Ardumower PCB

2015-07-25T14:12:31Z

Tapsa: /* ADC calibration */

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

The controller is built around a ready microcontroller board (Arduino Mega 2560 using 54 I/O pins).
<gallery>
File: Ardumower_overview.png | Components overview
File: Ardumower_chassis_components.png | Chassis components
File: Arduinomega.jpg | Ardumower's heart: Arduino Mega 2560 microcontroller
File: Ardumower_parts.jpg| Modules available in the shop
File: Ardumower_pcb_photo.jpg | Ardumower PCB connects all modules (available in the shop)
File: Ardumower_chassis_pcb1.jpg | Chassis and PCB inside
File: Ardumower_chassis_pcb2.jpg | PCB mount
</gallery>

=Needed modules=

All modules can be purchased as complete kits via the [https://www.marotronics.de/index.php?k=7 shop] [[File: shopping.png|link=https://www.marotronics.de/index.php?k=7]] .

* Main functions
** Arduino cable (female-female and male-female jumper cable)
** Arduino Mega 2560 (or Arduino Due)
** Adjustable DC voltage step-down modules (3.3v, 5v, 8v)
** dual motor driver module with integrated current sensor (2 wheel motors)
** current sensor module
** motor driver module with integrated current sensor (mower motor)
** Resistors, Capacitors, Fuse
** Piezo buzzer, button, ON/OFF switch

* Perimeter sender (optional)
** Arduino Nano
** DC voltage step-down module
** motor driver module with integrated current sensor

* Perimeter receiver (optional)
** pre-amplifier module
** Capacitor, Receiver coil

* Additional modules
** IMU module (gyro, accel. compass) (REQUIRED)
** realtime clock module (REQUIRED)
** Bluetooth module (for phone control, RECOMMENDED)
** ultrasonic sensor module (optional)

=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 versions=
Robot PCB v0.5 (initial prototype)
* [https://github.com/Ardumower/ardumower/tree/master/pcb/megashield_svn_0.5/Platinenbilder Photos]
* [https://github.com/Ardumower/ardumower/raw/master/pcb/megashield_svn_0.5/ardumower%20mega%20shield%20svn.pdf Schematics]
* [http://www.ardumower.de/media/kunena/attachments/1259/ArdumuverBestckung2015-04-221115.pdf Build instructions]
* [http://www.ardumower.de/media/kunena/attachments/905/TranslatedcopyofPrototypPlatine.docx.pdf Build instructions (English translation)]

Robot PCB v1.2 (minor layout changes)
* [https://github.com/Ardumower/ardumower/raw/master/pcb/megashield_svn_1.2_geschlossen/ardumower%20mega%20shield%20svn.pdf Schematics]
* [https://github.com/Ardumower/ardumower/tree/master/pcb/megashield_svn_1.2_geschlossen/Platinenbilder Photos]
* [http://www.ardumower.de/media/kunena/attachments/1259/ArdumuverBestckung2015-04-221115.pdf Build instructions]
* [http://www.ardumower.de/media/kunena/attachments/905/TranslatedcopyofPrototypPlatine.docx.pdf Build instructions (English translation)]
* [https://github.com/Ardumower/ardumower/raw/master/pcb/megashield_svn_1.2_geschlossen/Dokumentation/WorkaRound20150527.pdf WorkaRound20150527]
* [https://github.com/Ardumower/ardumower/raw/master/pcb/megashield_svn_1.2_geschlossen/Dokumentation/WorkaRound20150530.pdf WorkaRound20150530]
* [https://github.com/Ardumower/ardumower/raw/master/pcb/megashield_svn_1.2_geschlossen/Dokumentation/Motor-EntstoerungREV20150531.pdf Motor-decrease noise REV20150531], [http://www.ardumower.de/media/kunena/attachments/1725/Motor-EntstoerungREV20150531.pdf (English comments)]
* [https://github.com/Ardumower/ardumower/raw/master/pcb/megashield_svn_1.2_geschlossen/Dokumentation/WORKSHOP%20Protector-Board.pdf Protector board]

Robot PCB v1.3 (in development)
* simplified design (Due adapter will be externally)
* motor driver protection
* battery-off circuit, safety-button
* sets 'reference-design' and required modules: 3x DC/DC, RTC, IMU

'''NOTE:''' The schematics and PCB files were created with KiCad. They can be downloaded from [https://github.com/Ardumower/ardumower/archive/master.zip github] and can be edited by open source KiCAD software (Download [https://docs.google.com/uc?id=0BzTsqkQk2FRsSEhOR2tVc1p4LVk&export=download here] or [http://iut-tice.ujf-grenoble.fr/cao/KiCad_stable-2013.07.07-BZR4022_Win_full_version.exe here]).

=PCB jumpers=

{| class="wikitable"
|-
! 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=

{| class="wikitable"
|-
! 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=

{| class="wikitable"
|-
! 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.

[[File:warning.png]]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.

<gallery>
File: Dcdc_noise.jpg | NOTE: Keep away coil/pre-amplifier from DC/DC converters!
</gallery>

=Download and flash Arduino code=

<b>NOTE</b>: If you have never worked with Arduino before, read our <b>[http://wiki.ardumower.de/index.php?title=Arduino_first_steps 'Arduino first steps' introduction]</b>.

You have two options:
* Download [https://github.com/Ardumower/ardumower/releases github code (recommended)] OR
* Download [http://www.ardumower.de/index.php/de/downloads v0.9.3 code (old, not recommended)]

Finally, download and start the [http://arduino.cc/en/Main/Software 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).

[[File:warning.png]] Note: Always verify that the pin configuration in your Arduino code (config.h/mower.cpp) matches your actual circuit!

=First-time calibration=
==Wheel motors==
[[File:warning.png]]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:

<blockquote style="background-color: lightgrey; border: solid thin grey;">
<pre>
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...
...
</pre>
</blockquote>

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

==ADC calibration==
Run the ADC calibration once (either via serial console with command 'd' or "pfodApp->ADC Calibration"), so that the received signal is symmetric around zero.

=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.

[[File:warning.png]] 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.

<gallery>
File:Ardumower_sensor_counter_plotting.jpg |Sensor trigger counters
File:Ardumower_plot_sensors.jpg |Sensor measurement values
</gallery>

=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 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.

=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'.

The settings can be adjusted via Android phone ([http://wiki.ardumower.de/index.php?title=Bluetooth pfodApp]).

<gallery>
File:Cheat_sheet.png | General settings
File:Speedcontrol.png | Motor speed settings
File:Ardumower_config_files.png | General config file idea
</gallery>

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.

=Further links=

www.wiki.ardumower.de - Benutzerbeiträge [de]

Ardumower PCB