Kit vs premade; worth having both?
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Kit vs premade; worth having both?

by vputz on Sun Jan 20, 2013 4:51 am

I've got a design together and have sent off for prototype boards for my testers. But a small number of people have shown a little interest in the device (a redesign of an interface to an old serial device) that don't have any soldering experience and I've considered doing a premade SMD version.

This would let me gain some experience with SMD/stenciling, would reduce PCB size and a bit of component cost; it would also take up a bit more time and I'm not sure it would be worth it aside from the learning experience (which is much of the appeal for me anyway; this is still in the "hobby which helps pay for itself" stage more than anything else).

Has anyone here done something both as a kit and as a premade and noticed one doing significantly better than the other? What price difference makes sense? And are there any sneaky considerations (for example, if this doesn't violate the "no legal advice", is there something obvious like "kits aren't subject to FCC validation but premade boards are"?)
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Re: Kit vs premade; worth having both?

by janekm on Sun Jan 20, 2013 11:26 am

Finished boards can fall into something of a gray area; notably, recently the Raspberry Pi team decided that they had to pursue certification since it become obvious that a lot of their end users were perceiving it as a finished product (after all, a lot of the press around it called it a "£25 computer") as opposed to a component intended to be integrated into a product assembly by others.

In contrast, afaik, the Arduino only pursued FCC certification when they came out with the Uno.

Personally, I would say that if your board is useful enough to someone who would be put off by soldering it together as a kit, go for the pre-assembled version.
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Re: Kit vs premade; worth having both?

by vputz on Mon Jan 21, 2013 4:21 am

That's probably where I'm headed eventually, but scaling up to SMT production even on a home scale does involve some investment (stencils, some sort of reflow device even if it's a toaster oven, and probably a manual "pick and place" linear slide table with a USB microscope; I've done manual SMT before (and stencil SMT placing components with tweezers) at a Sparkfun class, and while it's doable for single projects it's far too fatiguing for production).

It's not clear to me how much more to charge for a finished SMT product above the kit, either. Hmm.

The kit vs finished product question is interesting. For example, I'm doing a V-USB based HID device, but using the stock V-USB VID/PID since it's a low-volume kit, but that would probably not be OK for large runs (similarly, I'd like to write optional firmware to make it look like an X-box 360 controller or sony console controller, but I couldn't ship with that since I haven't done any licensing). It's not clear where those lines are sometimes (which is why this forum doesn't dispense legal advice, but I'm not even clear when situations NEED legal advice sometimes).
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Re: Kit vs premade; worth having both?

by lyndon on Mon Jan 21, 2013 6:54 pm

vputz wrote: it's far too fatiguing for production


Not to sound like a jerk, but I've always wondered what people mean by this. I have sat down and soldered literally hundreds of PC boards a day completely by hand. At one time, this was how all small electronics companies did it. I don't understand why it's now considered too tiring or too time consuming, or whatever. I can understand not wanting to do it, since it's boring. But as long as the time spent is properly accounted for by the manufacturing cost, it shouldn't be a problem.

It's strange to me, especially I see people going to great lengths to attempt farming out even a small handful of boards when it could be done easily "in house."

What am I missing?

(Note; this isn't intended as a slight against vputz, he/she just made me think of it again)

Anyway, to answer the question directly: I think it's always worth having a pre-assembled version. You never know how many people aren't buying it because they can't solder, don't have the time or simply just don't feel like it at the moment. This gives them an option.

As far as the pricing difference: you're on your own :-)
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Re: Kit vs premade; worth having both?

by vputz on Tue Jan 22, 2013 4:47 pm

Not to sound like a jerk, but I've always wondered what people mean by this.


Simple: It's tiring/time consuming/boring in comparison to other things I could be doing which would advance my cause faster. I know there's a better way, it won't take that much time and money to get it running, and my time is better spent either advancing new designs, working on infrastructure, or actually enjoying the fruits of my labor.

What I mean by "better way" is stenciling/reflow vs manual SMT soldering. I took both of Sparkfun's SMT classes (stencil vs manual) and left with absolutely zero doubt that stencil/reflow is the way to go, but also with absolutely zero doubt that even it would irritate me without a jig to stabilize my hands for component placement, so I'll try to build a "manual pick and place frame" (rail table with a vacuum pen and probably a USB microscope) and give it a go with the good old toaster oven/hot plate.

I can understand not wanting to do it, since it's boring.


No, that is the best reason. It's boring and time-consuming. Sure, I could gut it out and do it by hand, but pretty much every accomplishment in my life I've been proud of has originated from having a task that was too boring and finding a better, more efficient way to do it. Faffing about with rice-grain sized components and tweezers just isn't acceptable for production (maybe not even prototyping). If I didn't know it was a massive time sink, I'd throw my hat in the DIY Pick and Place scene, but honestly between the day job and anything resembling fun, I can only embrace semi-lost causes, not actually lost ones (it's not actually lost; I have faith there'll be a good OSS PNP machine eventually, but I have enough new things to learn right now).
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Re: Kit vs premade; worth having both?

by lyndon on Tue Jan 22, 2013 8:58 pm

Thanks for the well thought out answer. In my first job as an EE fresh out of school, I worked for a very small company where one of my responsibilities was to help the assemblers if we had a rush job and were backed up. So, the absolute tedium of soldering and testing a few hundred or so boards at a time was something I got used to a long time ago and has served to "calibrate" my level of tolerance for this stuff.

That said, your answer cleared up a misunderstanding: I include stencils & toaster oven reflow under my definition of "manual methods" and they are much faster than hand soldering.
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Re: Kit vs premade; worth having both?

by vputz on Wed Jan 23, 2013 3:32 pm

Aaah, sure; that would make sense. I thought you were proposing all-manual SMT, and honestly thought you were some sort of soldering god if you did THAT for mass production!

I'm still at the point in this where it's a hobby and I'll be lucky if it becomes self-sustaining much less makes anything resembling a profit... and as such I don't feel I can afford to spend any time which isn't actively building my skills somehow, so kits are where I'm at... unless I can find an excuse for assembled SMT. I'm... kinda looking for an excuse for assembled SMT :) I've wanted to do stencil reflow ever since the class, but MAN am I watching the DIY PNP scene. It won't be long, I think--I would guess the positioning side is basically done (heck, reuse a MendelMax or other 3d printer frame) and it's just the visual alignment and placing that's holding up the works. Even if a DIY PNP machine would be slower than me doing it, that's still time I could spend working on the next project. I didn't get into DIY electronics to do work that could be done by a machine!

Thanks for the input, though; I think I am going to push that direction. Once OpenRail is out of its "only to kickstarters" phase, I may go that route for a little jig, but I still have to set up a webstore and get my little project out of beta. Much of this is honestly for my own education; I was going through Seeed Studio for the first round of kits, and honestly they were pretty great to work with, but I didn't have contact with any of the buyers which limited my ability to communicate with the community, and I wanted to learn how to do the rest.
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