BiDi micro-USB guard
A guard for the SDI end of the original micro-USB BiDirectional Micro Converter, so a tug on the lead doesn't lever the port.
What it does
The first BiDirectional Micro Converter took its power through a micro-USB socket on the SDI end, beside the two BNCs. Micro-USB was never built to be a handle, and it takes rather less levering than USB-C before it gives up.
This is the BiDi USB guard redrawn for that model: the same plate over the SDI end, clamped on by the two BNC nuts, with the tower round the plug made smaller to suit a micro-USB moulding. Once it's on, the plug can't back out or be levered about, and windows over the SDI lock and power LEDs mean you can still see whether it's happy.
Where it stands
v0.1. I've modelled it and checked it in software, but I haven't yet printed one and fitted it to a real converter. The steps below are written from the model, and the socket and LED positions come from a listing photo, so they're good to about half a millimetre. Once one has been on a real one, I'll update this page with anything that turned out differently.
Print your own
Fitting it
You'll need
- Your fingers, and a spanner or nut driver to give the BNC nuts a nip
- The micro-USB lead you'll be using with it
Check your micro-USB plug first. The pocket is sized for the flat moulding with a "B" on it that Blackmagic's and Decimator's stock leads use, measured from photos. A bigger moulding won't go in, and a much shorter one can back out a little before the guard stops it.
- Plug the micro-USB 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 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 in the slot in the tower's side.
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. On the power LED's side the wall has a slot in it for the light, and still stands above and below the slot.
The LEDs
On this model both LEDs sit about 4 mm below the middle of the panel, a good bit higher than on the 3G. The SDI lock LED, between the BNCs, shows through a countersunk window. The power LED is right beside the plug's moulding, so a slot runs from round it out through the side of the tower.
Both positions, and the socket's, came from a hand-held listing photo, not a converter on the bench. If a window's off, that's the measurement that was wrong, and I'd like to hear about it.
Will your leads fit?
| Micro-USB plug moulding | Up to 10.6 × 6.8 mm across |
|---|---|
| Moulding length | 13.2 mm from the panel to where the boot starts |
| Sized for | The flat "B" moulding on Blackmagic's and Decimator's stock micro-USB leads |
Micro-USB mouldings vary a lot more than USB-C ones. A bigger or longer one needs the guard re-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
In software only, against the model. Nothing here has been tried on a real part yet, which is what the second list is for.
in software Both BNC nuts turn freely over the plate, with 0.3 mm to spare at their corners, and seat on it.
in software Nothing comes within 0.3 mm of either LED, all the way up the tower.
in software A 10.6 × 6.8 mm plug body goes in, the cap sits over both ends of it, and it's walled in on every side.
not yet Where the micro-USB socket and the two LEDs really are, to better than half a millimetre.
not yet Whether your micro-USB lead's moulding fits the pocket.
Where the numbers came from
The plate and BNC holes are the BiDi USB guard's, which has been test-fitted on the 3G model, and a straight-on listing photo of the original shows its BNCs in the same place. The socket and LEDs were measured off that photo, scaled by the micro-USB socket's bezel, whose size came from Blackmagic's to-scale render of the one-way models.
More views
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.