Expansion Module Area Dimensions/Etc

I’ve had my devterm for a few days now, and I’m already starting to think of possibilities in place of the thermal printer. In keeping with the modular spirit, I’m trying to veer away from my normal Dremel/plastic cement ways, and dip my toes into 3d modeling and printing; however, I can’t seem to find any documentation of the internal dimensions of the unit online. I’m not above breaking out my calipers and measuring, but before I go to the trouble does anyone know if there is any documentation available on the case/physical dimensions inside?

For this first stab at module making I plan on creating essentially a PLA slab with holes to fit in place of the existing printer; from there I’ll be able to mount whatever I want on the slab (delidded RTL-SDR, ethernet adapter with male RJ45 on retractable spool, RS232 on retractable spool, etc) and use the existing lid/layout of the devterm.

To that end, is there any particular place where module creators have started to gather? My apologies for the rambling post, I’m new to this community and excited about the possibilities


I can’t say the dimensions but you can download OBJ files for all of the parts that you could use as a starting point to modify. They are available on the “shop” page.

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perfect, thanks, that’s exactly what I was looking for! maybe if I’m feeling really industrious one of these days I can make a measurements schematic

Messy workbench aside, here’s my quick and dirty measurements for anyone interested

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Do you have any plans for how to connect a custom module? It doesn’t seem like there is an easy way to interface them without a custom EXT board as well, unless you just maybe desolder a USB port and wire up an internal jack.

great minds think alike; that was pretty much my plan. I’m (for now) not knowledgeable enough to design my own expansion, so it’s about the only option I see. Luckily on the EXT board there’s plenty of space around the USB pin headers, so I’m planning on soldering to one of those, then coming off to Dupont pins or similar so I can take out “module shelf” at will. I’m then thinking of capping off the USB port with a 3d printed cover so I don’t accidentally plug something in there (not sure what would happen, but I’m not keen to find out).

As it turns out, for my purposes, a bit of soldering is going to be necessary anyway; the RTL-SDR stick will only fit neatly if the male USB plug is removed (hello, bench grinder, old friend…)

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I have 90 degree USB adapters might make the sdr less combersome

is it something like the reverse version of the cable below? I’d love to avoid permanently modifying one of my dongles if I can, but as you can see clearance-wise for the SMA connector to be the only thing that sticks out the USB plug has to go. I’ve thought about putting the SDR in diagonally, but I’d really like to have the connector handy for quick antenna changes (without all the signal loss/etc from an extension mounted in the body, another option I’ve considered

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I was thinking I would like to slot a HackRF One in there. The board will def fit (width), and I can 3D print something to cover the top half that will be sticking out. But my main issue is the same as all of you - how do I get USB into the expansion space. If Clockwork sold an expansion board that exposed usb in there I would be the first in line.

How did you all get on with the RTL-SDR?

To be honest, I haven’t really used mine since I got it in and was able to run a few tests; I ended up making a thread (RTL-SDR module/mounting - general thread) dedicated to my attempts. I solved the USB issue by tapping into the pads where the existing USB ports are; I soldered onto that, and crimped my wires onto Dupont pins so I can remove for testing/etc. It’s minimally invasive, and as long as I don’t try to use that port while the SDR is connected I haven’t noticed any issues.

I’d love to see how the HackRF works out, I’m sure it would be even better than my cheapo dongle

Ah moving to the correct thread, tks