I'd like to put a contact sensor on my mailbox, but we have a long driveway -- almost 600 feet, to go by Google Maps. (We share the driveway with another house in front of us.) I get that it's out of range of Z-Wave and Zigbee, and even Wi-Fi. Are there dedicated devices that could do a longer range hop and then connect to something? I see a thread about wiring a receiver into a contact sensor with terminals, but those seem to be mostly about motion sensor.
Does anyone have a long-range contact transmitter/receiver that could be hooked up this way, or is it just something I can't effectively do?
I don't think you're going to find one. Even the Xbee Pro modules, which have super strong radios, only have a range of 300 feet line-of-sight outdoors. And they are more powerful than any zigbee devices I have seen. There are radio signals that can reach that far, obviously, but then you have to ask yourself about power consumption and would a device last more than a couple of hours on a batter that was trying to use them. I just don't think this one is going to be in the cards.
from the listing for the device:
Works up to 300 feet away under ideal conditions
That is only half the distance trying to be covered here. Not just a bit more....TWICE as far. This isn't going to work.
Yeah, 600 feet is going to be a stretch. I did the modification to the transmitter, too, moving it outside the metal mailbox. As shown at the end of the ST thread I posted above
My receiver is located in the center of the house, so it is penetrating a couple of walls.
That thread also makes a good point about the mailbox being on the other side of the road, in which case the delivery vehicle is going to block the signal.
I guess it all depends on what failure rate you find acceptable. Personally, I wouldn't invest this kind of money unless it was going to work 100%. Especially when it has to be modded before you can test it, meaning you can't return it if it doesn't work.
I have a similarly long driveway. I did above-mentioned Mighty Mule hack -- connecting a Ecolink contact sensor to the Mighty Mule which has no problem with the distance. Works like a charm. And a fun little project.
Run 600’ of 2 core wire to the mailbox.
Connect to a standard magnetic alarm contact at the mailbox
Connect the other end (in the house) to a contact sensor joined to HE
That would work if you can easily hide the wire etc
1200' (there and back) is going to give you a LOT of voltage drop though. How many miliamps does a contact sensor put through the reed switch? (i've never checked). At 100mA you're going to get 76% voltage drop at that distance.
The only reason I asked was I had typed up the exact same post and was about to hit save. Then I thought of voltage drop. So i thought maybe you'd already considered it. No worries. It is a good idea to try. Wouldn't cost you anything...you can try it right in the house.
I thought about doing that --and probably would have done it if I had an available conduit. ( I have some going out to the road, but not over to the mailbox. Apparently, I wasn't thinking of mailbox announcers in the 1980s when I built the house.) But for <$50 I decided not to get into trenching. hhh.
Nope
However; the alternative would be to use 12vdc and a small low volt relay (taking into consideration the voltage drop) to open/close the contact sensor
I'd actually thought, use a 12 volt source out to the mailbox reed switch, then a voltage divider to send that signal into the contact sensor in the house. but that just gets REAL complicated.
I would just shove 12vdc to the reed switch and measure what comes back.. no calculations required for wire gauge etc
Then a suitable reed relay or transistor circuit to switch the HE contact
Well, yeah. If you want to go that route, if you used an Arduino or ESP board, you could probably get away with sending out 5v and using the standard analog input to measure the voltage.
Actually, i just checked....if you send out 5v, you would have enough at the end to still trip the digital input on an ESP board. you'd have about 2.5v. You wouldn't even have to use an analog translation.
However, in all this talk of the electronics, we've forgotten that this solution also means you'd have to bury 600 feet of low-voltage landscape wire. LOL
