The speedometer holds immense importance in cars, vehicles and almost all other means of transportation as it indicates the speed at which you are moving or travelling. This becomes all the more important on roads with a speed limit -- which, quite naturally, is most of them. Therefore, the speedometer is unarguably one of the most essential components in a vehicle's instrument cluster. Over time a digital speedometer can require repair or a complete replacement, sometimes even going faulty due to some wiring malfunctioning. Fortunately you can build your own high-tech digital speedometer in a few steps.
Plug in the GPS module straight into your Package tracker. Place the Micro SD card in the 5-volt step-up board's socket.
With the help of a soldering iron, link the female as well as the male headers of your LCD backpack right through your LCD's graphic board. Plug in the headers once they have been soldered. Employ the power link straight from your battery to the 5 volt step up board. Connect the step up board straight within your serial graphic backpack's output.
Decide and determine the size of the circular shape which will act as your speedometer's speed indicator. Draw in the digits and the shape of your speedometer on your serial graphic backpack. Start with the digit 0, writing it at the circle's bottom left while move forward in the clockwise direction by adding numbers with an increment of 10.
With the help of a calculator, work out the coordinates of the line which points out your speed while your car is on the move. Place it in such a way that it starts off from the centre of your speedometer's circle and maintains a length of about 20 pixels. Placing the 'Line' on your serial backpack is also a valid way to create a line speed indicator.
Use a scientific calculator to figure out the speed ratio while setting up the speedometer. This reduces the chances of error. Use 'Speed' command to derive your speed from the GPS module. Post this speed up on the LCD.