yes
P25	Reserved		Yes
P26	Reserved		Yes
P27	Reserved		Yes
P28	Reserved		Yes
P29	Reserved		Yes
P30	Perimeter coil right		Yes
P31	Drop sensor left		Yes
P32	GND		Yes
P33	5V		Yes
P34	3.3V		Yes
P35	Mower motor RPM		Yes
P36	Reserved		Yes
P37	Mower motor		No
P38	Reserved		Yes
P39	Reserved		Yes
P40	User switches		Yes
P41	Rain sensor		Yes
P42	Charging pins		Yes
P43	Battery (24V)		No
P44	Wifi module (ESP8266)		Yes
P45	Reserved		Yes
P46	Reserved		Yes

Power supply

Please also read the section 'Voltages' under Motor driver for more information on motor voltages.

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.

Download and flash Arduino code

NOTE: If you have never worked with Arduino before, read our 'Arduino first steps' introduction.

You have two options:

Download github code (recommended) OR
Download v0.9.3 code (old, not recommended)

Finally, download and start the Arduino IDE to flash the code to your Arduino.

Arduino Version: It is very Importent that you use the Arduino IDE version 1.6.3 or above AND select the right Board (Mega 2560 or Due).

Important for Arduino IDE 1.6 or higher: if you see any folders inside the code folder (e.g. 'unused'), please delete them before compilation! Note: Always verify that the pin configuration in your Arduino code (config.h/mower.cpp) matches your actual circuit!

Settings

The robot uses settings that you can adjust for your own robot and environment (via pfodApp or directly in the code). The default settings (factory settings) are stored in the config file 'mower.cpp'. In this file you can find a description of all settings.

The settings can be adjusted via Android phone (pfodApp).

Visualization of settings
Motor speed settings

Important: If you uploaded a new version into your robot, reset all settings via pfodApp once (Settings->Factory reset). This will delete all existing settings. Old settings can produce malfunction if the internal settings format has changed.

First-time usage

1. At first, deactivate all sensors - In 'mower.cpp' set the robot settings like this:

bumperUse = 0;
dropUse = 0;
rainUse = 0;
sonarUse = 0;
perimeterUse = 0;
lawnSensorUse = 0;
imuUse = 0;
batMonitor = 0;
odometryUse = 0;
gpsUse = 0;
buttonUse = 1;
timerUse = 0;

2. The software offers a serial console 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. First let's delete any existing error. Send the letter 'd' to the Arduino.

Console:
press...
d for menu
e=delete all errors

3. Run the ADC calibration, so that the ADC signals are symmetric around zero.

pres...
8=ADC calib (perimeter sender, charger must be off)

4. Save user settings

press...
9=saver user settings

5. Test motors:

press...
1=test motors

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

You should verify that the wheel motors are controlled correctly and in the right direction. Increase 'motorAccel' in 'mega.cpp' if the motors are not accelerating quickly enough.

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

Diagnostics/troubleshooting

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:

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

Using the key 'v', you can toggle between sensor trigger counters and current sensor values.

Additionally, you can use pfodApp (Android) to plot the sensors (trigger counters and current values) over time. This allows you to wirelessly monitor your robot mower for error diagnostics. It is highly recommended.

Sensor trigger counters
Sensor measurement values
Ardumower states

Error codes and troubleshooting

http://wiki.ardumower.de/index.php?title=Troubleshooting

Error counter / error beeps

If there's a communication problem or another serious problem, the error counter increases. The error counter can be monitored via pfodApp. Additionally, the robot mower will beep when started.

See section Troubleshooting for details on all errors.

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.

Ardumower PCB