Schlagwort: Robotic Lawn Mower

  • Can this tiny lawn mower robot cut it in the real world?

    Can this tiny lawn mower robot cut it in the real world?

    Reading Time: 2 minutes

    We’re finally starting to see robotic lawn mowers gain a little bit of traction as prices come down and consumer trust goes up. They work a bit like Roomba vacuums and pathfinding sophistication varies from one model to the next. But even the most basic models are still a lot more expensive than their secondhand gasoline powered cousins. So, Nikodem Bartnik decided to cut costs by making his DIY lawn mower robot very small.

    To keep this prototype simple and affordable, Bartnik decided not to bother with any kind of mapping, pathfinding, object avoidance, or perimeter detection capabilities. It has no autonomous navigation features and instead the user must control the robot themselves. But sitting on a chair in the shade is still a lot better than pushing around a heavy lawn mower. Though the robot is only about the size of a dinner plate, so mowing an entire lawn will take a while.

    Bartnik constructed the robot out of a sheet of plywood and 3D-printed parts. It has two driven wheels and each is turned by a small geared DC motor. The third wheel on the front is a caster that spins freely. An Arduino UNO Rev3 board controls both of those, as well as the brushless DC motor that spins the blades. Those blades swivel where they attach to the central hub, so centrifugal force causes them to swing outwards. Finally, the Arduino can communicate with the user’s smartphone through an HC-05 module for remote operation.

    This won’t rival your dad’s zero-turn mower when it comes to power, but that wasn’t Bartnik’s intention. Instead, he sees it as a machine for giving the lawn a light trim every day or two before it can get too long. It’s slow, but that won’t be an issue if Bartnik implements autonomous navigation in the future.  

    [youtube https://www.youtube.com/watch?v=oJbYpmUHdLs?feature=oembed&w=500&h=281]

    The post Can this tiny lawn mower robot cut it in the real world? appeared first on Arduino Blog.

    Website: LINK

  • Centimeter-scale lawn mower positioning without GPS RTK

    Centimeter-scale lawn mower positioning without GPS RTK

    Reading Time: 2 minutes

    Arduino TeamJuly 27th, 2022

    GPS is perfect for navigating roads, because that doesn’t require much precision. But GPS is only accurate to several meters, which means that it is unsuitable for applications that require more precise positioning. GPS RTK (real-time kinematic) systems can achieve much greater accuracy, but they are complex and require a subscription to a correction service. Viktor Kurusa needed accurate positioning for his robotic lawn mower, but didn’t want to resort to GPS RTK. Instead, he used a few Arduino boards to enable UWB ranging for centimeter-scale positioning.

    UWB (ultra-wideband) is a radio technology that the FCC opened up for consumer and commercial applications in 2002. It is ideal for transmitting large amounts of data at short ranges. It is also possible to use UWB to calculate distances by measuring the ToF (time of flight) between a “tag” device and an “anchor” device. Using two anchor devices, one can triangulate the position of the tag on a 2D plane. With three anchors, one can determine the tag’s exact location in 3D space.

    Kurusa used this UWB positioning capability for his robotic lawn mower’s navigation. The lawn mower incorporates several boards: an Arduino Due, two Nanos, and four SparkFun Arduino Pro Minis. The latter four boards connect to Decawave DMW1000 UWB transceiver modules — three of them for the remote anchors and one of them for the onboard tag. The Due board acts as the primary onboard controller and runs FreeRTOS, monitors an MPU6050 accelerometer, and drives the robot’s motors through an H-bridge. One Nano board interfaces with ultrasonic sensors for obstacle avoidance and the second Nano monitors a LIDAR sensor, which the system checks if the ultrasonic sensors detect an obstacle.

    With all of that hardware working in concert, Kurusa has a robotic lawnmower with a sophisticated sensor array. It knows exactly where it is in the yard, which lets it accurately follow paths while mowing. If something unexpected enter’s the mower’s path, such as a kid’s soccer ball, the mower will detect it and attempt to navigate around it.

    Website: LINK