DIY Speedometer using GPS Module Arduino & OLED

Overview

In this project, we will make Speedometer using GPS Module, Arduino & OLED Display. A speedometer or a speed meter is a gauge that measures and displays the instantaneous speed of a vehicle. Many speedometers use a rotating flexible cable driven by gearing linked to the vehicle’s transmission. But many modern speedometers are electronic.

In order to build a GPS Speedometer, we need a GPS Receiver. The most popular GPS Receiver is ublox NEO-6M GPS Module. But we will use Quectel L86 GPS Module as it is tiny with a very small antenna. By interfacing L86 GPS Module with Arduino and 0.96″ OLED Display, the speed related parameters can be displayed on OLED Screen.

Bill of Materials

To make Arduino GPS Speedometer, we need following components. You can purchase all the components online from Amazon.

How GPS measures Speed?

GPS devices can measure speeds in two ways:

1. Method 1: The first and simpler method is based on how far the receiver has moved since the last measurement. Such speed calculations are not subject to the same sources of error as the vehicle’s speedometer (wheel size, transmission/drive ratios). Instead, the GPS’s positional accuracy, and therefore the accuracy of its calculated speed, is dependent on the satellite signal quality at the time. Speed calculations will be more accurate at higher speeds when the ratio of positional error to positional change is lower. The GPS software may also use a moving average calculation to reduce error. Some GPS devices do not take into account the vertical position of the car so will under-report the speed by the road’s gradient.

2. Method 2: Alternatively, the GPS may take advantage of the Doppler effect to estimate its velocity. In ideal conditions, the accuracy for commercial devices is within 0.2–0.5 km/h, but it may worsen if the signal quality degrades.

Quectel L86/L80 GPS Module

The L86 Module is an ideal solution for wearable fitness devices due to its ultra-compact design and low power demands. Its Low Power feature enables GPS connectivity at around half the power consumption of normal mode while in static receiving mode. Combined with its precision and high sensitivity, this makes the L86 suitable also for a broad range of IoT applications such as portable devices, automotive, personal tracking, security, and industrial PDAs.

The L86 has a patch antenna on top measuring 16.0mm × 16.0mm × 6.45mm, with 66 acquisition channels and 22 tracking channels. It acquires and tracks satellites in the shortest time even at the indoor signal level. The module operates at 2.8V~4.3V with a typical power consumption of 20mA and in Standby mode power consumption is around 1.0mA. To learn more about the L86 GPS module, you can check the L86 Datasheet.

The Quectel L86/L80 GPS Module has 12 pins as shown in the image below.

The L86 is a tiny SMD-type Module that doesn’t have any male/female header pins for testing. So you can use the male header pin with 2.54 spacing and solder them on the L86 PCB from the bottom.

Once, you solder all the 12 Pins on the L86 Module, the Module becomes breadboard friendly. You can now insert the module on the breadboard easily.

Arduino GPS Speedometer Circuit Diagram

Now let us see the circuit diagram of Arduino GPS Speedometer. The connection diagram is fairly simple as shown in image below.

The Quectel L86 GPS module has 12 pins but we will only use 5 pins for our project. Connect the VCC & GND pin of L86 to the 3.3V & GND pin of Arduino. Connect the V_BCKP pin of L86 to 3.3V, if this pin remains unconnected the module won’t work. The Rx & Tx pin of L86 goes to Arduino digital pin 2 & 3 respectively.

The OLED Display is an I2C Module. Connect the VCC & GND Pin of OLED to Arduino 3.3V & GND Pin. Similarly, connect the SDA & SCL pin to Arduino A4 & A5 pin respectively.

Project PCB Gerber File & PCB Ordering Online

If you don’t want to assemble the circuit on a breadboard and you want PCB for the project, then here is the PCB for you. The PCB Board for GPS Speedometer is designed using EasyEDA online Circuit Schematics & PCB designing tool. First the schematic is designed and then the schematic is converted into PCB.

The Gerber File for the PCB is given below. You can simply download the Gerber File and order the PCB from ALLPCB at 1$ only.

You can use this Gerber file to order high quality PCB for this project. To do that visit the ALLPCB official website by clicking here: https://www.allpcb.com/.

You can now upload the Gerber File by choosing the Quote Now option. From these options, you can choose the Material Type, Dimensions, Quantity, Thickness, Solder Mask Color and other required parameters.

After filling all details, select your country and shipping method. Finally you can place the order.

Source Code/Program

The best part about the L80 GPS Module is, it supports Tiny GPS++ Library. Download the library and add it to the Arduino library folder. Apart from Tiny GPS++ Library, the code also requires SSD1306 Library called as Adafruit SSD1306 library.

Here is the complete code. You can copy the code and upload it to the Arduino Nano Board.

Testing the Arduino GPS Speedometer

Upload the above code to the Arduino Nano Board. Initially the OLED Display will show no data. This is because the L86 GPS receiver is not synchronized with satellite system.

After waiting for a while, the GPS starts receiving the signal from the nearest satellite system. The receiving of signal and synchronization with satellite depends upon the indoor-outdoor conditions. After proper synchronization with the satellite, the OLED screen shows the speed in kilometers per hour (kmph). It may show zero speed when it is kept at rest.

While the GPS Speedometer is placed in a moving vehicle it starts showing the speed in kmph. It also shows the total satellite connected to the system as well as the altitude in meters.

Video Tutorial & Guide

This is how we can build an Arduino Speedometer using GPS Module and Arduino. There are so many applications of Speedometers. It can be used to measure the speed of cars, bicycles, walks, races, or even boats, buses, trains, bicycles, and planes.