4.1 in SMD - It can be done!


 
D

Dave Casazza

TVWBB Fan
Enjoy!

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Tools:
Toaster Oven
Solder Iron
Wick
EZ Profile

Uses:
ATMEGA328P-AU

One flub: I need to get an SMD crystal!

Breaks out probes to RJ45:
6mv8j3eNzM4UyCkwVSZHXMf0TUlnghIaJ3j7fyHFLbA=w276-h207-p-no


***
22.5" One Touch Silver // UDS with HM4 // Mak 2 Star
 
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Ha HA! You're nuts man. What part did you use for your SOT-23 3.3V regulator? I'm actually working on something else that needs one (30mA max). And what is EZ Profile?

One critique, the 0.1u decoupling capacitor for the shift register should be as close to its VCC as possible.
 
This is pretty awesome. It would be cool to see if the footprint could be shrunk but this is beyond my skill.
 
I don't see how you can't try your hand at footprint minimization. ITead will permit you to spend $20 to fab your board for 10 copies, although you have to wait for the boat to come in from HK.
 
Unfortunately the size of the PCB is more dictated by the size of the physical connections than the components on it. The only direction you can shrink it is in width, but you'd have to replace the SD card with a trimmed version for that so it seems like a hassle. You could probably do away with the 28 pin interface connector if you are confident enough to solder it directly to the Pi's pins.

All in all, it can't really be shrunk at all without making some sort of sacrifices.
 
Not yet. circuit building tends to be a winter activity. Too much fun to have in the summer! Also, it depends on the features. I tend to drop the features that really aren't well used.

Frankly, I screw up more PTH than SMD boards when soldering. Not sure why we haven't moved to SMD yet, but maybe if enough people pipe up, we can change the design to SMD.
 
Well, Bryan put the Eagle files out there so it's just a matter of laying out the circuit board for SMD components. That said, I am firmly against the move to SMD for this project because I think it would dwindle down the number of potential builders to next to none. I think just folks with good eyes, steady hands and electronic experience would take on the project if it were all SMD. And what is to gain from going all SMD really? The rPi and the display aren't going to get any smaller, so you wouldn't be shrinking the overall footprint of the HM by very much, and there becomes a point where smaller isn't better. The through hole V4,2 of the HM has a pretty small footprint as it is, if it gets too small it might get pulled around by all the cables connected to it.. At any rate, hat's off to anyone that wants to take it in the all SMD direction themselves, but I don't think it is for everyone...
 
I personally have no problem doing SMD work, I've done 5 or so thermocouple amp circuits now with no problem. It's others that are less experienced than you and I that I think would be shied away from the project if it were all SMD. No matter what method you use to melt the solder you still need to be able to see the parts clearly and be steady enough to place them exactly where they belong... Since there is no huge advantage to miniaturizing the HM board I see no reason to complicate things... that and I don't have a toaster oven! LOL
 
I can appreciate both the pro and anti SMD arguments, but I think in the end, SMD is going to win out. It's really quite easy to hand solder the larger package sizes, as Dave pointed out, and swapping/replacing components is also easier with SMD. The multi-direction button that the HeaterMeter currently uses is only going to be available in an SMD format sometime in the future, since the through hole version is being discontinued. I don't think the switch to SMD will dwindle down the number of folks looking to build a HeaterMeter by much. From what I've seen, quite a few people have wet their feet into the world of soldering and electronics with the HM project, and I think most of them will be able to figure how deal with the change to SMD. There are also a lot of great video tutorials on SMD soldering techniques that can help those getting into it.
 
OK, we will have to agree to disagree, but I hope Bryan never decides to go all SMD with the DIY Heater Meter boards... The majority of people without experience in electronics are intimidated enough by the thought of building up the through hole board, let alone all SMD...
 
There's no reason we can't have the best of both worlds. Bryan keeps doing a through hole design and with each "prime time" release, others can adapt it to SMD. This type of thing happens in the software world all the time.
 
Yah, that's why I pointed out that Bryan has made the EAGLE schematics available so anybody that wants to make a SMD version is free to do so, I just don't think it would a good move to make it SMD or the highway.....
 
Im with Ralph, and I believe the HM as a hobbyist project for the person who has no knowledge of soldering, would never be what we have today if it were only SMD version. In the BBQ world, there is no advantage to have a SMD version. Granted, after learning how to SMD with the release of the HM4.2.4 board, its pretty easy and if a SMD version of the 4.2 was available, I would give it a try.
 
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I think the argument for SMD is cost, either for the DIY or commercial aspect (if Bryan chooses to sell some, which I think he could). The learning curve is steeper, but it's not THAT steep. An hour on youtube & an hour of practice and you can SMT solder. If you've never done through-hole, I think it should be suggested to learn both - with encouragement from the forum. I significantly cut the cost of my PCBs & components for another project by using 0603 resistors & LEDs (16channel relay boards). You can fit 2-3 0603 components in the same space as a single through-hole resistor.

I'm kicking around a 4.2-clone in SMD & on the beaglebone platform just to see if I can do it. I'm not great at electronics or software, so the HM project will be a road map & I'll try to solve the specific challenges on the BBB (which I'm slightly more familiar with than RPi). I want to miniaturize, customize, learn a few things & add my own touches to it. It won't be done soon, but it will get done. There's a few notes on paper right now & I have the schematics marked up w/what I want to use & what won't work w/BBB.

The HM project caused me to learn to create a PCB for my fireworks controller project, I would have never done that w/o Bryan's EXCELLENT documentation, support & well-done project (perhaps juicy medium rare is a better compliment for the HM?). This forum + github + the professional manner in which he goes about things are a how-to for DIY electronic projects, IMO.
 
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