Housing for homemade desktop thermometer and hygrometer

I had this piece of homemade electronics at home for years, always intending to make a housing for it when I have some time. I had the commercial empty housing already, but never could get myself to drilling, dremel-ing and filing the rectangular LCD window into it. I am glad I waited until the world (and myself) has discovered 3D printing.

This housing is made from scratch with FreeCad, one part with the "part" workbench, the other one with the "part design" workbench.

The two pieces fit very well together, the guides on the upper and lower edge enforce a tight fit. Using only two screws instead of one in every corner turned out to leave some very tiny gaps at the upper and lower end of the long edges, but for practical use I am fairly happy with the results.

All you need in addition are two pieces of M3x14 screws. The domes in the front side are made in a way that M3 screws are self-cutting into the plastics. That worked very well for me with PETG material. I would guess that PLA might be breaking if you try to force the screws in.

For those that are interested in electronics: I made this design to challenge myself on how much software functionality I could fit into 1024 Bytes (!) of Flash memory on the ATtiny13. I wrote the LCD driver for an old Ericsson SH888 mobile phone display, the driver for the thermometer/hygrometer sensor and some clever mixture of hardware and software combination to generate the negative LCD contrast voltage. Also I used the internal ADC to read the battery voltage, convert all data into decimal readings and put them on the LCD. Furthermore I wrote a highly optimized power safe software, which lets this piece of equipment run for many months on three rechargeable AAA batteries, despite the fact that the ATtiny13 is by far not the most power saving processor that you can get today.
All that did fit into 1024 Bytes, but there was not a lot of memory left in the end ;-)

Print instructions

Category: Electronics Print Settings

Printer Brand: Prusa

Printer: I3 MK3S

Rafts: Doesn't Matter

Supports: No

Resolution: 0,15mm

Infill: 100%

Filament: Prusament PETG PETG Orange