220 Monster PCB Install Guide
Introduction to the PCB
The printed circuit board (PCB) is designed to make the wiring on the mower project as simple as possible. The locations of the solder points are designed to be close to the components and set out that a logical connection of the wiring can be made.
There are plenty of 5V and GND connection points, and the 3.3V connection points are located next to the relevant components. The PCB is clearly labelled where all the wires should be connected. The PCB is in itself an installation guide.
PCB Available here to purchase
In the PCB bundle you will receive the new PCB dedicated components required to make the installation.
The installation pack includes the DC Converter, Relay Switch, RTC Battery Holder (CR2032 battery not included), header pins. The PCB is already built from the manufacturer with the clock, LED's and resistors.
if you consider yourself a beginner at soldering please spend 5-10 minutes and watch a few soldering videos. Its good time spent and will improve the quality and fun of your build
Installing the PCB components
Ensure that the DC Converter is outputting 5V!
Connect and external 12V supply and ensure that it creates a 5V output. Failure to do this will damage the board and components on it.
To install the header pins please follow these steps.
To ensure the header pins have a good alignment with the PCB and component its best to insert to the header pins into the component. In this case the Arduino MEGA. After inserting the header pins into the Arduino MEGA, push the pin heads into the PCB. Using the Arduino MEGA as a clamp solder the header pins to the PCB. This keeps the pins steady and in perfect position.
Install the components using the above method when required as follows:
Electrical Insert Print
Print the new electrical insert panel and arrange the remaining components as shown. The PCB will give the optimised connection point to connect the components to the PCB.
Choice of Cable for Wiring
I recommend to use thin silicon wiring for the connections (18AWG). This wire is worth the investment to have a secure connection and durable cable.
The Arduino jumper cables are not really suited for soldering. They have 2 maybe 3 strands of copper in them which makes for a very unreliable solder joint.
Motor Drivers / Amp Volt Sensors
Connect the Volt / Amp sensors and the motor drivers as shown in the diagram below. the pins are clearly labelled on the PCB.
A connection points to measure the 12V battery voltage is provided for the Volt Sensor. The Amp sensor has a 12V connection point for the charge + wire.
A 12V connection point is also provided for the wheel motors. This 12V connection point needs to be shared by both wheel motors.
Connection Point Locations
For reference the rest of the connection points are shown here. A detailed guide for the connection of the various components is shown in the following instructions.
Compass and Mower Motor Connections
The compass and mower motor are connected as follows. A 3.3V output is provided next to the SDA and SCL connections. If you are still using the LCD screen then the LCD screen can also use the SDA and SCL pins. The LCD screen will however require a 5V source.
TFT and Rain Sensor
The TFT screen shield uses a separate Arduino MEGA. Before plugging the TFT shield into the MEGA solder 5V, GND and RX/TX wires to the TFT MEGA as shown below.
(If after uploading the code the touchscreen is not responding, see the guide on the Arduino Software page on how to calibrate the screen)
The TFT Shield can then be connected to the PCB as follows:
The rain sensor is also connected to the PCB on the dedicated pins. 5V and GND are also provided for the rain sensor.
Its a good idea to use a connector block when connecting the wheel motors to the wheel motor bridges. This allows a quick swap of the wires to get the correct rotation of the wheel. The wheel direction can be tested in the TEST menu using the Wheel Test function.
If the motors are not spinning correctly adjust the wires as follows.
The wire sensor detects the signal in the perimeter wire fence. The sensor is built as follows and fits inside the recess at the front of the mower.
Ensure the 11P Inductor is soldered directly to the Amplifier. When testing you should get (negative) values of -1000 near the wire and (positive) values of +400 when the mower is outside of the wire (Run the wire test). If your negative and positive values are switched, then either swap the Inductor legs around, or simply swap the wires around on the perimeter transmitter
The magnification of the amplifier can be adjusted by turning the set screw. Ensure the pads are bridged on the lower side of the sensor.
The sensor is connected to the PCB as follows.
The sonar array is connected as shown. The PCB provides individual GND and 5V outputs for each sonar module but these can be grouped together as shown below to reduce the wiring.
12V Battery and Charge Pins
The PCB really simplifies the 12V and charge circuit as dedicated pins are provided on the PCB. The PCB takes care of routing the 12V charge to the battery. (A wire from the Amp sensor to the 12V+ pin shopuld have already been made in the step when connecting the volt and amp sensors)
Connection is as shown.
Connect the micro-switches as shown. No 5V voltage is needed for the micro-switches.
Connect the tilt sensors as follows.
All the major components should now be connected. If you are using an ESP32 CAM or an RTK GPS feature please see the instructions on the build pages. Dedicated pins are provided on the PCB for these features.