Gebildet 5pcs Recessed Wired Security Window Gate Contact Sensor Alarm Magnetic Reed Switch(Black),Magnetic Door Sensor,Magnet Near - Connect Circuit, Magnet Away - Break Circuit

I brought these wondering if I would ever use them.Long story short, they work like a dream

Used these with a Shelly DCi4 to turn my loft lights on when I open the hatch and it works great. Not the nicest looking so I use them on the inside of the hatch so it can’t be seen.

Connected these to an ESP32 and then stuck to my door. ESP32 is running ESPHOME which is then connected to Home Assistant. I get instant notifications when the door is open.These reed switches aren't overly sensitive so they do have to be quite close together to actually get the 'closed' signal.They were extremely easy to setup and good value for money.

Well, they work. As for a range of about 10-15mm, that’s highly optimistic. The best range I could get from all three, was about 4mm. So, providing whatever you’re using them for is almost touching, you’ll be fine. Anything more than 4mm, no chance.

Tested all OK on receipt, as others not, operation is quite close (~5mm). Bought nc/no as description of others ambiguous

Simple, quick, no problems, I would have preferred a PVC-PVC coated two core cable rather then two separate PVC core cables as it looks tidier but they did the job fine, I have them installed and they work. No issue.

I bought these for operating some 12v LED strip lighting in a wardrobe, so the light comes on when the door is opened. I first did a test on each by switch by holding it close to my ear and bringing the magnet close; only one of them made a click sound the others were silent. I also tested them with a resistance meter and the only reliable one was the one that had clicked. The others were occasionally able to switch when bringing the magnets close but not often, even when the magnet was touching. I was therefore only able to use the one unit from the pack of three. I returned the faulty units and happily received a full refund from Amazon. However I certainly wouldn't recommend these, particularly for a burglar alarm situation unless they were thoroughly checked and sufficient quantity bought to ensure the required yeild.

These arrived very promptly next day. The five switches and magnets were nicely packaged in a wee plastic box. Screws and sticky pads were included to give alternative fixing methods. The switches have insulated leads of around 30cm in length and at the end the leads are bared and tinned. They seem to work well with the switch operating when the magnet is at a distance of around 10mm. The are described as normally closed but, to me, this was a bit misleading, so I tested them. When there is no magnet the switch is open (non conducting). When the magnet is close the reed switch closes and conducts. I would call that normally open but I suppose it depends on your view of what is normal.