• Construction

    Sukasa09/30/2016 at 02:58 0 comments

    This build went through a few revisions over time and modifications, with input from several members of the makerspace and is still subject to occasional tweaks and modifications even now - for example, the light used to be switched with the rest of the unit, but now has its own switch.

    The base of the system is based around a duct booster fan, meant to help in residential HVAC. We repurposed it as the main extraction fan in this system (it is directed out a window), and opted to use small PC fans* at each stand for a little extra suck. Flexible dryer hose connects each stand (made of a wooden base with acrylic extension) to the ducting in the upper structure.

    The lighting is made up of an LED-lit lighting board. This used to be a cheap marketing light panel, kind of like you'd see at an electronics store. We just took the SONY banner off it and turned it over as it makes a great, even light source. It's powered from a decent 12v 5A supply that's zap-strapped to the superstructure, and that is fed from the household wall switch below the fan switch box.

    The fan power is produced from a 120->-5/5/12V supply inside the main switch box. A decorative grill from an old PC case was dremelled and bent to form a safety grille that keeps fingers out of the somewhat more hazardous parts of the box. This supply is fed from an Allen-Bradley 2-position switch that was donated as part of a larger set of ABB parts. This switch also controls power up to the booster fan (the fan uses a low enough amount of power that we're well within the switch's current interruption rating).

    Power for the fans is run through ethernet cables, which are all soldered to a small protoboard that is mounted inside the upper ductwork. This runs down to the fans with 4 conductors each for the +12v and Gnd lines.

    Since we needed specialized fittings to connect the dryer hose to the ductwork, and also to the acrylic, we just 3D printed what we needed. OpenSCAD to the rescue here; it produced an excellent set of designs for all of the prints we needed on the job

    * I know that's not the official name, but it's descriptive enough for a small 12v fan of that form factor