Wire vs Wireless Robot Lawn Mower Which Is Better?
There are two types of robot lawn mowers on the market today. Robot lawn mowers that come with a boundary wire (wired robot mower) or come boundary wireless (wireless robot mower).
As technology evolves, robot mowers are showing increased intelligence and the ability to achieve exceptional results. Several studies show owning a robot lawn mower not only saves time and money but also delivers a better healthier lawn. However, when it comes to wired and wireless robot lawn mowers it’s essential to consider the differences, lawn condition, suitability and robotic mower model.
This article will address the key differences between wire vs boundary wireless robotic mowers, and what to look out for when buying a robot lawn mower.
What Is A Wireless Robot Lawn Mower:
A wireless robot lawn mower operates without the need for a physical boundary wire to navigate the lawn or field that it is mowing.
How does a wireless robot lawn mower navigate
Instead of relying on a boundary wire, wireless robot lawn mowers use technology such as GPS, mapping, vision or a combination of these to navigate. Not all wireless robot lawn mowers are created equally and will have varying results due to how they have been built, what technology they use and the research and development that goes into maintaining and updating the app and firmware.
Having a basic understanding of how the technology works will help you determine whether a wireless robot lawn mower will suit your lawn.
How does a robot lawn mower navigate:
Robot lawn mowers use satellites to navigate, there are 4 systems under the GNSS (global navigation satellite system)
These are:
- GPS: 32 satellites, orbit period of 12 hours
- GLONASS: 24 satellites, 11 hour orbit period
- Galileo: 30 satellites, 14 hour orbit
- BeiDou: 44 satellites, 7 are geostationary, 24 hour orbit.
- And two regional systems: QZSS and IRNSS
Why is GNSS compatible important?
GNSS compatible equipment can use navigational satellites from other networks beyond the GPS system and can therefore provide more accurate location information than GPS alone.
How does GNSS Work?
GNSS (satellites) broadcast their position and time to a receiver, there are two receivers: stationary (RTK station) and moving (robot mower).
It takes time for the satellite signal to travel to the GNSS receiver. Delays such as trees, tall buildings, reflections and atmospheric distortion can degrade the accuracy.
What is RKT and how does it improve accuracy?
RTK stands for Real Time Kinematic. The RTK station has a fixed location with known coordinates. It continuously receives signals from GNSS satellites, its fixed location allows it to calculate the delay for each satellite. The RTK station then transmits in real time to the robot mower the calculation so it can calculate its own location with greater accuracy.
Because the RTK station doesn’t move, its position can be more accurately calculated over a longer period of time.
Why do wireless robot mower get lost?
The RTK station can only send out delay information for the satellites it can see/is connected to. The robot mower can only correct satellite information for the satellites it can see and receives information for. If the robot mower and RTK station are not connected to the same satellites, the robot mower will be unable to correctly determine its position.
Trees and large buildings can disrupt the satellite signal. New Zealand conditions are vastly different to overseas where most robot mowers are tested. In New Zealand we have a lot of trees, shrubs, buildings and sheds which can all distort the satellite signal and stop the robot mower from connecting to the satellites. This is why even if you install the RTK station on the roof (which is advised), you are not guaranteed to have a working wireless mower, the robot mower also needs to be able to connect to the satellites.
This is why we haven’t brought a wireless robot lawn mower to the market until now.
Also, what works one day, might cause a headache another. Due to the orbit periods, satellites are not always going to be in the same position relative to your position, this means satellite signal coverage can change from day to day.
What’s the solution?
The solution is additional technology and not solely relying on satellites. The LawnMaster X7 has RTK, Vision, VSLAM, AI and IMU.
VSLAM and IMU
Visual Simultaneous Localisation and Mapping. Designed to be used in places without a good satellite signal. The camera is used to identify visual inputs on the lawn. Like all technology this is not a 100% accurate method, the camera can register tall grass as an obstacle. Also poorly lit areas, fog or rain can impair visibility. Obstacles lower than 6 inches might not be registered.
