Simple Car Compass

What's on the screen

One dashboard, split between a speed gauge and a direction panel. Upright they stack; turned sideways in a mount they sit side by side. Nothing moves unless the car does.

Speed

The current speed as a whole number, in mph or km/h — the picker remembers your choice between launches, and the other unit sits underneath in smaller type.

The arc

A ring that fills with your speed, coloured against the road's posted limit, with a tick where the limit falls and a LIMIT 30 badge repeating the number.

Direction

A fixed-marker heading tape: 90° of compass slide past a centre marker, labelled every 22.5°. The distance a mark travels is the size of the turn. It is damped, so the ribbon glides instead of jumping between readings.

Street

The name of the road you're on, when the app can get one.

What the colours mean

On a road with no known limit the arc isn't drawn at all. Green there would claim the app knows the posted speed when it doesn't.

Two sensors, and it says which

While you're moving, direction comes from GPS course over ground and the label reads COURSE — the direction the car is actually travelling. Stopped, or with no course available, it switches to the magnetometer and reads HEADING, so a parked car points where it faces rather than where it last went. The compass follows the device orientation, which is what makes it read correctly when the phone is clamped sideways.

What it needs, and what it won't do

Street names and speed limits come from OpenStreetMap

iOS has no speed-limit API — not MapKit, not Core Location — so the street name and the posted limit are read from the maxspeed tag on OpenStreetMap, through its Nominatim reverse geocoder. Road lookups are off until you turn them on, from the information button in the corner. With them on, an approximate location (rounded to about a metre) goes to Nominatim; speed and compass readings never leave the device. Turning the setting off clears the road data and cancels any lookup in flight.

Lookups are throttled well inside Nominatim's one-per-second policy: at most one every three seconds, only after moving 50 m, cached for five minutes within a car's length, with a one-minute backoff after a failure. Street and limit data is © OpenStreetMap contributors, under the ODbL.

What it is not

• Not a substitute for your speedometer, and not a satnav. There is no map, no route, no turn-by-turn.
• No offline road data. Without a connection, speed and direction still work; street name and posted limit don't.
• Not every road has a posted limit in OpenStreetMap — most residential streets don't, and the arc stays empty there.
• It keeps the screen awake while it's open, because a dashboard that dims is a dashboard you can't read.

The beta

The first build passed Apple's beta review on 31 October 2026. The beta is small and invitation-only: ask me and I'll add your Apple ID, and TestFlight emails you the build. There's no public link, and no App Store release yet.

Request an invite — the draft asks for the three things I actually need: your Apple ID email, your device and iOS version, and how the phone sits in the car.

Testers are asked to mount the phone and drive: confirm the speed tracks the speedometer, that the arc changes colour at the sign's number, that the tape follows a turn without spinning at north, and that the reading switches from COURSE to HEADING when you stop. Feedback by email is the fastest route — it reaches me, not a ticket queue.

Privacy, in one line

No account, no analytics, no advertising, no server of mine. The only thing that ever leaves the phone is the road lookup you switch on, and that goes to OpenStreetMap. Read the full policy.

Get in touch

Beta invites, bug reports, or a feature you actually want while driving:

• CarCompass@steveogden.dev
• github.com/stvogdn