#141  
Old 28-07-2016, 10:36 AM
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wasyoungonce (Brendan)
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Hi Luka...I'm alive....!


any mistakes..it was the drugs Anyway I'll go thru each you listed to clarify:

  • Schematic shows mega328P.
I used this device package (element14 eagle libraries) as it's the only one I could get for TQFP32 for this device. I believe the pin out is the same as ATmega328. Thus it shows as 328P in my BOM. I've amended the schematic name to ATmega328.

This raises an issue with CAD drawings...who does the drawings for different PCB CADs? In this case Element14 has an agreement with many suppliers.

  • DD6 - your footprint is SO14 while Grim's BOM shows SOIC14
I looked at datasheets prior to putting it down, yes it says S014 but drawing showed part number is "D" variant which is a SOIC14. Just to be sure, I just measured IC on PCB (using measure tools) and it was 9.6mm x 3.9mm body dimensions, so, it has to be a SOIC.

  • DD9 has part number and value reversed
Not sure on this I removed part numbers from PCB as it was too crowded. I cannot see part number on board for DD9?

  • DD10 and DD11 are both 78L06 in Grim's BOM. However, your BOM shows 78L06 and 7806A.
Yep that;s a typo. I chose a SOT 89 voltage reg and mis typed it when putting down the 2nd one. Fixed now.

  • ZQ1 crystal, your Farnell part number is for 3.68MHz crystal, not 12MHz
Yep this is definitely wrong. I selected 49S standard small thru hole package from variants in parts but this listed it as a surface mount crystal in BOM. No idea how that happened, but it's only in BOM not on PCB or schematic. Just amend manually in BOM.

  • DR3 - Grim has RLB0712-101KL which I found at RS part number 811-8796. Your BOM shows WE-TI-7447462010_5075, Element14 part number 1848262. Both are inductors and more-or-less the same. Any reason you changed this or am I missing something?
Ahhh you have me... I cheated as I couldn't get the correct package and I was too lazy to make my own so I found one close enough but forgot to amend any reference to the wurth package. Yes it shouyld be as on grims list, RLB0712-101K/
  • DR4-DR6 show resistor in the description but they are inductors
Ahh caught me cheating again. Couldn't find 0805 inductor package (in std Eagle library) so I used a 0805 resistor. It's confusing but suffice to say the PCB is ok but BOM is in mucked up. I'll fix this.
  • C11 = 1uf (Grim) or 0.1uF (you)
Yep my error, I've fixed it now.


  • Missing are C22 + C25, C26 + C32 and C37 (aluminium capacitors). I was not sure of dimensions, they do not seem to be mentioned anywhere.


No idea how these escaped..here they are:
C22 , 100uF, 25V, CPOL-EUE2.5-6 , size: E2,5-6 , POLARIZED CAPACITOR, European symbol

C25, 100uF, 25V, CPOL-EUE2.5-6, size: E2,5-6, POLARIZED CAPACITOR, European symbol

C26, 220uF 10V, CPOL-EUE2.5-6, size: E2,5-6, POLARIZED CAPACITOR, European symbol

C32, 220uF, 25V, CPOL-EUE2.5-6, size: E2,5-6, POLARIZED CAPACITOR, European symbol

C37, 220uF, 10v, CPOL-EUE2.5-6, size: E2,5-6, POLARIZED CAPACITOR, European symbol

As you said, we are now starting to get closer and the more eyes that look at this then mistakes will be seen and fixed, thus confidence is high

As for the SIL packages...I've never ordered from ALiExpress or Taobao...found any thing I needed wither RS/Element14/Digikey/Mouser or dare I say Fleabay. Guess I've lived a sheltered life! if your brave enough...then go for it. If you need funds for parts purchases, pls let me know. As for element14...yes I've seen them put up prices. I suspect it from "search demands" . I've always been sus about this. In fact I was ordering "H" bridge drivers for Losmandy Gemini awhile back and the price went up double o'night. I needed them RS had none so I complained as I said the part was xx to fix for the user now it's ZZ. They dropped the price back and gave me discount. Worked for me!

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  #142  
Old 28-07-2016, 01:12 PM
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wasyoungonce (Brendan)
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Oh meant to ask...do you prefer thermals on vias and pads? I think I should do them its easy to do, otherwise soldering to ground plans is a "inert expletive here"!

Also I have the sensor package pads/pins as 1.27mm dia with a drill of .6mm I looked at the SIL package measurements and it lists the SIL pins at .51 nom but I just saw that it can be up to .64. I might need to increase my hole size. Also my pads appear quite a bit larger than the Ukrainian forum images. I like bigger pads and it doesn't interfere...I hope.

