DIY OBDII Led Display and Scan Tool (Version 2)

Andrew Overby
9 / 6 / 2018

Since its completion in April 2018, my DIY OBDII dash display (see link at bottom of page for more) had been working like a champ, but it started to encounter frequent problems that became rather annoying. These issues were:

1)    Overheating
2)    Durability
3)    Faulty connectors

Fixing the problems became the next task, analyzing the faults and finding efficient ways to fix them. Overheating was caused simply because there was not much (if any) airflow below the dash where the control box was stored. This proved to be a large issue especially on summer days. When the Arduino would get hot, it works less efficiently, causing it to run slower, or sometimes crash.


SolidWorks Model

GrabCad provides an easy way to download free 3D models from gears to electronics. It gives a nice 3D model to use in a final assembly and helps with interferences between parts.

In order to solve the overheating, I determined that more vents throughout the enclosure as well as a small fan would do the trick. Although the Arduino was not overheating immensely, the case will get hot underneath the dash, especially on hot days. A 5V fan was a perfect solution for the fix and was an easy incorporation to the current logic level circuit.


3D Printed Parts

On my first control box iteration, I had a large problem with my parts peeling off the print bed during mid-print even with a large brim. To fix this problem, a purple washable glue stick will do the trick. No more peeling parts! Also note that it makes the part harder to take off the bed after printing, for which I recommend purchasing a glass bed as well.

Durability was a problematic issue with the past enclosure. Due to 3D printing conditions that were not ideal, the parts to the case warped and bent in every direction to where the pieces would not fit properly together. Since I did not have a 3D printer of my own at the time, I was forced to stick with the current configuration before I could make changes. The new box not only looks better, but has more slots for hot air to exit.



Having an internal PCB with permanent connectors not only made the control module more robust, but the electrical signal strength also benefitted as a result. 

Whenever my car would hit bumps, there would be issues with the Arduino cutting power and I later found out it was because the connectors would barely lose continuity from the forces of the car. To fix the problem, I needed a more secure connector, and a D-sub proved to be the right fit. These connectors can stand up to the test, and have very tight contacts that do not rely on pins for their continuity.


Old vs. New

Added aesthetics were also a focus of mine during the product redesign.

Since these improvements, I have not seen any hiccups with the current gauge performance. The next task on the list will be improving the assembly of the gauge pod as well as the user interface. Minor improvements to software were also made during this process; however, they were only small bugs that were not worth noting.


The Finished Product

The case took about 16 hours to print with high resolution and low speed settings.