DIY: Adding Digital Odometer and Modifying Auto AC

Once again, driven by excitement, I wanted to create something fun. I saw other people’s cars with LCD screens and automatic air conditioning, looking quite high-end. Since we can’t afford to buy a new car but still want to play around, what should we do? So, I started another DIY project, which is still not finished. I work on it whenever I have time, so it will take a while.

First, I need to write a program to display the car logo on startup; otherwise, it will look like a knockoff!

The LCD display interface needs some modifications, as I want to add a cruise control feature. For safety reasons, I won’t add it! Actually, I still want to test it out because it’s fun.

Debugging the program is quite nerve-wracking 😢

I found the wiring diagram for the Buick dashboard online; otherwise, I wouldn’t know how to modify it!

Disassemble, disassemble, disassemble, then find the input wire for the speed sensor. From this, I learned that the speed is represented by 12 high-level pulses for each complete wheel rotation.

Next, it’s easier; I need to take power, take pulses, and adjust the voltage for the background light, a total of four wires.

Now I can start drawing the circuit diagram, but it’s still not finished! It will take time to work on!

Let’s create a mock-up to see what it looks like; this is basically the design.

The circuit board looks like this, with two knobs to adjust the temperature and speed.

Here’s the physical object, the circuit diagram, and a small portion of the program.

3D modeling mock-up 1

3D modeling mock-up 2

First, I simulated it a bit; doesn’t it look somewhat real? Installing it here took a long time and many trials before I decided. I didn’t want to damage the car’s original structure; it’s removable, but the adjustment is a bit troublesome. However, it’s not something we need to adjust often, right?

I tested it on the road; I modified the program many times to get the speed just right.

Finally, it’s almost done; for now, it’s at a standstill. I don’t have free time every day, and I just want to work on it when I have an idea, so updates will be slow. Thank you, everyone.

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