I'll fix the drill to .7mm for the sensor....

edit:
Done sensor pin drill holes .7mm. Images loaded to show differences
Also got my 63/37 solder...very very nice. Doing a practice board, the joints are just so clean and shiny. Perfect filleting and much better amount with .56mm solder (could have gone smaller? I feel I've been far to lazy using 60/40 for too long.
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Last edited by wasyoungonce; 28-07-2016 at 02:27 PM.
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  #143  
Old 28-07-2016, 04:46 PM
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wasyoungonce (Brendan)
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Luka just going thru your parts BOM...noticed on DD10/11 you put in RS stock 661-4591, a 6.2V LDO. The LDO is supposed to be 6V version, but ok 6.2V Vs 6V isn't much should be ok though. Just sayin!

Ok found another...VT3, IRLML6302TRPBF, is an extended range min order qty 50 @$.28 ea (50 x $.28 = $14). Alternate at RS is: IRLML6302PBF, 610-6851, in Pk of 5 for $3.93 (@$.786 ea)...exactly same as other one as "TR" reference is just "tape Reel". So the alternate is cheaper.

Also its good to cross check everything! I'll do the whole BOM and check it against the parts on Schematic. I'll go thru all then do a summation post as posting everytime I find something is in dribs and drabs.

Last edited by wasyoungonce; 28-07-2016 at 05:33 PM.
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  #144  
Old 28-07-2016, 07:28 PM
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Brendan, it is great to have you back!!!

Thank you for cross-checking the BOM. I did heaps more work on it last night before ordering lots of stuff (already got the VT3 that you mentioned).

Luckily I did not order DD10,DD11 yet. I totally did not see that the part I picked was 6.2V. Neither was I expecting 6.2V for a part labelled 78L06 when all other 78L06s are 6V exactly.
The alternatives do not look good at RS, they have only 25 packs which are quite more expensive Must do a bit more searching.

I will finish the BOM later tonight, only 5 components are missing now.
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  #145  
Old 28-07-2016, 08:34 PM
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Hi Luka...
I'm up to resistor now but are hurtin a bit so I'll stop for the night, but I have to give you what I found:

Caps C17/C30/C33/C38 are 100uF, 1206 package 6.3V....buuuut...they are on 6V rails...so the original part told to us is wrong, they should be 10V versions. RS, 788-3057, on backorder atm till 15/08/2016. You might find an alternate but they should be 10V versions as these are not as cheap.

C32 should be 220uf, 25V. Some how this was entered as 10V, Its on 12V rail in so has to be at least 16V or above. I found RS 749-7177, 6.3mm x 11mm, 2.5mm pitch (my PCB is set to 2.5mm pitch for electro radials, but if you find one at 2mm or 3.5mm pitch I can change PCB), 105, 7000h life, high ripple , low leakage.

Sorry don't know how these slipped thru!

This appears all atm, I'll email you what I have atm. I haven't been looking at E14 or digikey yet. If there are high count package buys we can break them up and sell to each other.

Brendan
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  #146  
Old 29-07-2016, 12:10 AM
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Hi Brendan

"the resistors are hurtin"... describes it quite accurately
I actually did them all last night so the latest BOM will have them all... hopefully correctly. Email is sent.

Also Faddy commented about condensation problems but he said that his camera seal was working OK. Apparently the housing warmed up (from Peltier) and silica gel does not work above 35 degrees C, it actually releases moisture.

Also Grim said there was a typo in BOM and that R5 is 1K and not 10K. Already corrected in my BOM.

Luka
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  #147  
Old 29-07-2016, 12:15 AM
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wasyoungonce (Brendan)
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Thanks,,,on to it, Yes saw that about heating case. Their HSF is probably too small.
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  #148  
Old 29-07-2016, 12:56 AM
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Looking at AliExpress part here (you may need to clear all aliexpress cookies if you looked at the Russian translation before).

4 x 40 sockets... how many would we need? 40x should do one camera, i.e. one pack should do 4 cameras (if we don't stack pins). Should I get one pack first? It is over a month for the delivery.

It does not specify if it is beryllium copper.
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  #149  
Old 29-07-2016, 11:23 AM
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Just saw some of these on fleabay, here here.

edit:
Sorry they are straight thru pin to pin not sockets. Here is a 1.778mm pitch socket. A little big but can be cut down.
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  #150  
Old 29-07-2016, 12:40 PM
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Ordered one set of sockets from AliExpress. It should be enough for our first round of cameras. It is free shipping anyway.

edit: Just saw your edit with the ebay link. Already ordered from AliExpress.
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  #151  
Old 29-07-2016, 04:17 PM
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Noticed an error on grims PCB layout. He has C26, 220uf 25V electro (on -8V line) with polarity +ve to gnd (0V) on schematic but on etched PCB its reversed (and image). +ve is on R19 side which is the -8V rail. It's wrong, the +ve has to be towards 0V.

I have to flip it around. I suspect they noticed this and just turned it around when building the PCB.

edit:
Done.

