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PaxInstruments / t400-electronics

Electronics for the Pax Instruments T400 temperature datalogger
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Micro SD card does not reach enclosure edge #79

Closed charlespax closed 9 years ago

charlespax commented 9 years ago

The SD card should be at the enclosure edge when it is inserted. We will probably need a new connector.

charlespax commented 9 years ago

There is another common connector that hangs over the edge. I believe the connector from Seeed Studio works. The ones I have from the OPL kit I bought match the ones I got from Seg market.

screen shot 2014-12-06 at 01 00 07

charlespax commented 9 years ago

@starno , How far over the edge should the SD card slot hang? When the Sd card is pushed in all the way the SD card edge should match up with the enclosure edge. Maybe take some measurements and upload a picture for Sam.

starno commented 9 years ago

@samchoy88 lets do 2.5mm over the edge

samchoy88 commented 9 years ago

Currently we are using Sparkfun Micro SD connector. https://www.sparkfun.com/products/127 The microSD card only available for 1.6mm (in Lock position), please see below picture.

microsd card

charlespax commented 9 years ago

Sam, please switch to the microSD card connector I mention previously. It is from the Seeedstudio open parts library. It's one of the most popular connectors on the market. I have a bunch of samples I can give you next time you're in SZ.

charlespax commented 9 years ago

The card slot should hang over the PCB a little. I'm not sure by how much. It would be good to have a drawing for this part.

screen shot 2014-12-21 at 14 53 52

When inserted the card should be flush with the enclosure, so the card will then be 3.64 mm over the PCB edge.

screen shot 2014-12-21 at 15 00 57

samchoy88 commented 9 years ago

Updated Micro SD card position As the card lock at 2.2mm away from the edge of connector. If you want the SD card flush with the enclosure, the connector should hang out 1.44mm away from PCB edge. (3.64mm-2.2mm)

image

image

charlespax commented 9 years ago

Cool. We have a 2.14 mm gap between the PCB and enclosure, so hanging over the edge by 1.44 mm should not cause any interference. screen shot 2014-12-22 at 21 57 02

starno commented 9 years ago

Can someone point me to the data sheet or drawing for this connector? I want to get it modeled into the enclosure CAD

starno commented 9 years ago

Is it the sparkfun part linked above, http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Components/General/15882.pdf or a new one?

charlespax commented 9 years ago

That Sparkfun part is the old MicroSD connector. We're now using one that has solder tabs a little further back, which allows it to hang over the PCB edge.

It should be one of these two form the SeeedStudio Open Parts Library. I believe these two parts are interchangeable. http://www.seeedstudio.com/wiki/images/3/3e/3300060P1.PDF http://www.seeedstudio.com/wiki/images/6/62/320090002.pdf

See https://github.com/PaxInstruments/t400-enclosure/issues/53

starno commented 9 years ago

Ok, I'm seeing some discrepancy here from @charlespax 's numbers. This is the distance I see from the outer edge of the pcb to the edge of the enclosure: screen shot 2014-12-27 at 9 16 59 am As modeled with the SD card locked 2.2mm from the connector: screen shot 2014-12-27 at 9 19 23 am The drawing linked above also has some missing information, but I think the important dimensions are highlighted in blue below: screen shot 2014-12-27 at 9 21 52 am The connector is modeled 1.44mm off the bottom edge of the pcb, and shares the same centerline as the old connector (23.51mm from the side of the pcb). @samchoy88 does that match where you have it placed? If not, let me know where to put it.

Unless I'm missing something, I think we need to decrease the 1.44mm a bit

charlespax commented 9 years ago

Looks like it's my fault. In the screenshot from my previous comment I chose the wrong measurement dimensions. I chose the normal distance rather than the dY distance. @starno do you agree or am I missing something again? Should the connector hang over the PCB by 0.79 mm (2.99-2.2)?

screen shot 2014-12-21 at 15 00 57

starno commented 9 years ago

connector hanging over the PCB by 0.79 mm looks correct to me

starno commented 9 years ago

I decided to change the overhang to 0.7mm from the PCB edge. The long side of the connector was cutting it a little too close to the enclosure's inside edge.

0.79mm: screen shot 2015-01-03 at 3 19 54 am

0.7mm: screen shot 2015-01-03 at 3 28 54 am

charlespax commented 9 years ago

Good call. I can see it's a bit close in the SLA print.

samchoy88 commented 9 years ago

I have a little bit confuse on the SD card hang out distance. Current the Card lock position is at 3.64mm away from the side of PCB. image

charlespax commented 9 years ago

@samchoy88 you are correct. The topic of this issue is the clearance between the inside of the enclosure and the Sd card slot. They were a little too close.

charlespax commented 9 years ago

I think this is solved in Electronics version 0.10. Let's revisit it in Electronics version 0.11 (https://github.com/PaxInstruments/t400-electronics/issues/144) if it's a problem. See the footprint verification issue (https://github.com/PaxInstruments/t400-electronics/issues/145). Closing issue.