A small 15x15x15mm switch for fischertechnik as a complement to the classic mini switch. Needs a 12.8 x 6.5 x 5.8 microswitch with metal actuator, find them in old computer mice or order them cheap. The design is not perfect, it has a bit more resistance than the original and the contacts are a bit prickly, but they do work if done right.
Print with high quality (.12 mm), no infill, no supports. I used PLA, not sure if the spring part will work as well with other materials.
Needs quite exact prints and thorough sanding particularly of two inside faces (see image). See other images for assembly, the basic steps are:
- Cut the metal actuator so that it does not protrude beyond the dimensions of the switch when pressed down.
- Gently bend the three bottom contacts 90° to the front. Watch out for the correct orientation, or the markings will be wrong. Ideally, the contacts will not point straight to the front bit with a slight bulge that will improve the contact with the plug later.
- If the contacts extend to the front beyond the dimensions of the switch, shorten them. Sand the cuts a little diagonally to make it easier for the plug to slide in later.
- Slightly bend the actuators a little upwards. This is not really necessary, but will make the action more homogeneous over the full length of the action.
- Insert switches, press down until flush with the upper edge of the bottom part.
- Cut a 12.5 mm piece from the spring part and insert it into the printed actuator part's slot.
- Carefully insert into the bottom part, there is another slot at the bottom, try to insert the spring's other end there.
- Apply top part and test function. Watch out for the markings, the layout is different from the ft mini switches, the common contact is not in the middle.
- If it works, glue top part to bottom part. If it doesn't, well, I told you, your prints need to be pretty exact... ;-)
juh
