Automatically shut down a lawn mower when a metal object is detected. Lean how I use a inductive sensor with a relay to make this happen. Swap to an capacitive sensor and it will detect rocks, metal and even your finger.

, https://i.ytimg.com/vi/eDZeLPgYBvg/hqdefault.jpg

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29 Comments

  1. We need it for rocks & tree roots. Maybe some sort of sonar type device to detect dense objects.

  2. i dont know why it wasnt made before, its not like these thing will break and make them buy a new one… its more dangerous to kill someone(make less consumer to make more money !) as you posted this vid on mythbuster (confirmed kill by lawnmover) … anyway good job

  3. Very cool. This is the Tesla of lawnmowers! But as others have commented, I wonder about the effectiveness of your invention while mowing at a normal walking speed (or speed of the self-propelled mower). You were moving very slowly in your opening demo. It takes several seconds for an engine to shut down. And the ignition coil has to be grounded continually while the engine slows to a full stop. But the ingenuity you have demonstrated is fabulous! Looking forward to your next revision!

  4. The one sensor is good for a proof of concept imo. Id be curious on testing how wide of a range the sensor has left, right, and height wise, how many sensors you need to cover the front, how big of a metal object it can detect, and if you could use the lawn mower motor itself to power a rechargeable battery for the sensors. Someone else recommended a bypass which I thought was a smart idea too. I can see this as very marketable if done for a decent price! You could even sell kits to attach to lawnmowers

  5. Add an override lever for when you know you're passing over and in-ground structure that won't be affected by the mower. Great idea though!

  6. Interesting concept but it needs refinement. The motor wont stop quickly enough to prevent damage, And the detected zone is very small…. But a little refinement and design can fix that.

  7. Interesting concept but for it to be sold you are going to have to keep the dead man control also at the handle bar. This could be a 2nd kill switch. Also people hit metal objects but also stumps and concrete/ rocks that cause damage. So a sensor to detect objects based on height might be better. Just my thoughts.

  8. Great idea! Sewer drains and other metal objects don’t stand a chance, Well done.

  13. Very interesting concept. I believe the sensor you're using searches for obstructions from metal objects. There is coding involved in my suggestion but what if you replaced that with an optical sensor with a wide angle lens that was triggered by any foreign object in the path?

  15. This is great! Good for people like me who know a lot about botany but not a lot about machinery. Bravo – liked and subbed

  16. So what if it's on the side does it only work if you drive dead center What if the metal object is closer to the tire the blade will still hit it but will the sensor still pick it up if its way on the side

  19. What is the voltage on the ignition coil? If it is 10,000 volts it likely exceeds the voltage rating of the relay and wire to the relay. Also voltage can jump through wire insulation to the mower body, or to the human body if a finger gets close enough to the wire.

  20. Can try extending the support-arm with the equipment on out a few inches to allow a bit more time for the blade to slow down along with multiple sensors all in series for better coverage. Maybe some kind of plastic guard too so that the sensors+power supply and relay don’t get mucky/wet from grass

  22. This works in theory but not in practice. As mentioned, the metal object needs to be in the center of the mower but the mower takes a few seconds to shut down. Your current relay only triggers while the metal object is right under it so running over a tool like that at normal mowing speed would barely make the motor miss a stroke let alone shut off. The fix for this would be a timer that keeps the relay closed for 3-4 seconds after any contact with a metal object.

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