Raspberry PI-based, Phone-controlled, First-person-view Lawn-mower.

Meet Lawny! It’s a lawn mower with a first-person view camera that allows you to cut grass while controlling a remote-controlled robot!

I’ve built it using a Raspberry PI, H-Bridge, electric motor, and camera. It can be controlled from a mobile phone or a desktop.

The project's main idea is to control a lawnmower using a phone and see the exact same picture as a lawnmower.

Here is the full video of its creation and all the concepts that are described in this article:

https://www.youtube.com/watch?v=4OQUo0V-8QY

Supplies

Raspberry PI 5 https://nerdythings.io/url/raspberry-...
Raspberry Pi Camera Module 3 https://nerdythings.io/url/raspberry-...
Windshield Wipers Motor https://nerdythings.io/url/wind-shiel...
Grass cutter electric motor https://nerdythings.io/url/motor-12v-30w
Relay https://nerdythings.io/url/relay-5v
Wires https://nerdythings.io/url/jumper-wires
H-Bridge https://nerdythings.io/url/h-bridge-12v
Steel Razors Trimmer Head https://nerdythings.io/url/steel-trim...
Power Bank https://nerdythings.io/url/power-bank
12V 9AH battery https://nerdythings.io/url/battery-12...
A rear wheel https://nerdythings.io/url/powertec-w...
Front Wheels (7inch) https://nerdythings.io/url/lawn-mower...
Craftsman instruments https://nerdythings.io/url/craftsman-...
Grooved Step Drill Bit Set https://nerdythings.io/url/step-drill...
Soldering https://nerdythings.io/url/soldering-kit

System Design

I have a Steel Razors Trimmer Head. If I add an electric motor, it will be a grass cutter. The motor rotates the blades, and they cut the grass. Simple.

If I want to control the motor, I need a relay and a controller. In my case, I used a Raspberry PI 5 (because I had it). However, any Raspberry device could support pulse width modulation and a camera.

That will be a static lawn mower. But I want to cut grass everywhere, not just in one spot, and I want to be able to turn the mover left and right.

So I am adding two more electric motors. The construction will be heavy, so I need power, not speed, and I will use windshield wiper motors from a real car.

The first limitation is that I need two Pulse Width Modulation channels to control a single motor. But I have two motors, which means that I need four channels. To solve this problem, I am adding two more relays to switch the signal between pins. Further, I need to see where the lawn mower is going, so I am adding a camera module to the Raspberry PI. Additionally, I need some power sources. To prevent power drop elements that consume a lot of current, I will use a separate battery for the motors and a power bank for the Raspberry PI and electronics.

And finally, I will control this system from a mobile phone with a cross-platform application through wi-fi.