Building a cellular tracker: Part 8 – the Case

As described earlier my cellular tracker did not only have a couple of electrical and software challenges – running autonomously in the wild also would require a safe housing for it, something that can handle rain, high and low temperatures, carry a solar-panel etc.

Below you can see the different cases i tested out – in fact you can see two families of cases – one known as “Otterbox“, the other with the easy mountable screws on the edges are from Adafruit and can be ordered in a small and a large version. The otterboxes can be ordered in three different sizes – also in the Adafruit store (the one in the picture below is medium on the right and small on the left). Then there is the “project case” on the front left side which can be found at Sparkfun and their distributors.

The latter is a very nice and handy enclosure, but it just did not fit into my requirements because it is not made for outside applications. But if you need a non-waterproof solution i can recommend it.

The Otterboxes (just saw that adafruit does not sell them anymore for whatever reason) are really awesome – i take every promise they make regarding durability for granted, these are really absolutely robust and professional boxes, their closing mechanism is very handy and stable in the same time – you don’t need a single screw to fix them very tight. For my purpose a critical disadvantage (besides the price) was the fact that they are shaped in a special way and that the plastic is not perfectly translucent. As my sensor would have to measure light from the inside this was quite an issue. The other problem i faced is mounting a solar panel on it. If you want to do this a “standard” size and flat surface is critical to use the maximum space for your solar-cell. As the surface of the Otterboxes is not flat they were out (in the picture below the one in the middle is the mid-sized Otterbox with a Solar-Panel mounted on the outside). But i would really recommend them if you are looking for the most robust and in a sense beautiful housing for your project.

At the end i chose the Adafruit system, both the bigger and the medium box are in use at the moment. For both versions you can find solar-panels that fit very well into the box, for the small one i used the tiny 0.5w panel from seedstudio that comes in very cheap. The bigger one can easily host this 2w panel from Voltaic Systems for instance that can be bought at Adafruits shop as well. These cases are also of a very nice quality, i like the big plastic screws that can be screwed in with a knife or even with your fingers. They are robust enough for outdoor use and can stand a lot of rain and snow without letting too many of the bad H2O molecule guys in.

Ah – and not to forget – the guy in the middle. Yes, i was inspired by the GPRS-tracker from Seed that has been sold in a similar enclosure in the past (couldn’t find a picture anymore). I really liked the idea to put the electronics simply into this glass-enclosure originally made to conserve food and marmelade. Unfortunately i cannot recommend it because it is not safe in heavy rain. I think the reason is that the whole concept is made for stuff that get’s heated up and the conserved which creates under-pressure inside the enclosure while cooling down. As i do not plan to do something like this with my Arduino the rubber between cup and case could never really get under pressure, therefore this case would not get tight enough.