This is derived from the great case design by Egil.
Updated Dec 16th: Increased clearance on the button inserts, and decreased height of tact switch standoffs in top. Buttons are all decreased by .4mm diameter - and should fit with no filing or sanding necessary straight from printer (at least they do from my printer) - if you need larger clearance you can alter it in the SCAD file by editing the variable "buttonclearance = 0.2;" Clearance between slider switches and case is not changed as this close fit is necessary to keep the extensions from bending.
Original Post: When I printed one I noticed that the PCB holes did not line up with the version of the PCB I received in Dec 2015 from Banggood. - everything fits except the PCB mounting holes have moved 1mm towards the edge in the X dimension, and the slider switches appear the have moved .5mm to the left... Above pictures show original hole misalignment with my PCB- the files in this thing have the corrected hole locations as does the source SCAD.
If your PCB has the mounting holes centered 5MM from the edges of the PCB (nor the corner) this is the correct version for you.
Anyway now the PCB mounting holes appear to be symetrical from the corners of the PCB - whereas before they must have been about 6MM from the edge in the X (left, right) dimensions.
A few other changes are the addition of the front USB port as I want to connect a lithium ion battery charger PCB ($1.5 on ebay) to the USB VBUS pin from this port to charge an internal li-ion instead of using 9V battery. Bangood also sells a stepup dc-dc converter designed for the DSO138 that takes 3.3-5V and boosts it to 9V.
The battery charger PCB I choose also has under/over voltage protection built in which is critical to protect the battery if your battery doesn't come with a PCB attached.
The electronics look like they will all fit in the 9V battery compartment, just barely ;) - although it is fairly easy to increase the size because the source is available in SCAD if you wanted a larger battery compartment.
The countersink on the bottom cover was not wide/deep enough for my 3mm screws so I increased the width/depth some. The below screws now fit perfectly flush. The 10MM screws allow for 2.5MM thread engagement - if you want more choose the 12MM long ones, but 2.5mm seems to be enough as they don't have to bear any real force.
I also increased the hole size the threads engage into - now the screws should self thread into the plastic without threading necessary.
The screws I used are: Flat Socket Head Screws A2 SS - 3M x .5 x 10MM
By - http://www.easybotics.com/
And - http://hilo90mhz.com/