LAM Monster - Electrical Installation

LAM Monster Electrical Circuit Build with Power Motors

The following details the steps to build the main electrical board which is located under the main hood of the mower and how to connect the other sensors and drivers in the mower.  Please follow carefully the instructions and you will create a tidy main board for the mower.  This control board can be created outside of the mower.  Once the board is completed you can then screw it into the location points inside the hood of the mower.



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

Video 1         Video 2


Step 1 - Arrange Components

Arrange the components as shown in the diagram below.  Solder a black wire (negative) and a red wire (positive) to the DC convertor on the IN side.  This will bring 12V power to the DC convertor.  Ensure the cables are at least 20cm long.


Step 2 - Create a 5V Circuit

by turning the adjustment screw anticlockwise the 12V IN can be converted into 5V out.  Use a voltmeter to measure the output voltage and adjust it to be 5V.

This 5V output will power most of the boards and sensors in the mower.  Add 2 pieces of cable to the 5V output.  We will gather all the 5V power lines in the area shown. 




Step 3 - Power to the MEGA

Using a separate positive and negative cable bring the 5V power to the Arduino MEGA.


Step 4 - Real Time Clock and NodeMCU

Connect the Real Time Clock and NodeMCU to the 5V power.  The positive and negative cables can be ran underneath the MEGA to keep the install looking as clean as possible.  Run the signal wires from the pins shown on the RTC and NodeMCU to the MEGA.  I really find it best to solder the wires as over time the Arduino wire pins can come loose.



Step 5 - Relay Connection

Again run 5V power to the relay and connect the signal pin to the MEGA.


Step 6 - Motor Bridges

As you are using the power motors bridge 2 motor drivers as shown here.



The Motor Bridges do not require any 5V power supply.  Connect the signal wires to the MEGA as shown in the diagram below.





Step 7 - Prepare Motor Drivers for 12V

To prepare the motor driver for 12V power connect the 12V and GND pins of the motor drivers using thicker min 1.5mm silicon wire.



Step 8 - Volt Sensor

Connect the volt sensor to the 5V power supply and the signal pin to the Arduion Nano pin A2



Step 9 - Amp Sensor

Connect the ampsensor to the 5V power supply and the signal pin to the Arduion Nano pin A1



Step 10 - Rain Sensor & Nano

Connect the Arduino Nano to the 5V power supply and the serial communication pins to the Arduino MEGA.  Prepare a 5V wire (positive and GND) for the rain sensor which we will connect later.  Also prepare a signal wire from the Arduino Nano pin A3 for the rain sensor.



Step 11 - Compass Prep

The compass will run on 3.3V and requires a SCA SCL communication.  Prepare these wires for the compass.  The wires should be long enough to reach the compass module which will be located at the front of the mower.




Step 12 - TFT Touchscreen Prep.

The TFT touchscreen communicates to the MEGA via the serial communication.  Later in the build we will add a 5V power line to the lower section of the mower where we can connect the TFT screen to power.  2 data lines on the serial communication are required long enough to reach the TFT screen.



Step 13 - 12V Switched Circuit via Relay

The 12V power for the wheel motors and the blade motor is switched on and off via the relay.  12V power comes into the relay circuit (COM) from the battery source. The 12V positive wire then exits the relay from the NO (normally open side), one power line to the wheel motor drivers and one power line to the blade motor controller. 

The negative 12V cable is connected to the GND side of the motor controller.  (in step 7 we connected both controllers together, so both controllers will now receive power.)


Step 14 - Prepare Wheel Motor Lines and Cooling Fan. .

Connect the 12V cooling fan to the 12V and GND pins on one of the wheel motor contollers.  (The fan will switch on when the relay activates).  Add 2 wires per wheel motor driver long enough to reach the wheel motors at the back of the mower.





Step 15 - Add 5V for Sensors

In the next steps we will connect the sensors from the lower section of the mower to the MEGA.  This diagram gives an overview of which wires we will connect and their paths.  For now just add 5V+ and GND wires as shown that we can use to power the sensors in the lower section of the mower.


