I recently started playing with Arduino in order to do several projects, including:
A system which will measure some characteristics of the indoor air and could alert me if something goes wrong (for instance if the percentage of CH4 goes beyond a threshold).
A system I can bring with me on a walk which will measure the pollution and other characteristics of the air outdoors.
While the quantity and the diversity of the sensors for such projects, as well as the ease of use is mind blowing, I'm blocked at one aspect: the casing. Both of the projects require to put the electronics within a plastic case with:
Enough space for not only Arduino, but also the sensors. Some, such as MQ2/MQ5, can be quite large.
Holes for air flow, which are large enough to let small particles, but small enough to keep insects and large dust out of the electronics.
A hole for an USB cable and possibly a hole for the LED.
Unfortunately, the popular sites selling Arduino-related stuff have practically nothing when it comes to the cases. In most cases, the choice is limited to (1) the enclosures for Arduino itself (or other boards), with no holes in them and (2) the multicolored modular systems which look like LEGO bricks.
Outside Arduino-related sites, the only idea I have is to buy somewhere an old smoke detector, throw away the electronics and put Arduino and the sensors inside. For now, most smoke detectors I've seen seem too small for the task, and have to be modified in order to accommodate the USB cable.
Am I missing something? How other people do when they need an enclosure which fits Arduino and sensors and doesn't look geeky?