Newbie proximity sensor question

Hi all,

I’m brand new to the community, Arduino programming, and proximity sensors, in general. I am looking for some very high-level guidance on a project I am considering.

The problem I’d like to solve is that I want to make sure I never leave my house without a couple of items. Ideally, I’d like to be able to slap some sort of small, passive, chip on these items and have a FOB on my key chain that beeps if I get too far from them (i.e., out of the house). My first thought was RFID, but from what I can find it has too short of range. I also considered Bluetooth, but again, the range is probably too short and it’s not passive.

My first thought was that an Arduino-based prototype would be a good place to start, but I’m also open to completely non-Arduino suggestions. Essentially, I don’t know where to start my research and I’m looking for some help reining in the options.


I don't think you have many options. A UHF RFID would fit the bill but it is very expensive, arround $400 minimum.

BTLE beacons.
Still dear.

How things change…I used to write a quick checklist.

Thanks for the suggestions. I'll look into BTLE beacons - I wasn't aware of that technology.

Although not passive, using a network-enabled smart base (a la Arduino) that things with RFIDs sit on or near might be another way to go. That would get around the RFID range problem.

@bluejets - checklists are so 20th century :slight_smile: Actually, one of the things I don't want to forget is life-saving medicine for our daughter, so I'm more looking for a backup system. I've since learned that there is at least one company who will start shipping something for this purpose this year, but unfortunately it's not going to be cheap. We'll probably get a device anyway, because it's peace of mind that we can afford, but seems like a fun challenge to see if it can be done a different way.

Just thinking. When I leave my house, it is almost always in my car. I do leave to take walks, but in that case I remain close to home.

So if you are always leaving in your car, use an opposite approach. Have the car turn on a circuit using an RFID scanner to look for the RFID tags on the important items. If it doesn’t find 'em, you’re still in the driveway.

For women, it's called a purse.