The build should now look this and have the following wires available for connecting the other sensors/motors etc in the mower.  The electrical plate can now be installed into the hood using the fixation points.




Step 17 - Group wires and cap, Install Rain Sensor, Compass.

The electrical plate should be installed in the mower hood.  Now its time to connect the other sensors and create the complete 12V circuit.

Group together the 12V lines and use an electrical connector plug to secure them.  Do the same with the wheel motor wires and the 5V circuit for the lower section of the mower.

Install the compass module and rain sensor using the pre-prepared wires from the previous steps.





Step 18 - Wheel Motors

Connect the wheel motors to the pre-prepared wheel motor lines.  If the connector blocks are used the wheel motor wires can easily be switched to ensure forwards, backwards left and right are all working correctly. 


If the left motor turns instead of the right, exchange both motor wires on the motor with the other motor wires.  

If the correct motor turns, but in the wrong direction just swap the 2 wires that are already on the motor with each other.



Step 19 - TFT Screen

Prepare the TFT Arduino MEGA (separate MEGA) with 5V, GND and 2 serial cable connections RX1 TX1.

Push the TFT Shield onto the MEGA making sure the pin alignment is correct.  Copy the BMP files from the ARDUINO Code folder onto a micro SD card and insert this into the TFT screen



Use the 3D printed TFT plate and clamp to hold the TFT shield securely and assemble it into the mower. 

Connect the 5V and GND from the TFT to the 5V output created for the lower section of the mower.  Then connect RX3 -> TX1 and TX3 --> RX1 to allow communication between the TFT Shield and the main Mower Arduino MEGA.

(If after uploading the code the touchscreen is not responding, see the guide on the Arduino Software page on how to calibrate the screen)



Step 20 - Blade Motor Controller and Blade Motor

Connect the pre-prepared 12V supply coming from the relay to the blade motor controller as shown in the diagram.  Then connect the 12V GND wire to the GND connection point on the 12V circuit.  For the LAM please daisy chain the +ve and -ve wires to each of the 3 motor controllers.







Step 21 - Blade Motor Controller Communications

Now connect the blade controller to the Arduino MEGA main board so the blade motor controller can be controlled by the Ardunio MEGA..

3 communication wires go to the Arduino MEGA.  The VCC and GND wires are connected to the lower 5V output point.

For the LAM mower again the communication wires need to be split into 3 wires and connected to each motor controller.






Step 22 - Sonar Array


The sonar modules are now connected.  Each sonar module requires a 5V+ GND Trig and Echo wire.  The 5V circuit can be connected to the lower 5V output point.  The 3 Echo and 3 Trig wires are connected to the Arduino MEGA on the pins 36 to 39 as shown below.




Step 23 - Wire Sensor

The wire sensor is prepared as shown in the following diagram.  The capacitor on the 200x Audio Amp shoudl be bridged by soldering the 2 pins on the lower side of the board.


The wire sensor is then connected to the circuit using again the 5V lower output as shown below.  The signal wire is connected the the Arduino MEGA pin A5.



Step 24 - Switch and Battery

The main 12V LiIon battery is connected to the 12V circuit as shown below.  The main power switch cuts power to all components once turned off.  A positive lead from the 12V circuit is ran to the volt sensor to measure the mowers battery voltage.





Step 25 - Charge Plugs & Amp Sensor

The battery needs to be charged even when the main switch is off.  For this reason the charge cables are ran to the battery plug before the main power switch.  The positive lead of the charge cable is ran through the amp sensor to measure when a charge is present.





Step 26 - Bumper Microswitches

The Front bumper microswitches are loctaed at the front facia of the mower.  They require a GND and a COM wire per microswitch.  (no 5V+ supply is required)



Step 27 - Tip and Tilt Sensors

Prepare the sensors and fix them into the 3D printed plate.  Ensure that the sensor head of the tip sensor is bent by 90°




Connect them to the circuit as shown below.




That completes the full electrical install.  All the components can be tested using the test function in the TFT display.