Wrap Up

We're done coding and here's the final code in full:

baseWidth=15;hingeLength=30;baseThickness=3;pivotRadius=5;pinRadius=2;pinTaper=0.25;mountingHoleRadius=1.5;mountingHoleCount=3;mountingHoleEdgeOffset=4;clearance=0.2;tiny=0.005;
// calculated valueshingeHalfExtrudeLength=hingeLength/2-clearance/2;mountingHoleMoveIncrement=(hingeLength-2*mountingHoleEdgeOffset)/  (mountingHoleCount-1);
// modulesmodule hingeBaseProfile() {  translate([pivotRadius,0,0]){    square([baseWidth,baseThickness]);  }}
module hingeBodyHalf() {  difference() {    union() {      linear_extrude(hingeHalfExtrudeLength){        offset(1)offset(-2)offset(1){          translate([0,pivotRadius,0]){            circle(pivotRadius);          }          square([pivotRadius,pivotRadius]);          hingeBaseProfile();        }      }      linear_extrude(hingeLength){        offset(1)offset(-1)hingeBaseProfile();      }    }    plateHoles();  }}
module pin(rotateY, radiusOffset) {  translate([0,pivotRadius,hingeHalfExtrudeLength+tiny]){    rotate([0,rotateY,0]) {      cylinder(        h=hingeLength/2+clearance/2,        r1=pinRadius+radiusOffset,        r2=pinRadius+pinTaper+radiusOffset      );    }  }}
module hingeHalfFemale() {  difference() {    hingeBodyHalf();    pin(rotateY=180, radiusOffset=clearance);  }}
module hingeHalfMale() {  translate([0,0,hingeLength]) {    rotate([0,180,0]) {      hingeBodyHalf();      pin(rotateY=0, radiusOffset=0);    }  }}
module plateHoles() {  for(i=[0:mountingHoleCount-1]){    translate([      baseWidth/2+pivotRadius,      -baseThickness,      i*mountingHoleMoveIncrement+mountingHoleEdgeOffset    ]){      rotate([-90,0,0]){        cylinder(r=mountingHoleRadius,h=baseThickness*4);      }    }  }}
// using high-level moduleshingeHalfFemale();hingeHalfMale();

Live Demo

Lets reflect on what you've achieved

Parametric

By diligently using variables instead of hardcoding values, you have create some code that is not only much easier to read and re-use, but it's now parametric by default, which means we can change the value of the variables and the model adjusts Here are some variations:

Composed of many small well named modules

By keeping modules small and making lots of them you've also done a great job of making the code easier to read.

Included fillets

By taking extra steps to add fillets to you part, you've made the part stronger and already puts you head and shoulders above many OpenSCAD designs.

Print in place

You've already tackled clearances for getting parts to fit together or print-in-place.

Well done.