Ok Capacitors, C17, C30.C33,C38 are 1206 sized 100uf ceramic (a lot in a small package). RS has them on back order, but we can change size to 1210 RS has some in stk now, 766-1179, $5.95 for pk of 5. But if we changed I'd need to amend the schematic and drawings. Not difficult to do though. I've left it as is atm.

Last edited by wasyoungonce; 29-07-2016 at 04:47 PM.
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  #152  
Old 30-07-2016, 12:42 AM
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Found some 1206s at E14 here. Would they be OK?

edit: SIL sockets I ordered from AliExpress have been shipped.
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  #153  
Old 30-07-2016, 09:51 AM
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yes there fine...I'll leave those caps as 1206 size.
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  #154  
Old 30-07-2016, 06:49 PM
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Hi guys, thanks for warm welcome, and sorry for not responding earlier.

About sockets, I bought these: http://www.ebay.com/itm/111186383448
Now I have stock for the rest of my life These must be cut to needed length, and quality is excellent.

Unfortunately, I have not finished my camera yet. Too much work and family related obligations...

OTOH, my camera PCB is obsolete, version cam84 R3.1. I must design new cam86 round PCB. Brendan, may I ask you for Eagle .sch file?
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  #155  
Old 30-07-2016, 07:34 PM
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Thanks for the link Filip. Just PM me your email address I'll bang of the files to you...it's in eagle 7.5ver. Of course it'll be for a rectangular PCB....but at least it will cut down on some work you need to do. As you know the most difficult part is placement and routing.
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  #156  
Old 01-08-2016, 05:16 PM
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Just testing outputting Gerber files using cam processor. Odd thing, drill file cannot be read (there are no drill plots) with Gerbv unless I use Excillion24 cam processing.

I think its an issue with eagle. all PCB mfgrs use gerber files I can usually upload them at a place like OSHpark to check them. On the subject of PCB mfgrs...PCBshopper looks to be the place to get quotes. Of course depends on the mfgr on the quality of the made board, but, PCB way gives you quotes for all the big suppliers. I did a quick quote and prices range from (for 5 PCBs):
Elecrow: $13 + $40 (AUD) P&P EMS delivered in 13 days, at least I read it as that.
Seeed: $24+$51 (P&P) 12 days; and
It goes up exponentially.

I read the inputs as the PCB costs and P&P. 10PCBs wouldn't appreciably cost a lot more. You can select slower (cheaper) lead time. We also have to have screen printing on both sides and milling the sensor hole.

While I'm confident the PCB is ready....I need to re-check the locating holes and sensor is perfectly centred. They have to be spot on. Also I think I should delete the top/bottom PCB tabs to allow room for connector/dessicant.

Attached is a rectangular PCB showing this and an image of the Gerbv of the PCB.
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  #157  
Old 01-08-2016, 10:33 PM
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Excellent work.

I think we should get 10 PCBs, the extra cost is almost nothing. Also consider that our version 2 (round design) may not work well enough, for example due to the increased noise. In that case I would like to build a 2nd camera on this PCB. A spare would be good as well...

Last chance if anyone else wants to join in.


Also add few $ to those quotes. From my experience they will try to squeeze every cent out of you and we will probably encounter things like credit card fees etc.

By the way, my $12 broken D70 arrived today. No way to test the sensor as the camera is broken, but (in theory) I have two sensors now. Did you get DMSO yet and/or tried "freeing" your sensors?
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  #158  
Old 02-08-2016, 12:52 AM
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I did a bit more research on silica gel and it is not true that it is releasing humidity when heated above 35C, as stated on the Ukrainian forums.

It only desorbs moisture when heated above 104C, see for example here or here.

However, when heated above 25C it will adsorb less moisture. There is a graph here showing the adsorption capacity vs temperature. The capacity drops from about 22% at 25C to about 18% at 50C.

So, heat in the case is not really a problem unless our case gets to 100C
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  #159  
Old 02-08-2016, 01:04 AM
flolic (Filip)
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Quote:
Originally Posted by wasyoungonce View Post
Thanks for the link Filip. Just PM me your email address I'll bang of the files to you...it's in eagle 7.5ver. Of course it'll be for a rectangular PCB....but at least it will cut down on some work you need to do. As you know the most difficult part is placement and routing.
PM sent
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Old 02-08-2016, 01:22 AM
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Quote:
Originally Posted by wasyoungonce View Post
While I'm confident the PCB is ready....I need to re-check the locating holes and sensor is perfectly centred. They have to be spot on. Also I think I should delete the top/bottom PCB tabs to allow room for connector/dessicant.
I am worried about signal integrity (placement of decoupling caps and ground fills and vias).
It's hard to see from your images, I'll wait until you send me project files...

Small changes here can make big difference regarding noise and interference.
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