I think you've misunderstood me. I won't need to change the thickness of either ground ring (top or bottom). I'm talking about the trace connecting R1 and Pin 7 which runs underneath the MCU. It's on the top side of the board (far left picture) and has 3 'legs' connecting Pin7, R1, and R2. It's very fat but really doesn't need to be as it's just the voltage divider output for the MCU to read. If I thin out that trace I can move the IC+/R1 trace to underneath the MCU which will allow for clean access and easy grounding of Pin 5 if the user desires it.
There are a few other minor tweaks I want to make but nothing that will change any dimensions or component positions.
EDIT: Funny how looking at things a few days/weeks later reveals things you never saw the first time around. List of changes to be made tonight:
Thin out R1/R2/P7 trace.
Move P8/R1 trace so that P5 has clear path to PCB ground.
Move the 3 vias on left of board to above P1.
Add GND solder bridge points for P2, P3 and P5.
Connect rear GND of AMC chip directly to large ground ring on base of PCB. Also run trace from middle front GND pin to rear GND pin.
Move via on rear GND of AMC chip so that it's not under the pad of any IC
Add a short handled 8 lb sledge to Dale’s list of components.
I was so proud of how neatly I got it all done, and then it won’t work! I need to try to de-populate it without tearing anything up and start over, but I feel better about that now with my smallest tip in working order again.
Would like to get the parts new though, instead of stolen off a board. Then everything would be fresh and easy to solder, but of course the mcu wouldn’t be flashed right? I can get that one, just those tiny pads under the resistors I tend to tear one end off the resistor and can’t solder it back onto the 10.
Your right of course. The only wide trace I was thinking of was the ground ring. Could you go ahead and make it (gnd) a bit smaller to leave more clearance between it and led±? What about just plunking R1 across pins 7 and 8 and eliminating the trace and pads completely? There must be a word for gauche in circuit design.
Dale, I have some unused drivers. Do you want me to pop one in the mail?
I'm literally working on it as we speak. I've already corrected the trace between R1 and IC+. I can't fit the resistor across those pins as there is just not enough space.
Do you need the GND ring to be smaller or are you jsut concerned about the gap between it and the LED+ and LED- via?
Just concerned about the gap. The parts layout is already fine on that side. A common difficulty amongst us smd newbies seems to be solder bridges on close pads/parts. Not an issue when those pads are connected by traces. I don’t think it’s a big issue if the wires go on the board first and you can approach the pads from a different angle but trying to solder the led+ wire after everything else would be difficult. If you were to do a board or two as you suggested would you consider doing a video or pictorial to go along with it. I would be just passing along my own ignorance/bad habits. Even with a great recipe and top notch ingredients people still make flat cakes though.
That looks nice. What do you think?
Edit -given that we’re stacking 7135’s is there any advantage to increasing the area of the ground plane on that side?
Let me know when you send off to have the prototypes made at OSHPark, I will front you for 3 of em, I should have most of the stuff I need soon to try V1.0, really digging the V2.1 though
Fair enough - I keep forgetting that people intend on assembling these use a solder iron. I could do a video but honestly I couldn't do what you do with a solder iron. The best thing I ever bought was a reflow gun and solder paste! It is seriously a game changer. Mine only cost me $60, and that's Australian so you could probably grab one off eBay Stateside for a bit less.
Me? I think it's the greatest thing ever haha. Seriously though I'll sleep on it and look again tomorrow. Issues and improvements are NEVER obvious if you've been staring at things for too long. That and it'll give others a chance to pipe up. I've already moved the 'stars' for pins 2 and 3 up 0.05mm so that they line up with the matching MCU pins. It was annoying me lol.
Getting close now but I’m hoping to get the boards made 1mm thick or even less if possible and Oshpark only does 1.6mm. When the boards do get ordered I should be able to front them easily enough if a batch is done. I would only ask cost plus shipping but it still might prove more cost effective to open source the files so members could have boards done more locally. V1 is yours to play with but it would be fun to see what you do with it.
ill buy few V2 if u dont mind once done, or if the open source is shared it would be nice to buy what i want just encase i screw up :) very nice work guys
Nice. :bigsmile:
Could you move D1 closer to the LED+ via, next to the 7135 instead of in front of it? I plan to place a second 7135 (upside down) where D1 is.
