Background:
I have made A LOT of progress and a significant time investment into a project creating some really awesome gauges for my car. See videos below: (also see attached pictures for construction)
They work great immediately after installation, but I am having reliability issues, which is really discouraging me from continuing the project. I am looking for advice on how to make these more reliable.
Both projects share similar components, similar programming (copied portions), and similar design strategy.
The only differences are:
-Dome light gauge I think has more expensive 7-seg displays and board by OSHpark
-Round gauge has almost all made in China LEDs/7-segs, board by SeeedStudio. It is a two part board and has two MAX7221 linked together to control all the tons of LEDs.
Relevant Components include:
-Arduino (Pro mini 5v version)
-MAX7221
-3-digit 7-segment Common Cathode (some from China cheap, some from DIGIKEY $$$)
-Bi-Color LED common cathode 3mm LEDs from china, cheap
-Circuit boards by SeeedStudio (boost gauge)
-Circuit board by OSHpark (the 3x 3digit/7seg dome light gauge)
-All soldered connections
-Chinese buck/switching power supply (same for all) 12v->5v
Problems/issues:
- Cold Start reliability:
On a cold day, the 7-segments will refuse to light. They will remain unlit until power is cycled, AND the environment is warm enough. On a nice spring/summer day they will light the first time and remain functional.
The the dome light gauge is more likely to light on a cold day, and seems to be more reliable. The circular gauge has the worst reliability. Works well in the warm environment, either initially or after the restart.
- 3mm LED failure
A few of my 3mm LEDs have failed. The failure is every 4th led (which seems to indicate a connection issue more than an actual failed LED)
*** I previously purchased a cheap water temp gauge, disassembled it and remote mounted the 7-seg far away from the "brain" of the gauge using a ribbon cable. it had crappy cold start characteristics also. But was a finished product, from China***
I assumed LED technology would be good enough that any manufacturer would make a quality product. All LEDs are powered/regulated by the MAX IC chips...
I did plan on trying to market these but they are far from being polished enough to do so.
My suspected issues are:
--LED manufacturer quality (ability to operate in "extreme weather" temps -20F-120F)
--Assembly skill (my-error)
Any input or opinions/experience with similar issues on your LED projects?
