PCB Experts: OKR-T/6 Custom PCB - Recomendations/Critique

[Rader2146]

I am taking a stab at DIY PCB creation and would like some input on design.

Board size is 1120mil x 500mil (~1 1/8" x 1/2")
Power traces are 50mil minimum. Signal traces, 30mil.
Top layer is only positive voltage. Bottom layer is only ground plane.
Ignore the double row of holes on the OKR pads. I overlaped 2 pads to increase surface area. gEDA will only let you natively create square or round pads.

Top view:

Bottom view:

Top Copper:

Bottom Copper:

 

[Java_Az]

I am taking a stab at DIY PCB creation and would like some input on design.

Board size is 1120mil x 500mil (~1 1/8" x 1/2")
Power traces are 50mil minimum. Signal traces, 30mil.
Top layer is only positive voltage. Bottom layer is only ground plane.
Ignore the double row of holes on the OKR pads. I overlaped 2 pads to increase surface area. gEDA will only let you natively create square or round pads.

Looks pretty good, You could make it smaller width wise by using SMD resistors but if you got the room no big deal.

I have a couple of footprints i made up for that module if you want them one is rounded and the other is square. Would fix your double holes, plus it makes soldering these jokers a lot easier. Footprints are attached

View attachment footprints.zip

 

[Rader2146]

Thanks Java. I probably spent over an hour creating the footprint with the doubled pads because that's was the suggestion I read on the gEDA wiki. As soon a I saw your footprints the light bulb turned on: use the line tool and convert to element. Double

Yesterday I learned how to connect pads to polygons to increase surface area and heat sinking, so Rev1.04 is already in the works. Considering that I've only been using gEDA for a week, the leaning curve isn't too awful.

Big thanks for the footprints. I was wondering how I would ever get it to be single row if I ever wanted to send it out for production.

 

[Java_Az]

Your Welcome ,
yeah it was quite awhile before i learned how to do the footprints, But i etch my own boards so i just used to take the line a bit longer to get the extra pad space. Wasn't till i started doing my own solder masking i needed the pads to be correct so the transparency i use for UV curing was right.

I usually do a silk screen on the footprints these days that match the part size so i don't run into troubles. Not sure how much clearance you have for the OKR to the right edge of the board looks like you might be cutting it close . It is .150 to the center of the pins or 3.8 mm for either side of the OKR module. I went ahead and revised the footprints with a silk screen to match the part size

View attachment footprintsr2.zip

 

[Rader2146]

I plan on using dry film soldermask, just need to find a good UV source. I saw this used in a DIY video:

New 36W UV Gel Acrylic Curing Nail Polish Timer Dryer Lamp Light Spa Kit 20 | eBay

Flatbed exposure units are little out of my price range. I entertained the idea of modding an old flatbed scanner unit I saw the nail polish dryer.

Clearance around the pins shouldn't be a problem. I'm moving the text on the left to the back side where there is free real estate, so that will free up some length to shift a few things if needed. The goal is to fit this into a 3xAA battery box slot. I have to bend the pins to fold the module over the board. I tried this with a strip board but couldn't get the module to lay down close enough with the resistors having to cross over to the ground strip.

 

[Java_Az]

Yeah i went cheap on my UV lights got a 100 off ebay for about 7 bucks and etched a board for them. Run it off a 3 amp variable voltage regulator i had laying around. Works pretty good. 100 x 3mm Bright UV Purple 5000 mcd LED Bulb Light | eBay

 

[Iusedtoanalog]

Hi Raider. Looks nice, are you planning on orienting the okr vertical on this board, or have it dangling off the end like I have seen done with other boards? I have this inherant need to have everything fastened to one single piece when I build something. I have hand built ten off these mods and the only ones that had issues with durability where the ones that the okr was not fastened to the board.

S1 (pin 1 inhibit switch) On all of my mods I have been using a n/c switch to ground for triggering the output on(ground= module off/open=module on). And this allows me to use a 250Ω resistor to the positive atty feed and common with ground to light the led(also allowing a dim-at low-voltage bright-at-high voltage) I have never tried to swich the module on with positive voltage so therfore I would not have a working knowledge of how this specific configuration works.

They do look like something us modders need to make life less tedious, good job. Keep us posted as they become available.

 

[Rader2146]

I'm going to have to bend the pins on the module and "fold" it over the board to get the vertical clearance that I need (14mm max), but the module will be soldered directly to the board.

I have 2 mods that I have built using a NO switch and a pulldown resistor (same schematic this board was built from), but the data sheet reads:

ON = +1.5 V. to +Vin max. or open pin
OFF = –0.3 to +0.4 V. max. or ground pin

So it leaves a few options for us to decide which way we want to skin the cat. I've just never been a big fan of NC switches (for no perticular reason), although it would save board space without the pulldown resistor. Definitely something to ponder.

My main reason for wanting to build this board is that I loathe soldering all the components to the pins with the tiny .067" spacing. I have 4 more modules patiently waiting in my parts box but I haven't build them yet because it is a real PITA to solder multiple leads to a single pin.