I have a robotic mower (https://www.worx.com/landroid-robotic-lawn-mower-wg794.html) which I would like to protect from theft. The idea is to create deterrence and try to scare would be thieves from actually picking up the device and running off with it. The device itself can detect if lifted up and puts out a weak beep and shuts itself off. To turn it back on again, you need to supply a passcode to make it work. Though this would make the device unusable to the thief, it is otherwise lost at this point. If I can scare them off to start with, that would be a better option I think. I have a little electronics background, but I am not an electronics expert by any stretch of the imagination. I can build projects off of diagrams, and electronics is sort of a passive hobby for me.

I intend to use a loud buzzer like this one: https://www.ebay.com/itm/283055776692. All I need is something of a sensor that would sense that the device has been lifted off the ground (maybe at a height of =/>6in) and send out a trigger to set off the buzzer. I am thinking maybe an ultrasonic sensor attached to device to measure the distance would do the job. Not sure how to design the circuit though or which sensor to buy. I don't think an optical sensor would be very reliable this being a mowing robot, I figured it will get the sensors dirty in no time rendering it useless.

Looking for ideas. Thank you.

 

A simple tilt switch will do,

https://uk.rs-online.com/mobile/p/p...MI1IWTjb2_3gIVx-d3Ch2BIgc6EAQYASABEgKNCPD_BwE

Or if you want to go more expensive search "altitude sensor"

https://www.ebay.co.uk/i/1919665823...3%26rvr_ts%3De87525e41660a99c5686a94cfff14b68

The best option is to use a perimiter detector first, like an ultrasonic or pir sensor in your garage, to warn you earlier of an intrusion.

 

Yes I have thought of the tilt switch. This however wont work if somebody picks it up fairly balanced straight off the ground. My worries about this device is that it will go to the whole length of my lawn, and when it's in the farthest corner, somebody can pick this up without me noticing. I really like this robot mower. It works like a roomba for your lawn. The manufacturer can actually really improve on the theft deterrence feature of this device. The built in warning system is very short and only audible when your 2 feet from the device. Will look into that altitude sensor. Thanks for the suggestion.

 

A lever-operated microswitch? The lever would normally slide over the ground and keep the switch "off".

 

Yes I have thought of the tilt switch. This however wont work if somebody picks it up fairly balanced straight off the ground.

My experience is tilt switch will work fine ... to be sure put 2 or 3 in at different angles so whichever way it's tilted , even slightly , the alarm will sound ... I think they're ten for a few euros on eBay ... they will work

 

hi,
If I had a $999 mower that only weighed 20lbs, I would pick it up and store it in my garden shed or a secure building.

E

 

Keep it simple.

You are correct, any fancy electronic sensor will be fouled with gunk and fail in no time.

 

Replace the weak beep with a recording of a blood curdling scream. Make it flash lights as well, really bright LED's that flash on for an instant and then are off for about a second. The scream and the blinding lights are something they will not be expecting. It's likely they may swallow their teeth then poop then out.

 

I have a robotic mower (https://www.worx.com/landroid-robotic-lawn-mower-wg794.html) which I would like to protect from theft. The idea is to create deterrence and try to scare would be thieves from actually picking up the device and running off with it. The device itself can detect if lifted up and puts out a weak beep and shuts itself off. To turn it back on again, you need to supply a passcode to make it work. Though this would make the device unusable to the thief, it is otherwise lost at this point. If I can scare them off to start with, that would be a better option I think. I have a little electronics background, but I am not an electronics expert by any stretch of the imagination. I can build projects off of diagrams, and electronics is sort of a passive hobby for me.

I intend to use a loud buzzer like this one: https://www.ebay.com/itm/283055776692. All I need is something of a sensor that would sense that the device has been lifted off the ground (maybe at a height of =/>6in) and send out a trigger to set off the buzzer. I am thinking maybe an ultrasonic sensor attached to device to measure the distance would do the job. Not sure how to design the circuit though or which sensor to buy. I don't think an optical sensor would be very reliable this being a mowing robot, I figured it will get the sensors dirty in no time rendering it useless.

Looking for ideas. Thank you.

If you want to get fancy, a verbal protest originating from the device saying something like: "warning, this mower is protected by GPS location ... unauthorized operation is being detected and the proper authorities will be contacted" ... THAT will make any thief think twice before heading off with your property, even if the alarm message is false.

 

Many years ago I saw a commercial for some sort of theft deterrent system. A prowler approached a front door and tried to get in. Flashing lights (if I remember correctly) and a pre-recorded voice said something like "Warning: You have been detected by (some advanced) security system. Do not attempt to leave the premises or you will be vaporized." The "Would Be" thief tried to run and was vaporized. I'm still trying to find where I can get that system.

Had to be some 40 years ago. Don't remember exactly what the commercial was trying to sell. But a system like that - now THAT's a "Theft Deterrent System".

I still like the idea of equipping a car with an alarm where some 50's horror movie with damsel screaming at the top of her lungs.

 

FLY PAPER!

 

Just get a big ugly dog and let it roam around your yard.

Dobermans, pit bulls, and rottweilers are a good choice.