How to use your phone as a HUD speedometer at night
Short answer: turn on a HUD (mirror) mode, lay the phone flat on the dashboard just under the windshield, and lower the brightness until the reflected speed is clear but not glaring. It keeps your eyes on the road instead of on a phone mount.
Set it up
- Open Gaugely and tap the HUD toggle. The numbers flip left-to-right and fill the screen.
- Place the phone face up, as close to the windshield as you can, roughly in your line of sight.
- Use a non-slip mat so it does not slide in corners.
- Keep the screen on; HUD mode does this for you.
Get a clear reflection
Dim the screen at night: too bright and the whole windshield glows. Steep windshields give a fainter, double image, which is normal for a phone HUD. Daylight washes it out, so this is a night and dusk tool.
Speed limit alert
Set your own limit in settings. When you go over it, the HUD turns red, with optional sound and vibration, so you notice without reading the number.
Nothing else on the glass
A reflected banner ad is distracting and, in apps with explicit ads, embarrassing with family on board. Gaugely hides all ads in HUD mode, and never shows pop-ups while you are moving.
Check your local laws on objects on the dashboard, and never adjust the phone while driving.
FAQ
How does a phone HUD work?
The app mirrors the numbers left-to-right. Laid flat under the windshield, the glass reflects them the right way round.
Does a HUD work in daylight?
Poorly. The reflection is faint in bright light; it works best at night or at dusk.
Can my family see it safely?
In Gaugely the HUD screen shows no ads, so nothing else is reflected on the glass.