I see this is an old post and I have been looking for this information as well as it pertains to the Bela sold during 2022. I found one mention on the Bela website for the Bela and Bela Mini board dimensions. 87mm L x 54mm W x 27mm H was posted for the Bela but no mention of the mounting hole dimensions. The Bela Mini was 56mm x 35mm x 21mm. The Mini has no mounting holes.
I measured my Bela board that came with the starter Kit with my digital calipers. It measured:
86.4mm L x 54.83mm W edge-to-edge which is very close to the Bela website's published dimensions.
The mounting hole diameters measure ~3.0mm. The lengthwise mounting hole center-to-center dimensions measure ~66.1mm. The mounting hole width dimensions are wider at the USB-B/Ethernet connector end than the SD memory card end, 48.2mm vs. 42mm, and are centered on the centerline of the Bela PCB.
I'll be using these measurements to create a mounting platform for my Bela and its Cape and will report back with updates.
