This is the standard, cheaper, version of the Rugged Arduino I used. It is up to you whether you think the standard version is needed or if your environment is harsh enough to necessitate the ruggeduino from rugged-circuits.com (no affiliation).

This allows you to convert a regular Arduino to screw terminals to make the connections much more robust. It also gives you some free prototyping space to create some small circuits.

This is the cheap HMI touchscreen I used for my project.

Note: this wire is very soft and flexible and works well inside the enclosure. However, consider firmer wire for engine bay wiring.

For safety and reliability, all power wires should have a fuse near their source. There should never be a direct path to a battery or power supply's positive terminal without a fuse in between.

for passing wires through enclosure walls and sheet metal

High quality connectors suitable for automotive use.

Used to crimp pins onto wires before inserting them into a connector.

Used to remove pins from connectors. Keep your hand out of the line of fire when using this, I cut myself multiple times when a finger was in the wrong spot.

These were used to convert voltage and signal levels between Arduino 5V logic, 0.8V triggers, and 12V. See wiring schematics and datasheets provided in the downloads.

If your transistors are used at a high duty cycle consider a heat sink to prevent overheating. This is unneeded for occasional switching.

This is a broad selection of resistors which is used to create voltage dividers and in all sorts of other areas in electronics.

These Printed Circuit Boards give you a place to create circuits and put your components.

I used these to breakout a 5V power source within my engine bay to minimize wiring to my 5V sensors.

The small enclosure works well for small projects, but if you're adding multiple PCB's consider a larger size.

DIN mounting is optional, but it spaces your boards off the back of the enclosure and makes them easy to add and remove as needed.

For attaching components to DIN rails

I used these on the enclosure to protect sensitive electronics from vibrations.

Note: This sensor failed after a few days of exposure to diesel fuel (despite claiming it was compatible). I'm still searching for a more robust sensor for measuring fuel pressure.

Diesel fuel fittings often use banjo thru-hole style fittings. This adapter lets you add a pressure sensor to your banjo fitting. Check what types of fittings your vehicle uses and buy the appropriate adapter.

A pressure snubber protects your pressure sensor from pressure spikes, and gives more accurate readings by lowering noise. This is useful in liquid systems, but isn't needed when measuring air pressure.