Cartell Free Exit Sensors Open on Exit, Not Arrival

Cartell’s vehicle sensors are free-exit devices — they open the gate as a car drives out, not as you arrive. A magnetometer at the gate reads any moving steel, so it lets every car out without a remote, but it can’t tell your car from a stranger’s. That’s why it stays exit-only, and why opening the gate for your car as you pull up is a different job.

Cartell’s vehicle sensors are free exit devices. They open the gate automatically as a vehicle drives out, so you never have to stop and hunt for a remote on your way off the property. That is a useful thing, and Cartell does it well. What a free-exit sensor does not do is open the gate for you when you arrive — and that difference is the whole story.

How Cartell free exit works

Cartell’s detection is built on a magnetometer — a sensor that reads the movement of steel. A probe is buried in the driveway or mounted on a post near the gate. When a vehicle moves through the detection zone, the sensor recognizes the mass of moving metal and sends an open signal to your gate opener.

The clever part is what it ignores. Because it is looking specifically for moving steel, it does not fire for a person walking up, a dog crossing the driveway, or a leaf blowing past. Cartell leans on this hard in their marketing, and it is a fair claim — “only moving steel” is a real advantage over motion sensors that trip on anything warm.

Two things are worth knowing about the detection itself:

• The zone is small. The headline range numbers you see (often quoted in the hundreds or thousands of feet) are the radio distance between the sensor and the receiver, not how far away it detects a car. The actual detection zone is a few feet around the probe.
• The vehicle has to be moving. A magnetometer reads change. That is perfect for a car rolling out of a driveway, and it is part of why free-exit is the natural fit.

The part that trips people up: exit is not arrival

Here is the distinction that sends people down the wrong path. A free-exit sensor opens the gate when a car drives out. It does not know whose car it is, and it is not meant to. That is a deliberate design choice, not a shortcoming — because a sensor that opened the gate for any approaching vehicle would open it for anyone. On the way out that is fine; you are leaving your own property. On the way in, opening for any car is the opposite of security.

So when someone asks “will a Cartell sensor open my gate when I get home?”, the honest answer is: not the way you are picturing. To open the gate as you arrive — and only you — you need a device that knows the difference between your car and a stranger’s. That is a different job entirely, and it is the one Cartell leaves open. (For more on why approach-based auto-open is harder than it looks, see why phone geofencing struggles with driveway gates.)

Where Cartell wins

A credible comparison names the things the other option does better, and Cartell has several:

• Nothing to carry in the car. The sensor lives at the gate, so any vehicle triggers the exit — guests, deliveries, a second car — with no device to install or remember.
• No subscription. It is one-time hardware, like a good tool should be.
• Very low false triggers. The magnetometer approach holds up here; it does not fire on people or weather.
• Driveway awareness. Cartell’s broader line adds chimes and notifications so you know when a vehicle enters the driveway — a real security feature, and one an arrival tag does not try to replicate.
• A 50-year track record. Founded in 1975, sold through gate installers nationwide, with a long reliability history. That matters for something bolted to your property.

If your goal is “let every car out automatically” or “know when a vehicle is in the driveway,” Cartell is a strong, proven answer.

Where a hands-free arrival trigger fits

The other half of the problem — opening the gate for your car as you pull up — is where a GPS arrival tag comes in. Instead of sensing metal at the gate, it identifies your car and triggers the opener as you reach home.

This is the job Proxly is built for. A small Tag rides in your car and has its own dedicated GPS — not your phone’s location, not a cloud service — so it knows when your car has arrived and opens the gate as you approach. It wires to the two low-voltage terminals on the opener you already own, so it works across opener brands, and there is nothing buried in the driveway. No remote to press, no app to unlock, no subscription.

The one-line way to hold the two apart:

A free-exit sensor opens the gate when a car drives out. An arrival tag opens it when your car arrives in.

They are not really rivals — they solve opposite directions. A household that wants both fully hands-free could run a free-exit sensor for leaving and an arrival tag for coming home.

Cartell vs a hands-free arrival tag, side by side

	Cartell free exit	Proxly (arrival tag)
Opens the gate on exit	Yes	Not the job
Opens the gate on arrival	No	Yes
Opens for your car specifically	No (any moving steel)	Yes (your Tag)
Device in the car	None	A Tag on the windshield
Anything buried in the driveway	Yes (probe)	No
Driveway awareness / alerts	Yes	No (not the job)
Works across opener brands	Yes (wired to opener)	Yes (wired to opener)
Subscription	No	No
Price	~$199-$341	$199 early bird ($499 retail)

How to choose

• You mainly want to roll out without stopping → a Cartell free-exit sensor is a clean, proven fit.
• You want to know when a vehicle is in the driveway → Cartell’s awareness line is built for exactly that.
• You want the gate open as you pull up, for your car only, with nothing in the ground → that is an arrival tag’s job, not a free-exit sensor’s.
• You want both directions automated → run both; they complement each other.

Why drivers pick Proxly for the arrival half

If the thing that bugs you is the coming home moment — pulling up to a closed gate and reaching for a remote — that is the exact gap Proxly closes. One Tag in the car, wired to the opener you already own, and the gate opens as you arrive. Any car, any of the opener brands Proxly supports, no app required, no subscription. Proxly is pre-launch: you can reserve a spot for a refundable $20, which locks the $199 early-bird price (first 100; $499 retail after).

If you want to see every way to open a gate from the car — remotes, mirrors, apps, sensors, and arrival tags — the full rundown is here.

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Last updated: 2026-08-01. Cartell product names, specifications, and prices are drawn from publicly available manufacturer and retailer sources at the time of writing and may change; verify current details with Cartell and your retailer before purchasing. Proxly is an independent product and is not affiliated with, sponsored by, or endorsed by Cartell or any other company mentioned. All product names and trademarks are the property of their respective owners. Spotted something inaccurate? Email getproxly@gmail.com.