What is it?

A plastic enclosure for small electronic projects, with a PCB to mount your components. It is intended to house a development board such as Adafruit Feather, NodeMCU, or Arduino Nano, and a small number of additional components.

It also includes a rubber grommet for routing the wires outside the enclosure - for example, for connecting a power supply, extra sensors, or other electronics .

The box itself is waterproof; the grommet is not waterproof, but provides limited protection from dust and splashes (see details below).

Why did you make it?

I had difficulty finding enclosures for my projects. Boxes themselves are easy to find, but if you also want an easy way of mounting your electronics inside, your choices become very limited. If in addition you are unwilling to pay more than $10 per enclosure, then essentially your only choice is Adafruit's Mint Tin with matching perfboard, which is not adequate for many of my projects. So I set out to make my own.

What is included?

• The ABS box, with clear plastic lid
• Printed Circuit Board (PCB) fitting inside the box
• Mounting screws (#4-40)
• Rubber grommet for routing cables(1/4" inner diameter)
• (optional) JST PH 4-pin or Grove connectors

Dimensions

Box outside dimensions: 85x58x33 mm (not including mounting flaps)

Mounting holes: 3.2mm diameter, spaced 96 mm apart

Inside dimensions: (approximate) 77x52 mm

Inside height (from top of PCB to the lid): 22mm

PCB details

The PCB is designed to perfectly fit inside the enclosure. It is designed for easy mounting of a board such as Arduino Nano or Adafruit Feather, or any other board which has one row of pins (up to 16) on each side, with two sides spaced 0.6"-1.0" apart. This includes Adafruit Feather, Arduino Nano, Arduino MKR, NodeMCU, and many other boards. The boards can be directly soldered to the PCB, or, more commonly, plugged into female headers soldered to PCB (headers are not included). For each pin, the PCB provides a group of 3 interconnected holes, for easy connections.

The PCB also contains:

• three power/ground rails (they are not connected to any pin - you have to make your own connections)
• place for soldering two 4-pin 2mm pitch connectors, such as JST PH or Grove (connectors can be be added to as an option)
• a small prototyping area for adding other components

Outside connections

To connect your project to the outside, you can use the included rubber wire grommet, cutting it open and drilling a hole in the enclosure as detailed below. It is not waterproof, but does provide limited protection from dust and splashes; you can add silicone sealant to make it more weatherproof.

You can also use a PG-7 cable gland (not included), which allows you to make a waterproof connection. However, cable gland is less convenient, as you can only run wires up to 6mm diameter through it; if you have a wire with a connector (e.g. USB cable or JST PH connector), you would need to cut it, run it through the gland, and then resolder. With cut grommet, you can use wires with connectors without cutting them.

Installing the grommet

To install the grommet and route wire through it, follow these steps:

• mark the hole position on the side of the enclosure. The hole center should be 7 mm below the lip of the box
• use small (1/16") drill bit to drill the pilot hole.
• use step drill bit to drill out the hole to 7/16" (or 12mm if you have metric bits)
• use diagonal cutters to open up the hole as shown in the photos
• drill the hole for wires in the center rubber grommet, to match wire diameter (up to 1/4")
• cut the grommet open using scissors or flush cutters
• route the wires through the grommet and install the grommet in the hole, with the cut pointing down