Buy a Directional Compass for Your Car
The compass has been a useful tool for navigation for hundreds of years. It indicates the direction of north. With a compass and a map, navigation may be performed without requiring a modern Global Positioning System (GPS.) Directional compasses are available for use in automobiles and can help direct you to your desired destination. Follow these tips to buy a directional compass for your car.
Steps
- Decide between a bubble compass or a digital compass. A bubble compass is read as the position of the needle floating in a housing. The housing is filled with fluid to allow the needle to float freely. A digital compass will read the needle for the driver and present the direction on a display.
- Learn about the features of car compasses before choosing a compass.
- Ensure that the compass has a means to mount securely to a car windshield or dash.
- Evaluate the calibration features of the compass, which will compensate for the magnetic field disturbances caused by a running car.
- Make sure that the compass is adjustable in position. The driver of the car should be able to read the compass without grasping it or taking his eyes off the road.
- Determine if the compass must be mounted on a level surface. If a bubble compass is chosen rather than a digital compass, it must be adjustable to keep the compass level in the bubble.
- Decide if you want the additional feature of a thermometer. Some car compasses come with built in digital thermometers.
- Determine your compass lighting needs. A backlit compass should be chosen for night driving.
- Determine how the backlit is activated. This is usually accomplished by pressing a switch on the compass. The backlight may then be turned back off or be allowed to time out. The compass will turn the backlight off automatically after a period of time determined by the compass. This will preserve battery life.
- Check the battery needs of the compass. Most compasses run on AA or AAA batteries. Find out how long the batteries typically last in the compass. Check the manual or installation guide to learn how to change the batteries.
- Confirm that the compass has a calibration feature. The compass must be set outside of the car. The compass must then be adjusted after mounting inside the car. This should be done with the car running to account for disturbances in the magnetic field caused by the metal of the car, magnetic noise from the engine and electronic noise from the car accessories. Having the car radio on for this calibration offers the most precise calibration.
- Become familiar with the calibration controls of the compass. Check the manual or installation guide of the compass. Be sure that you understand the calibration controls and can effectively control the calibration.
- Choose the type of digital display to be used. These can be giving general north (N) and south (S) headings. Displays that give readouts in degrees of the compass also are available.
- Pick a compass that has a readable display location. Displays can be mounted on the body of the device itself. They also are available in small remote display boxes. Displays can be placed on the rear view mirror of the car.
- Find the car compass that meets your needs. Website, automobile accessory catalogs and auto parts stores sell compasses. You can expect to pay around $10 for a basic bubble compass, and more than $40 for a more fully featured digital compass.
Warnings
- A bubble compass must be kept level. The needle must float freely on the liquid in the compass. Failure to level a bubble compass may cause the compass needle to drag along the compass housing, making the needle stick and providing inaccurate readings.
- A running car disturbs the magnetic field around it. Calibrating the compass accounts for this. You will not get an accurate reading from the car compass if the car is not running.