VSLAM can be used in conjunction with IMU Inertial Measurement Unit, it matches where it thinks it has gone based on things like how much the wheels have turned and how much inertia it has felt in each direction, it then matches that with visual inputs relative to where it has last seen these visual inputs, using this to figure out where it is and where it has been.
The problem with solely relying on gps is it can have “drift” over time. GPS drift is when the device can’t accurately determine its location, thinking it is a few steps or meters away from its actual location. This means it can travel over larger distances, small areas can accumulate larger and larger over time. Which can be a problem if you have a pool or live on a busy road. VSLAM allows the robot mower to “reset” when it recognises something it has already seen. However, keep in mind technology can sometimes be unpredictable and just because it has VSLAM does not mean it is fool proof.
What Is A Boundary Wire Robot Lawn Mower:
Boundary wire also known as perimeter wire enables the robot lawn mower to navigate an area of lawn or field. The boundary wire is made of a thin wire insulated with a PVC sheath to protect it from environmental elements such as rain and sun.
The boundary wire acts as an invisible fence as the charging station emits a small amount of electricity through the wire, creating a magnetic field. The robot mower detects the signal, guiding the robotic mower, preventing it from entering or mowing areas it shouldn’t. The robot mower will stop operating if the boundary wire is severed or the connection is lost. The mower uses sensors and onboard algorithms to stay within the designated mowing area and avoid obstacles, mowing in a systematic pattern to ensure an even and efficient cut.
How Does A Wired Robot Lawn Mower Operate?
- Installation: This involves mapping out and laying the wire around the boundary of the lawn, pegging it down. Depending on the type of robotic mower this might require a specialist which could increase the long term costs of owning a robot lawn mower especially if it needs tweaks and adjustments.
- App connectivity: Connecting the robot lawn mower through the app allows you to customise various settings and mowing schedules.
- Recharging: The robot mower is equipped with sensors that monitor its battery level. When the charge drops below a certain threshold, (predetermined by the manufacturer) the mower navigates its way back to the charging station.
Boundary Wire Installation And Common Issues To Be Aware Of:
The boundary wire is installed on the surface of the lawn, held down by pegs. Over the coming weeks the wire becomes invisible to the naked eye as it settles into the lawn and grass growth occurs. The boundary wire can also be installed no deeper than 5cm below the surface; however, burying the wire in the initial first couple of weeks could cause tweaking and adjustments to become harder.
It’s important to review the instructions and map out the wire placement before installation to avoid mistakes or having to relay the boundary wire through improper planning. Proper planning reduces the time it takes to install the boundary wire.
The most common issues that occur with wired robot lawn mowers are due to incorrect installation through not reading the instructions. Robot lawn mowers are incredibly simple machines to use especially with ample guides and video tutorials available online. It is vital to make yourself familiar with the instructions and plan the wire placement before installation.
Common issues that can occur from not reading the instructions are:
Sharp Corners: Excessively share angles in the wire’s layout can lead to weakening and eventual breaks in the wire as it settles into the lawn
Distance from the edge: If the wire is not the correct distance from the edge the ‘cut to edge’ feature won’t be fully utilised and it may give sub par results
Damaging the wire: Damage can occur in the insulation of the wire during installation by hitting or striking the wire with a hammer. This can create micro cracks and allow moisture to penetrate the wire and cause damage.
Peg Insufficiency: Insufficiently securing the wire with pegs can lead to wire slack, leaving the wire susceptible to being severed by the mower blades. This is at heightened risk during installation as owners usually skip the step of initially mowing their lawn to save time, (the wire site on top of long grass as it takes a couple weeks to settle into the lawn) this couples with setting the mower blade to the lowest height setting can cause the mower to pick up the wire and sever it.
The wire acts as an electric field signalling the mower where to operate, if the wire is severed the robot mower will stop operating until this has been fixed.
Tension: if the wire is under tension while installed, it can cause the wire to develop weak points as it settles into the lawn and cause breaks in the wire. To remedy this, leave a little slack while installing the wire but ensure it is secured to the ground with adequate pegs.
