Parametric Switch Panel
by CodeCreations, published
Update 9/15/12: v0.69 includes mounting holes, trace output, snap-on Prusa Mendel brackets, and "debug" methods.
This is a fully parametric, fully printable switch panel. Currently 26 parameters can be tweaked to change everything from the size of number of switches and panel to the number of throws and throw angle. By adding just a bit of old network cable wire and piece of a brass fastener, the switches can be wired in a number of different configurations, including SPST, SPDT, SPTT. (I'll be adding DPST, DPDT, DPTT configurations next.)
Most of these tests I've printed have two switches, but it's very easy to render only one or even more than two. For example, for six switches arranged in two rows of three, just set the switches parameter to [3,2].
The code is fully commented, and all the parameters are described in the code file.
This is a work in progress, but I wanted to get it out there to hopefully start generating feedback.
Currently the parameters include number of positions, throw angle (from perpendicular), number and layout of switches, distance apart, extra panel size, hole clearance, panel thickness, paddle thickness/width/length/rounding radius, lever profile, extra lever extension, dedent height, fulcrum diameter, fulcrum support radial and lateral thickness, bare and insulated wire diameters, and several parameters that define how the contact plate is attached. The latest update also includes several parameters for mounting holes and brackets.
If you want a simple set of two SPST or SPDT switches that will pivot on a spare piece of 3mm filament, then just print the STL. Otherwise...
Choose some values in the "User-defined values" section, render, and print. Experiment to get a smooth-acting switch -- several factors affect the action, including the thickness of the panel, the fulcrum supports, the dedent height, and others. Insert the levers through the front of the panel using the extra width provided at the center of the holes. Insert a piece of filament or a screw to allow the lever to pivot.
The wire channels are experimental. They're intended to provide space to route wires for the switch. The "Plate Contact" seems to work okay, though. To use it, fasten a piece of metal to the end of the lever using super-glue (CA glue) or a screw. (I use a piece cut from a common brass fastener, like the ones shown here: http://amzn.com/B004LWSFAK .)
Feed bare wires through the holes in the fulcrum structure, bend the wires around, and twist it back onto itself so that the metal contact bridges the gap when the switch is activated.
You can also attach one of the wires to the center tab instead.
Take a look at the photos of the black switch panel with the yellow switches. This is wired as a simple on/off switch with some old CAT-5 network cable, and the wires are held in place with globs of hot glue. The three sets of +V/GND go off to the right and are held in place with the mounting bracket. Each set goes off to one device that controlled by one of the switches.
The GND (blue) wires from these sets are bunched up and go to the negative or GND terminal of the voltage supply. The white wires travel across the top of the switches and attach to the bottom left of each switch. (This is the "on" position.) Three more white wires go from the bottom right of each switch, around the bottom of the switches, and are bunched together where they connect to the +V terminal of the voltage supply.
- Be sure the metal plates don't get coated with glue if you glue them on. CA glue is not conductive.
- Use a bit of wire in the glue-up to reinforce it. Drill tiny holes in the metal plates for the wire. Put a drop of glue on the end of the lever, then put the wire in through the glue and turn it a few times to spread the blue inside. Then remove the wire, place the metal plate, and re-insert the wire. Cut off the excess after the glue has dried.