Adjustable Step Up And Step Down Voltage DC Power Supply Box

thingiverse

This is a power supply I built using inexpensive parts available on e-bay. I find I need a variety of voltages for powering fans and other devices. Features include: Independent adjustable step up and step down voltage regulators. The step down supply source is switchable between the input source or the step up supply output Two voltmeters to monitor input and output voltages. One meter can be switched to either input source or the step down supply output while the other continuously monitors the step up supply output Four panel mount 5.5 x 2.1mm DC power jacks (one source in, one step up output, one step down output, and one source in pass through output. A bill of materials is included along with a schematic of the circuits for assembly. Total cost for parts is < $35USD if you have to purchase everything. Although not cost effective vs. buying separate supplies, it does tuck in nicely behind my Replicator 2X and is very functional. Best of all it's 3D printed! The design files provided are Cubify Design from 3D Systems (formerly Alibre). I have a heavy duty 12V supply I power this supply box with. I step up the voltage to 24V for some fans I use, and I step down the voltage to 7-8V for fans that need driven less than full power, or pass through the 12V supply to use directly. The circuit connections are straight forward but there are 20 wires to cut and solder, 16 screws to drive, and two switches to mount - plan on a couple hours for assembly. Instructions See the attached power_supply_BOM.pdf file for a bill of materials and the items to search and purchase on e-bay. You can search directly on the BOM description. I've also provided a sample device e-bay item number, although over time these will become obsolete. The StepUpDwnSchematic.pdf file captures a schematic of the circuits to show you how to wire the components. I cut a protoboard down to size and drilled two 3mm holes for mounting on 0.600" centers. A picture is provided. This board is used as a wiring junction for the source in V+, the source in V-, and the step up regulator supply V+ net. There are seven source in V+ wires, four source in V- wires, and three step up regulator V+ wire connections. The others nets have only one or two wires, with the regulator output nets having the two wires. I soldered the second wire directly to the regulator output pad w/o issue. Note I soldered the wires to the bottom of the regulator pads as this helps keep the wiring below the regulators. The cut out on the box lid allows access to the resistor pots to adjust the regulator voltages. Be sure the regulator boards are oriented correctly so the resistor pots are accessible with the box lid installed. Look at the supply box top labels to determine which voltage regulator goes where, what each voltmeter is, and how to orient the switches correctly. The box has labels for what each 2.1mm DC jack is. Coupled with the schematic the circuit layout will become apparent. I ensured there was plenty of room around the DC jacks, thus you can easily modify the holes for different DC jacks if you want w/o likely requiring other rework. I've printed these with Makerware standard settings with ABS successfully. 10% infill, 2 shells, 0.20mm layer height. I used this project to learn the CAD software as I am new to 3D printing. There are likely improvements that can be made, yet I've found the design very useful and thought it was worth sharing.