Length: Not factoring in enough “margin or error and adjustment” or sectioning off obstacles such as trees throughout double looping like below can cause the wire to need extensions or re-laying, it’s important to measure and plan before installation.
A handy tip the experts use, is to set the cutting height a little higher while the wire settles into the lawn, this allows for easy adjustments to be made while the wire is visible and means the robot mower shouldn’t pick up and cut the wire.
Wired robot lawn mowers offer several benefits but they aren’t without their challenges. The installation is more labour intensive and compared to wireless robot mowers, any yard changes would take planning and effort but it isn’t impossible.
Depending on the wired model purchased the ongoing maintenance costs might outweigh the benefit of owning a robot lawn mower. For example, Ambrogio which is well-known in Europe is a complicated mower that requires professional installation and follow-up. If there isn’t someone in your area to regularly service the mower it can become very costly.
Wireless Robot Lawn Mowers - What To Be Aware Of:
There is a rush in demand for wireless robot mowers as they are increasing in popularity, driven by users seeking to avoid installing a boundary wire.
It’s essential to keep in mind robot mowers that perform well overseas, may not be up to New Zealand conditions. As technology evolves, new robot mower brands are entering the market at a pace not seen before. With testing predominantly performed in American and European countries before being launched in NZ. It’s essential to keep in mind robot mowers that perform well overseas, may not be up to New Zealand conditions as they are vastly different.
The other concern to keep in mind is to ensure support, repairs and spare parts are going to be available. There is no point buying a robot mower if you can’t have it serviced in 12-24 months time or the technology is no longer being supported by firmware and app updates.. Typically issues can be seen within 12-24 months if the robot mower isn’t made suitable for NZ conditions.
Other issues to be aware of, but not limited to:
- Drift, ending up in out of bounds areas and what this means for you (do you have a pool or live by a busy road)
- Lawn suitability, do you have good satellite coverage (will it work on your property)
Benefits Of Wired Robot Lawn Mowers:
Wire robot mowers offer the following:
Precision: Boundary wire robot lawn mowers follow a predefined path set by the boundary wire, ensuring accurate and consistent results. The cut-to-edge feature can be utilised with peace of mind the robot mower won’t end up in the garden or pool.
Efficient Coverage: Wired robot mowers are designed to cover the entire mowing area systematically, reducing the likelihood of missed spots or uneven cuts.
Reduced Manual Labour: Once the boundary wire is installed, the robot mower operates autonomously
Consistent Schedule: Wired robot mowers can be programmed to mow at specific times of day or night.
Reduced Landscape Damage: Robot lawn mowers are lightweight and distribute their weight evenly, causing less soil compaction and lawn damage compared to traditional mowers.
Can I set up my boundary wire but put the mower outside of it and let it navigate by bumping into my fence and house?
Unfortunately, the robot lawn mower needs to detect itself within the boundary wire in order to operate. If the robot mower is outside the boundary wire it will not operate and show an error on the app or screen.
Benefits Of Wireless Robot Lawn Mowers:
Wireless robot lawn mowers offer a number of benefits from fast, easy and mostly hassle free installation. Customisation is easy within the app, adding no go zones, out of bounds or editing the boundary, without reinstalling or moving physical wires.
Wireless robot mowers have more to offer on complex lawns, navigating trees, obstacles and crossing driveways or paths without requiring exposed boundary wires. Navigating from the front to back lawn without a connecting mowing strip is now a lot easier. The technology has also advanced to a point you can create lawn stripes and patterns, giving your yard a professional look. Obstacle detection allows the mower to avoid fixed obstacles like trees and kids play sets but it can also adapt to an ever changing environment such as rabbit hutches, and kids balls left on the lawn.
In conclusion, wired robot lawn mowers or perimeter wire robot mowers are the better option for areas with low satellite coverage and operating near a pool or busy road. However, a wired option may not suit your complex lawn, results you desire, ever changing environment or the size of your lawn. No technology is 100% fool proof or safe, so take these into consideration when choosing the best option for your lawn.