The Mercuino - Mega 2560 Controller

The Arduino Mega 2560 was chosen because it offered a robust and flexible design along with a vast amount of In/Outputs. A big challenge was to properly route all wiring while still keeping the design modular and flexible.

The Mercuino Brain

I choose RJ45 jacks and CAT5 cables because:

• CAT5 cables are widely available and everybody I know has a pile of them laying around
• The cables have 8 strands, enough to talk to most controllers and avoid multiple routings to a single component
• They clip in securely into the jacks and wont come loose
• The plastic tubing protects them from harsh conditions

Lessons Learned:

• The Arduino is powerful but has its limits, running all the relays and the bluetooth module from the 5V regulator is not reliable. Using 5V regulators to power each component from the Cars main 12V supply is a much better approach than torturing the little Arduino Board.
• RJ45 Jacks are a great but use up a lot of room. For future design id rather cut CAT5 cables in half and run the Plug end outside from the controller with plenty of slack. The cut end would be soldered onto jumper wires so the pin assignment can be changed easily. This approach allows for maximum flexibility of the design. Running all the In/Outputs outside the box is quite a challenge so before doing anything else i would take care of this issue.

Building Process: