Smartphone Heads Up Display for Car




Have you ever been driving and look down at your speed only to realize your hand or even the steering wheel is in the way. You can move your hand or duck your head to read it, but that seemingly insignificant glance equals more time NOT looking at the road. If only there was a way to check your speed without having to take your eyes off the road without having to purchase an expensive OBD (or do you have OBD2?) heads up display system for your car.

Wait! There is!

Follow these simple steps to turn your old smartphone into a safe, reliable, accurate and effective heads up display (HUD).

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Materials

You simply need the following:

  • Smartphone
  • Velcro with self-adhesive backing
  • Scissors to cut velcro
  • Window/dashboard cell phone mount (optional)

Step 2: Download an App

In the Play Store or App Store, search for HUD or Heads Up Display. There will be dozens to choose from. For the purpose of this Instructable, I have downloaded the app JustHUD from the Play Store.

Step 3: Attach the Velcro

Cut the Velcro strips to fit the back of Peel off the protective strip from one part of the Velcro and attach it to the back of your phone.

Do not peel the second strip yet.

Step 4: Find the Best Location

Activate the app. Lay your cell phone face up on the dash just under the windshield. Adjust it to the best location that will give the highest visibility and reflection.

Peel the protective strip from the second half of the Velcro and lay your phone back in the spot that had the vest visitibility. Press and hold the phone down to get a good adherence to the dash.

This will prevent the phone from sliding off the dash while driving.

Step 5: Test It Out

Go for a drive. You should be able to see your speed projected onto the windshield while you drive.

The actual display of the phone will be the mirror image, so do not worry about that, it will project properly on the glass.

As you can see in the video, it is accurate. It uses GPS location and satellite tracking to determine speed. There is no WiFi or data signal required.

Step 6: Optional Step

In bright light, or driving into the sun, the display may wash out and become invisible.

In that case, you can use the window/dash mount cell phone holder and place it on the windshield about the same place as the HUD.

You will have to adjust the settings of the app to show the display regular instead of mirrored, but it will work just as well.

I hope you find this helpful and easy to do.

Drive safe! Drive Friendly!

First Time Author Contest

Participated in the
First Time Author Contest

Car and Motorcycle Contest

Participated in the
Car and Motorcycle Contest

Phone Contest

Participated in the
Phone Contest

Safety Challenge

Participated in the
Safety Challenge

Be the First to Share


    • Made with Math Contest

      Made with Math Contest
    • Multi-Discipline Contest

      Multi-Discipline Contest
    • Robotics Contest

      Robotics Contest

    10 Discussions


    1 year ago

    If anyone comes across this, and can help me, I would be so very grateful!!! I realize it's been well over a year since the last comment was posted, but I'm hoping someone will see this! It says in 'Step : 5 Test It Out' that it doesn't need a WiFi, or Data signal??? I don't understand how it can give you continuous "real time" navigation, and / or speed, without some form of a signal??? Whenever I use my GPS location feature on my phone when travelling, and I lose my signal, it shows my car at a standstill??? When my signal comes back, it updates, and shows my car in the correct place. So what am I not understanding here??? How does it show you real-time, accurate, location and speed, without cell signal??? AH! I'm so confused?!?!?! Please help! I live in an almost entirely "dead zone", so this would be a handy tool in my toolbox, if it does actually work that way! Thank you guys! Any help is greatly appriated!!!

    3 replies

    Reply 10 months ago

    If you have an OBD2 data port buy a bluetooth OBD2 scanner and it will give you the speed, rpm and a plethora of other info. You'll have to use an OBD2 app like Torque instead. There are free and paid versions. I use this method in my wife's LX470 to compensate for the intermitent guage cluster. Torque has a HUD display function for just this purpose. I use the free version BTW.

    Screenshot_20181201-112310_Torque (Lite).jpg

    Reply 10 months ago

    I have checked out Torque, also. Yes, I agree, it is a great product. It does have loads of diagnostics and information on your vehicle. I am just too cheap to purchase the OBD2 adapter. That is why I went the direction I did.


    Reply 1 year ago

    AH! This is a great question!

    It does not need a Wi-Fi signal nor any data signal. It does use the built in GPS locator services of the phone itself. There is a setting within many smartphones that enable more accurate location services using Wi-Fi and Data services, but it is not necessarily. That is how emergency 911 services can track locations with cell phones. It uses satellite technology to determine your location and the distance traveled by coordinating the longitude (degrees, hours, minutes, seconds) and latitude (also degrees, hours, minutes, seconds) and changes it into speed. Just like any standard, store-bought GPS unit would. The reason it shows you at a standstill is because it can no longer track your progress or location, so it defaults to last known location. Again, just like any standard GPS unit would. The only difference is the HUD does not require any mapping to display, only the speed and depending on the display you choose, your exact location (within about 10 feet)

    Just because you may live in a cellular dead zone, there are very VERY few locations in modernized countries that have GPS satellite dead zones.

    I am not sure if I answered your question well enough of not, but I hope so. I would be happy to clarify anything further, if I only muddied the waters even more.

    Thank you for checking it out and asking! You are right about it being a handy tool in a tool box! I keep an extra old phone set with it, in case my primary goes out.


    Reply 3 years ago

    Good day, curtis.newton.104203.
    I can appreciate your opinion.

    Please know that every time you put down your Shake Weight and change out of your Snuggie. Or when you climb back into your Ford Edsel, crank up the music on your Microsoft Zune and drive to McDonald's for your delicious Arch Deluxe. As well as, the times that you check your email on your Apple Newton while drinking a refreshing Crystal Pepsi, with a side of Olestra infused WOW! Chips, that your opinion not only is appreciated, but you single-handedly increased my views and comments stats.

    For that, curtis.netwon.104203, I say thank you for checking out my instructable!