My company car that I normally drive tends to have a “small” problems from time to time, the speedometer fall to 0 Km/h when driving (after some time it resumes again).
Normally this is not a big issue since if you know how to drive a car, you are not, I hope, always looking to the speedometer. You now more or less the speed that you are driving. The problem present it self when you need to decrease speed to the road limit that you are entering and you notice that “the speedometer is down”.
This presented like a good opportunity to build a new project, “The GPS Speedometer”. Of course the ideal solution would be, really repair the car or use a normal GPS or use an app with this function but what would be the fun in this 🙂
Step 1: Components
I selected theDFRobot Dreamer Nano V4.1 because it has a usb plug that I can use for power and a compatible breadboard pinout.
Check DFRobot wiki page for more info regarding this microcontroller
I’m using the UBX-G7020-KT, that comes with an integrated antenna and allows to change the refresh rate until 10Hz(for this project this featuring can came in hand).
On the DFRobot wiki page you will find more info regarding it.
I wanted to have a good display without “blowing” the budget, my choose was the OLED 2828 Display Module. Check again the wiki page for some more info.
The power for the system will be provided by the car cigarette lighter socket.
This time I when for designing a casing and 3D printing it.
Step 2: Connect the Components
The design with the LED’s was not my first choice. So initially I designed the schematic without LED’s
But in the end I added 10 LED’s (7 Green and 3 Red’s).
I forgot to take some pictures of the assembly process, so what I can say is that everything is assembled in the prefboard, in one side is the oled display and in the other the microcontroller and connections. In order to make this easy leave the oled display for last since some of the connections will be done on its back.