Here is the overview of our electrical system.

We are using a Motorola HC08-QY4 microcontroller to program our automated mower. Pinout

It is capable of handling both C and Assembly programming languages. View our software page to find out more about its automation.

As with other methods of determining how to make an automated lawn mower, we again used a matrix to find how we were going to be able

to do this. This matrix explores some sensor options.

1= worst

5= best

Below you can see an approximate representation of the sensors on board the mower which will assist it with detecting obstacles,

remembering its location, and returning to the docking station for recharging.

This circuit will direct the Agro-bot back to the docking station in the event that the batteries lose too much charge.

The infrared waveform that permeates from the docking station is unique, so ambient light will not affect the navigation

of the Agro-bot.

Here is a picture of one of the pairs of ultrasonic sensors that will detect objects in its path while mowing. Specs

Since the output of these sensors is a Pulse Width Modulated (PWM) signal that is proportional to the distance,

it first must pass through a Low-Pass Filter (LPF) before entering one of the inputs of the microcontroller. This DC

value is fed to an Analog-to-Digital Converter (A/D C) and read by the microcontroller.

Our wheel encoders will measure the rotations of each drive wheel. These are integral in determining where the Agro-bot is

on the lawn it happens to be mowing. They are also used to steer Agro-bot the correct amount when needed.

The front bumpers are connected to a simple electrical switch that will interrupt any function the Agro-bot is

currently performing. If these bumpers are activated, it clearly indicates that the Agro-bot has collided with something.

The rotary reel will shut off in such a case, while the Agro-bot attempts to maneuver around such an obstacle.

When the batteries are low, the Agro-bot will need to recharge at the docking station.

We have chosen to use Lithium-Ion batteries for their supreme charge holding ability compared with other types of batteries.

Our motors are driven by H-bridge circuits. There is an H-bridge circuit for each of the three independent motors.