BiDi USB guard
A guard for the SDI end of a BiDirectional Micro Converter, so a tug on the USB-C lead doesn't lever the port.
What it does
The BiDirectional Micro Converter takes its power through a USB-C socket on the SDI end, squeezed in beside the two BNCs. It's a perfectly good socket for power and a poor handle, and a handle is what it becomes when a snagged lead swings the converter about by it.
This guard is a plate over the SDI end, clamped on by the two BNC nuts, with a tower round the USB-C plug. Once it's on, the plug can't back out and can't be levered sideways, so a tug on the lead goes into the plate and the nuts rather than the socket. Windows over the SDI lock and power LEDs mean you can still see whether it's happy.
Where it stands
v0.1, test-fitted on a real converter. The steps below were written from the model before that fit. If anything in them doesn't match what you find, tell me and I'll fix the page.
Print your own
Fitting it
You'll need
- Your fingers, and a spanner or nut driver to give the BNC nuts a nip
- The USB-C lead you'll be using with it
- Plug the USB-C lead into the converter.
- Take the nuts off both SDI BNCs. Keep them handy: they go back on over the guard.
- The tower has one open side. Feed the USB-C cable in through it and into the slot in the tower's top.
- Push the guard onto the end of the converter, over the two BNCs, so the plug goes up inside the tower and the plate sits flat on the panel.
- Put the nuts back on. They seat on the plate. Finger tight plus a nip is plenty.
- Power the converter up and check both LEDs: the SDI lock LED through the window between the BNCs, and the power LED at the foot of the light well in the tower's corner.
How it holds
The tower's top sits on the plug's moulded body, so the plug can't back out. Walls hold it on three sides and two hooks across the open side hold the fourth, so it can't be levered either.
The LEDs
Both LEDs on this end are near the bottom edge of the panel. The SDI lock LED, between the BNCs, shows through a 3.6 mm window that's countersunk on the outside, so you can see it from an angle.
The power LED is the awkward one. It sits right beside the plug's moulded body, under where the tower's corner would be, so a hole in the plate would show nothing. Instead a light well runs down the whole height of the tower's corner, with the window at its foot.
Both positions came from Blackmagic's render of the converter, not from a converter on the bench. If either window is off, that's the measurement that was wrong, and I'd like to hear about it.
Will your leads fit?
| USB-C plug moulding | Up to 13.5 × 7.5 mm across |
|---|---|
| Moulding length | No more than 18.2 mm from the panel to where the cable leaves it |
| Sized for | Blackmagic's own USB-C supply |
Moulded plugs vary a lot. A longer or fatter one won't go in, and needs a guard made to suit it.
Taking it off
- Take the nuts off both BNCs.
- Slide the guard off the BNCs, and the cable out through the tower's open side.
- Put the nuts back on the BNCs.
What's been checked
The first item is from the test fit. The rest were checked in software, against the model, before it.
test fit Test-fitted on a real Micro Converter BiDirectional SDI/HDMI 3G.
in software Both BNC nuts turn freely over the plate, with 0.3 mm to spare at their corners, and seat on the full 2 mm plate.
in software Nothing comes within 0.3 mm of either LED, all the way up the tower.
in software The plug pocket is nowhere tighter than in the part the converter's numbers were measured from (see below).
not yet Whether both LEDs show through their windows on a powered converter.
not yet Whether USB-C plugs other than Blackmagic's own fit.
Where the numbers came from
The fit to the converter (the BNC holes, the plug pocket, its roof and the hooks) was measured from dj12bas's BiDi USB Protector on MakerWorld, and the LED positions from Blackmagic's end-view render, scaled by the catalogue size. Everything else is my own design, written from scratch, and the test fit is what proved the numbers on a real converter.
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Fitted one?
Tell me how it went
If you've put one on a real converter, I'd like to hear about it, good or bad: whether it seated, whether your plug went in, and anything that got in the way.