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culbert-alexander / LED_LIGHT

Project for Duke University BME 590L
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Milestone 04 PCB #8

Open culbert-alexander opened 5 years ago

culbert-alexander commented 5 years ago

Hopefully the PCB is at a good start. Known issues may be the clearance, and whether or not the bottom layer is actually all copper. I plan on using through-hole for everything. MCU code to come later once I figure out ATTiny.

sphaerobolus commented 5 years ago

FYI, our ATTinys are SMT.

The 2-row header you've used for the Tiny is a recipe for a headache. Best to use the correct footprint.

Don't need to parallel traces on top and bottom of board. Put a trace on either side, but not both.

Bypass cap should be close to the Tiny's power pin, between pin and ground. The bypass cap here is in between power supply and the Tiny's power pin. This will block the DC power, no good.

brinnaebent commented 5 years ago

Why do you have a route on top/bottom (the same route?). It looks like you shouldn't need that 2nd layer at all. Connections okay. Consider clearance around header for whatever microcontroller you are plugging into it.

culbert-alexander commented 5 years ago

PCB should be all but fixed at this point. Please note I'm using through-hole ATTiny85s that I bought and plan on soldering a socket in. The footprint chosen was pulled from DigiKey's ATTiny85 library.

sphaerobolus commented 5 years ago

Looks good now. One thing we must have missed before: I don't see a pullup or pulldown resistor on your momentary switch. Do you have an internal?

culbert-alexander commented 5 years ago

Yep planning on using the ATTiny85's internal pullup resistors

culbert-alexander commented 5 years ago

Shorted my PCB soldering. Feeling very foolish now...

mlp6 commented 5 years ago

Uh oh... salvageable?

culbert-alexander commented 5 years ago

Unclear. I believe having the top plate being ground with little traces for everything else has caused me to have significant overlap in my solder between the trace and the large ground plate. Thus, the short. I've attached a picture of my PCB, though I know just looking at it may not help. img_4999

At this point, is my best move to slightly redo my PCB with a ground trace connecting all the grounds, versus the top plate? This would allow my soldering to be this messy and not connect any pins to ground (assuming my assumption here is correct, in that that's the issue).

brinnaebent commented 5 years ago

Hi Alex,

I think your issue is definitely messy soldering. The solder should be a small bubble and shouldn’t overlap with the rest of your board. From the picture, it looks like you are shorted in at least 3 places. I think your best bet is to re-do the board and be very thoughtful when soldering your next board.

On Dec 2, 2018, at 9:59 PM, Alexander Culbert notifications@github.com<mailto:notifications@github.com> wrote:

Unclear. I believe having the top plate being ground with little traces for everything else has caused me to have significant overlap in my solder between the trace and the large ground plate. Thus, the short. I've attached a picture of my PCB, though I know just looking at it may not help. [img_4999]https://urldefense.proofpoint.com/v2/url?u=https-3A__user-2Dimages.githubusercontent.com_43040714_49350481-2D25c7dc00-2Df67d-2D11e8-2D87a7-2D408f5f7aab30.JPG&d=DwMFaQ&c=imBPVzF25OnBgGmVOlcsiEgHoG1i6YHLR0Sj_gZ4adc&r=mPjOjxCawj_Hh-0XYfpdrRihm7CXJ9fK-gYjzfORXI4&m=XxyNPT53Zw9-p-LkrvjiplS471sUfNzL1wc9lcslW0A&s=-8CCG6fbht7c4G7MJb8RsYKCGPT09RCbZ2HY1RktiLg&e=

At this point, is my best move to slightly redo my PCB with a ground trace connecting all the grounds, versus the top plate? This would allow my soldering to be this messy and not connect any pins to ground (assuming my assumption here is correct, in that that's the issue).

— You are receiving this because you commented. Reply to this email directly, view it on GitHubhttps://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_culbert-2Dalexander_LED-5FLIGHT_issues_8-23issuecomment-2D443574314&d=DwMFaQ&c=imBPVzF25OnBgGmVOlcsiEgHoG1i6YHLR0Sj_gZ4adc&r=mPjOjxCawj_Hh-0XYfpdrRihm7CXJ9fK-gYjzfORXI4&m=XxyNPT53Zw9-p-LkrvjiplS471sUfNzL1wc9lcslW0A&s=vle9kAxOMCe0PKyXLoaatYbXK2KPt1AWFXEoTl0vGG0&e=, or mute the threadhttps://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_notifications_unsubscribe-2Dauth_ApiE2olpJ2pj0EhqiZpoVMLQ-5FUinE-5FPDks5u1JNzgaJpZM4YU9DK&d=DwMFaQ&c=imBPVzF25OnBgGmVOlcsiEgHoG1i6YHLR0Sj_gZ4adc&r=mPjOjxCawj_Hh-0XYfpdrRihm7CXJ9fK-gYjzfORXI4&m=XxyNPT53Zw9-p-LkrvjiplS471sUfNzL1wc9lcslW0A&s=ziPqW8u3pZnKxuXWuL0j9xLYlBzb1m4ObI973kb_10w&e=.

culbert-alexander commented 5 years ago

While I don't doubt it's possible to solder that small, I don't think I'm currently capable of it. So I just removed my large ground plate and made it a new trace (cue soldering leeway). Thanks for the advice!