Skip to content

Instantly share code, notes, and snippets.

@rocktronica
Last active Nov 21, 2022
Embed
What would you like to do?
// Size 4-40
screwDiameter = 2.8;
screwHeadDiameter = 5.5;
screwHeadHeight = 2.3;
insertDiameter = 4;
insertThreadedDiameter = 4.45;
insertHeight = 3.5;
standardPotShaftTopHeight = 8;
standardPotShaftTopDiameter = 6;
standardFlattedDepth = standardPotShaftTopDiameter - 4.5;
minimumKnobHeightFromShaft = 2;
minimumKnobHeight = standardPotShaftTopHeight + minimumKnobHeightFromShaft;
potKnobDefaultShimCount = 3;
module pot_knob(
knobDiameter = 15,
knobHeight = minimumKnobHeight,
knobColor = [.1,.1,.1,1],
innerColor = undef,
shaftDiameter = standardPotShaftTopDiameter,
shaftHeight = standardPotShaftTopHeight,
showChamfer = true,
markerHeight = 1,
markerWidth = 2,
markerRotation = 0,
markerColor = "white",
showMarker = true,
invertMarker = false,
shimWidth = 1,
shimLength = .5,
shimCount = potKnobDefaultShimCount,
tightenerDiameter = 0,
recessHeight = 0,
recessDiameter = 0,
flatted = false,
flatDepth = standardFlattedDepth,
flatTolerance = undef,
$fn = 100,
debug = false,
tolerance = .25,
previewGutter = .1
) {
useSkirt = recessHeight > 0 && recessDiameter > 0;
recessHeight = useSkirt ? recessHeight : 0;
recessDiameter = useSkirt ? recessDiameter : 0;
shaftHeight = useSkirt ? shaftHeight + recessHeight : shaftHeight;
innerColor = innerColor == undef
? knobColor
: innerColor;
module standard_pot_flat_cutout(
rotation = -markerRotation,
depth = flatDepth - (flatTolerance == undef ? tolerance : flatTolerance)
) {
width = shaftDiameter + previewGutter * 2;
length = shaftDiameter; // arbitrary
rotate([0, 0, rotation]) {
translate([
width / -2,
-length - (shaftDiameter + tolerance * 2) / 2 + depth,
-previewGutter
]) {
cube([width, length, shaftHeight + previewGutter * 2]);
}
}
}
module outer() {
cylinder(
d = knobDiameter,
h = knobHeight
);
}
module shims() {
offset = shimCount == 1
? 0
: (360 / shimCount / 2) - markerRotation;
for (i = [0 : shimCount]) {
rotate([0, 0, offset + 360 * (i / shimCount)]) {
translate(
[(shimWidth / -2),
shaftDiameter / 2 - shimLength + tolerance,
previewGutter * -2
]) {
cube([
shimWidth,
shimLength * 2,
shaftHeight + previewGutter * 3
]);
}
}
}
}
module inner() {
difference() {
translate([0, 0, -previewGutter]) {
cylinder(
d = shaftDiameter + tolerance * 2,
h = shaftHeight + previewGutter
);
}
if (shimCount > 0) {
shims();
}
if (flatted) {
standard_pot_flat_cutout();
}
} // difference
}
module recess() {
translate([0, 0, -previewGutter]) {
cylinder(
d = recessDiameter + tolerance * 2,
h = recessHeight + previewGutter
);
}
}
module marker() {
z = invertMarker
? knobHeight - markerHeight
: knobHeight;
height = invertMarker
? markerHeight + previewGutter
: markerHeight;
rotate([0, 0, markerRotation * -1]) {
translate([(markerWidth / -2), 0, z]) {
cube([markerWidth, knobDiameter / 2, height]);
}
}
}
module shaft_chamfer() {
chamferDiameter = shaftDiameter + 3;
chamferHeight = chamferDiameter / 2;
translate([0, 0, recessHeight - previewGutter]) {
cylinder(
d1 = chamferDiameter,
d2 = 0,
h = chamferHeight + previewGutter
);
}
}
module tightener_cutout() {
wallDepth = (knobDiameter - shaftDiameter) / 2;
headCavityDepth = max(screwHeadHeight, wallDepth - insertHeight);
minimumBaseBeneathHeadDepth = 2;
translate([0, 0, recessHeight + shaftHeight / 2])
rotate([90, 0, 0]) {
cylinder(
d = tightenerDiameter,
h = knobDiameter
);
if (wallDepth >= headCavityDepth + minimumBaseBeneathHeadDepth) {
translate([0, 0, knobDiameter / 2 - headCavityDepth]) {
cylinder(
d = screwHeadDiameter + tolerance * 2,
h = headCavityDepth + previewGutter
);
}
}
}
}
intersection() {
difference() {
color(knobColor) outer();
color(innerColor) {
inner();
if (showChamfer) {
shaft_chamfer();
}
recess();
if (showMarker && invertMarker) {
marker();
}
if (tightenerDiameter > 0) {
tightener_cutout();
}
}
} // difference
if (debug) {
translate([
knobDiameter / -2 - previewGutter,
knobDiameter / -2 - previewGutter,
-previewGutter
]) {
cube([
knobDiameter / 2 + previewGutter,
knobDiameter + previewGutter * 2,
knobHeight + previewGutter * 2
]);
}
}
}
if (showMarker && !invertMarker) {
color(markerColor) {
marker();
}
}
}
@rocktronica
Copy link
Author

rocktronica commented Oct 30, 2019

Designing Potentiometer Knobs

From the blog post Designing Potentiometer Knobs

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment