An enclosure for the basic 4 button PWM generator module. This is a re-mix of the design by fxch (https://www.thingiverse.com/thing:3215646), as I wanted access to all the pins but didn't need the USB/UART module. This design also fixes the following issues:

1) The buttons on the original simply don't work, they bottom out on the switch body before actuating the switch. They are also poorly retained in the case and fall out easily. All four buttons are now printed as a single part, making assembly easier and making it impossible for them to fall out.
2) The buttons were not all correctly centred over the switches (minor issue)
3) The cut out for the LCD screen had extremely thin (1 or 2 layer) bezels that were easy to break just removing the case from the print bed. The cut out was also not well centred on the LCD. This has a significantly deeper bezel with a nice 45 degree chamfer.
4) The slot for the PWM output pins was not correctly centred, there was not enough room to put a jumper wire on the top pin.
5) The back of the case was retained only by friction (or glue). Clips/tabs have been added to ensure it snaps securely in place.

It's possible that some of these issues are due to slight changes in the module design.

The PWM module is designed to be a snug fit in the case, but the edges of the PCB can be very roughly cut. If it's a tight fit, simply remove the rough edges of the PCB with sandpaper or a fine file. When soldering header pins to the PCB take care to get them vertical, to ensure the are well centred in the front panel access slots. Solder a single pin on each header strip first and then check the PCB in the case for alignment.