Renewable Energy Monitor

There's a widening range of enclosures for Arduinos:

• Flanged aluminium box
• http://www.adafruit.com/index.php?cPath=17&main_page=product_info&products_id=271
• Clear enclosure
• http://store.arduino.cc/eu/index.php?main_page=product_info&cPath=11_15&products_id=79
• Sparkfun's £4.95 crib that holds an Arduino and an Ethershield without an enclosure.

But most enclosures for Arduinos are a tad expensive - from £8.10 ($12) to $16 plus overseas shipping - and I've not been so impressed with the two that I've bought. The manufacture was either:

• poor quality, or
• the designs not capable of doing what they were alleged able to do, such as en-case an Arduino and a full-height Ethernet shield. Or,
• they were too inflexible for the range of shields that I want to box in with the Arduino.

That latter problem is hardly the fault of the designers though: I'm using two different Ethernet shields with their RJ45 sockets located in radically different places. This was the problem I found with the otherwise excellent Sparkfun/Technorobotsonline Arduino plus Ethernet Shield case.

Whatever the cause, the outcome is that it's not always possible to produce customer-facing quality demonstration kit.

So I made my own enclosure.

Hopefully many places sell the Type 3 top-hat enclosure that I found in Maplin UK (Maplin product code YN37) for £2.89. They are possibly made by Hammond and have an internal code stamp that reads: RX1005

It's dimensions - in millimetres - are:

Long base: 115.35 Indented base length: 83.67

Broadest width: 63.90 Indented base width: 57.40

Height: 45.79

They are a comfortable fit for an Arduino and Ethernet shield stack, and undoubtedly for many other shields too.

Like all 'top'hat' or 'box and base' designs, the body of the enclosure is flanged to fit on to a base that acts as a the mounting plate for fixing the enclosure to a solid surface.

One method of mounting the Arduino on the base is to use double-sided sticky pads. I opted to epoxy four washer and nut combinations to the base in locations beneath the Arduinos' mounting holes.

I offset the mounting points to bring the Arduino's USB socket and any Ethernet Shield's RJ45 socket up against the inside wall at one end of the enclosure.

Exactly where you mount the washer/nut combinations is up to you but you can use Adafruit's Arduino dimensional drawings to get the mounting bolt locations relative to each other.

Where you position the group of mount bolts in the case is up to you - just bear in mind that the Arduino's USB socket stands a few millimetres more proud than does the RJ45 socket on a standard Ethernet shield. So you can either cut the USB hole large enough to let the USB socket through the enclosure wall and bring the RJ45 socket up against the wall. Or tolerate having the RJ45 a few millimetres inside the enclosure body, as I did.

The photograph below better illustrates the gap between the lower edge of the Ethernet shield's RJ45 connector and the nd-wall of the Type 3 box's end wall. The gap is larger than it needs to be in this example because I cut the lower wall about 1mm lower than it really needed to be.

The gap is more an issue of perfectionist pride than anything, though the smaller the gaps the fewer insects and perhaps even dust will find their way into the enclosure.

Here's how the end-wall looks when viewed end-on. Not too bad. (I'll sort a better photograph in time):

The below image was sized at exactly the same dimensions as the box base, so with luck, you can print it out and use as a template for the mounting bolt positions. With luck…

I've supplied the measurements from the left end of the base below:

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In the end of the enclosure body, I created holes for:

• Arduino USB socket
• Ethernet Shield RJ4 socket
• 3 off 5.5mm holes for tail grommets for the power supply cable and two separate sensor cables.

I did not cut a hole for the Arduino's built in power supply jack because I supply 5v to my sensors and the Arduino Unos I am using are unstable if 5v is supplied via the voltage regulator behind the standard power supply jack. Instead, I wire the power cable directly into the Arduino's 5V and Gnd connectors.

Other folks have also tackled this problem, with

• very stylish results, and
• Options for designing your own custom enclosure, and finally,
• here's a great, three-part review of alternative Arduino enclosures.