This is a modular rack system to hold four Raspberry Pi 3s along with a network switch, USB power hub, and a fan. Builds as a set of modules, which clip together to form a full system.
The devices I used are:
- Netgear ProSAFE 5-port gigabit switch - UK part number GS105UK
- RAVPower 60W mains charger - UK part number UK RP-PC028(B)
- USB 5V-powered 80mm x 80mm x 25mm fan (sourced through Ebay)
and of course a bunch of Raspberry Pis!
To avoid excessive height, I used a right-angled figure-8 power connector for the USB power block.
BTW the video in the gallery is one of Vi Hart's excellent explanations why Tau is better than Pi. Go follow her!
Used Wanhao "fast" print setting (0.15mm layer depth, 0.5mm line width) - total about 48 hours of print time for all components.
Used brim to prevent corners lifting during print; the 4-Pi module is particularly susceptible so watch out for that. Enclosing the printer helps here to reduce temperature fluctuations and draughts.
Supports are used mostly for the "beams" at the back of the system. Mostly the supports are easily removed; poke through the diamond wall holes to break off the support panels internal to the modules. Grid support type gave most consistent results.
Additional - the fan retaining beam posts are weak if oriented flat on the build plate, hence what looks like an odd orientation for it in the .stl presented here (which need a little support as a result). Take a look at dbgeorge's make for a remix of that piece with a neat alternative solution to the post strength problem (and a nice Raspberry front panel!).
Designed in OpenSCAD, the main source is of course the cr.scad file. This file can generate all of the STL modules - refer to the comments at the top of that file to see how to use it, but essentially you render the same design separately for each module by changing a variable assignment towards the top of the file.
The name plate is presented here as two separate prints (the plate, and the words), which can be glued together - they have sufficient tolerance that they fit neatly. However there is also a variant for use with multi-extruder printers that can be generated without the tolerance. My printer has a single extruder, so printing like this means all the fun of swapping filament mid-layer - hence the depth of the words is reduced to minimise the number of filament swaps.
"Two Tau"? Well, pi is wrong so here I have two tau's worth of Raspberry Pis.
Modifying the name plate is left as an exercise for those (wrong :) ) people who prefer to use the half-a-circle constant...