I don’t understand the fuss about traces running under components, like the 7135 chip…Qlite does it on their boards.
The new board looks very nice! Pos and Neg locations separated to opposite sides of the board? Good call! This tiny project has really come along nicely, well done!
Just saw the offer Scott, thank you…I have some on the way and hope to be getting more on the short bus from Richard later today.
Question…can smaller components be used with the same values? Like a smaller resistor and capacitor? The solderable ends pretty much cover the pads, not a big deal in reflow but major with a soldring iron. Tin the 2 pads, lay the component on top and place the iron on one end, it sits down into the liquid solder. Move to the other end and the component can’t swing down due to the other end being nailed down. With a smaller resistor, pads are open to iron placement and the solder joint is easy. Even to my naked eye. While I can simply read the values on the resistors, how do I determine the value of that capacitor? And how critical is it to exactly match the values? Barring success again, how essential is it to make impact in dead center of the rapidly approaching sledgehammer head? What? I wouldn’t! Just wondering…
Helios, I can see how that might be done if C1 were grounded to the outer ring instead of under the IC and input plus were snaked between the 7135 pads but it would locate the D1 pads very close to the ground ring and 7135+. One of the design constraints was locating components with as much space between them as possible and that location would be much more likely to generate a dead short or direct drive. Is stacking not an option for you?
Dale, on the smaller parts I held them down with either a small screwdriver or the blunt end of a bamboo skewer(teriyaki stick?) and soldered both ends at the same time. Bringing the iron tip in from the side allowed this but had a tendency to shift the part and holding it down harder just increases the risk of small part tiddlywinks( that happened but working in a cleared area meant I found it each time. A fine linen tablecloth or pillow case might help to keep it from skipping away. You might ask the wife where those might be found. 0:)
Always wear safety glasses when angry. A few suggestions for recalcitrant board disposal are: a vise, slow but sure; train tracks, hard to identify or even find the remains but a safe bet if you’re squeamish about twisted traces and crushed fiberglass; my personal favorite has always been the waffle head framing hammer, quick, decisive, and shows your mastery as effectively as anything else. Just remember this, frustration is anger directed inwards. Be careful you don’t hurt what you’re really angry at. This is supposed to be a safety vent not a tragic event.
Aw, I’m just funnin! I’d never actually smash up a tiny little driver or anything else. Much easier just to fix it and use it and move on.
My biggest issue wasn’t with the tiny board itself, it was in removal of the parts safely from the original donor board. Never done that kind of stuff before, so it was a big learning curve.
My first attempts at removal from the bigger board had me killing components. So I tried a new method, I used the hot soldering iron tip to push the XActo knife blade under the components making contact with both solder points simultaneously from underneath. This worked well for the components, but tended to strip the pads off the board. This is now my dilemma, how do I remove these from the Tiny10 without damaging it so I can start over?
I’ve seen stacks 8 high though I’ve haven’t needed to do more than 3 myself. I typically use some AS5 adhesive to build the stack and lay them in a line on the ground tab to even them up. With the led-wire already stripped and in place bridging the output pins is a cinch. Some small guage solid wire with enough pretinned to touch each input plus pin is done the same way and trimmed with snips or fingernail clippers. A short piece of copper house wire layed between consecutive pair of ground tabs aids bridging those without affecting the profile on that side. Some people bend the pins, some say you shouldn’t and don’t need to. I’ve done it several ways and they all seem to work. Too much heat can kill these chips. They are fairly tolerant of abuse but not indestructible.
I liked the purple too but we’ll end up with whatever is cheapest.
Lay the iron over so that both ends of the component are heated and slide the part sideways off the board. And use flux again, it helps wet the solder so it actually melts easier and then wait for the solder to melt. Don’t rush it. The knife is likely to damage the solder mask even if you get the parts off intact so a toothpick or Popsicle stick is safer to probe with.
What? I wouldn’t! Just wondering…