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Hmmm. Does this PicoBlade connector (J2) look too close to the PMOD to its left?
It only needs to get connected once during assembly, this won't be frequently actuated, so it's OK if it's a bit annoying as long as I don't like physically collide.
(The PMOD is just-in-case GPIO expansion and I have no plans to use it as of now)
@azonenberg I believe the standard requires modules to optimally be 0.800" wide. Depending on how wide the outside of the connector for the PicoBlade is, I think it should just fit.
@petrillic I'm not sure how the width of the module is an issue.
The PicoBlade is the gray connector to the east of the PMOD. The cable will come in from the west, draped over the PMOD, then curve down towards the PCB and plug into the west side of the PicoBlade.
The question is if I've left enough space between the board-side connector and the pins of the PMOD to reasonably allow mating and unmating.
@petrillic (I suppose the *height* of the PMOD in the vertical axis could be a consideration, but by the time you get past the mated connector pair the PicoBlade wire harness can easily be routed anywhere to avoid it)
@azonenberg oops, my mistake, didn't even think about which connector was which for some reason. Sorry about that.
@azonenberg without measurements, my only concern would be the bend radius on wires coming out of the connector before its inserted into the PicoBlade.
@petrillic Yep.
The wires are <1mm OD so I think I'm OK (the face of the PicoBlade is almost 9mm from the PMOD pins) but I'm trying to see if I can squeeze a little more distance out to be safe.
@azonenberg@ioc.exchange I'd maybe try to place it diagonally? The current orientation seems ok-ish, but I feel like I would be very annoyed trying to plug it in
@azonenberg Rule of thumb: if you have less than the width of your index finger or the thickness of your thumb space between the plugs, then it's too little space. I usually go for something in the order of 2-2.5cm as the minimum, 3cm if I can. Makes life a lot easier. But of course, it's also a matter of available space. If you have 10 connectors, you can't space them 3cm apart.
@attilakinali Yeah and this is also a mate-once connector. Barring some kind of major problem I won't ever be taking this apart.
So if I have to use tweezers or something to nudge it into place that's not a big deal at all.
If it's physically impossible to mate without, say, desoldering one half of the connector? Different story.
@azonenberg Hmm... in this case, I think it's ok...ish? I would only check the wire bend radius. Specifically that the wires don't press too hard on the PMOD. Other than that, it looks ok for insertion/removal using tools.
@azonenberg check out this small, SMD, air mover I saw at CES, no moving parts. They were picky about photos but about 20x20mm x 1.5mm tall, 1 watt I think
@0h00000000 Did they say how it worked? Fully solid state air moving with no moving parts is... rare.
I know of one company that was exploring this via thermal transpiration (Knudsen pump). Did a bunch of MD simulations for them but it was basically in the realm of space elevators, "would be great, if only we had a magic material with properties that are theoretically possible but far in excess of anything we know how to produce"
@0h00000000 Looking at their website... "no moving parts" is a bit of a stretch, it has ultrasonically vibrating elements inside it that I'm guessing are probably piezos or something.
Interesting tech but definitely not the same (OTOH, thermal transpiration normally requires active heating so i'm not sure it would be useful as a cooling fan anyway since you'd be blowing *hot* air...)
@azonenberg Depends on how you channel inflow/outflow, you could suck in outside air with correct channeling.
If I recall correctly, is was an electric field effect, and could do surprisingly high pressures for it's size. Unit cost was high for mass production, but probably perfect for projects. Their target market was laptops.
@azonenberg It could have been piezo, but I don't remember super clear, it was CES, I was in a rush, and it was 6 months ago, but I do remember that I was suitably impressed.
@azonenberg@ioc.exchange @0h00000000@ioc.exchange The biggest issue for it is that AFAIU dust protection for it is mandatory because it's very sensitive to it. At least it has very high static pressure to blow through whatever filters you need to put in, but it's a fair bit of annoyance.
@0h00000000 Lol.
Basically you need a membrane a micron or so thick, with few-hundred-nm wide pores punched through it.
It needs to be heated on one side to a decent bit above ambient, while the other side is held at ambient or ideally chilled.
It needs to be thermally nonconductive enough that you don't burn an absurd amount of energy maintaining the thermal gradient.
And it needs to be stretched across the aperture of your pump/engine/fan/whatever on some kind of support grid that will let it maintain the required static pressure without rupturing.
@azonenberg vertical connector instead? I’m always a bit wary of horizontal connectors being placed so far from the edge of the board for exactly the reasons you’re worried about. If you rotated it 90° clockwise that would help with clearance too.
What’s J2 for anyway? That might guide the decision too.
@jpm It's the sideband control (3.3V standby, remote on/off, I2C sensor access) for the main 12V supply feeding in the Mini-Fit connector.
I intend to hook it up once and not touch it again, and the PMOD is not intended to be used (it's mostly there as extra GPIOs for me to trigger a scope off or something during firmware debug).
@azonenberg ah, associated with that Molex power connector just to the north? Personally I’d rotate J2 90° clockwise, so the power and comms cable assemblies can be tied together, with the comms being longer and doing a single 90° bend in instead of a pair of 45° bends in an S
@jpm The idea was that the comms cable harness was going to be draped over the top of the pmod and just gently curve slightly up then parallel the power cable.