Any sense in "hybrid" (partially preassembled) kits?

[vputz]

I've done a through-hole kit which, though it has a small target audience, works fairly well (it's a HID device using V-USB). But I think it would be more effective if it used the ATMega32u4 with its native USB capability.

Unfortunately, the 32u4 only comes as an SMD part. And if I'm going to use an SMD part, I almost may as well buy cheaper SMD components for everything, cook the boards on a hot plate, and sell assembled/tested devices.

But then it's not a kit, and I like kits. Kits are cool.

So... is there any sense in partially preassembling boards (placing the hard SMD components like the ATMega and the micro-USB port, say) and leaving the rest as through-hole kit components? Would that be the best of both worlds or the worst? Anyone with numbers having offered both types, fully-assembled and partially-assembled?

[adafruit_support_mike]

I think it's a good idea.

First, SMD components may be cheaper, but placing and soldering them costs time and money. I doubt you could sell a fully assembled and tested product for less than a kit.

Second, through-hole soldering and SMD soldering are different skills, especially if you use some of the smaller packages like TSSOP or QFN. If 'can be assembled by the average mortal' is one of your design goals (and it's a darn good one), taking the difficult and high-chance-of-failure work off the customer's shoulders is a good thing.

If you get right down to it, that's the same reason we sell people a professionally-made PCB rather than expecting them to mask and etch one for themselves.

Producing a kit is a service. We do the time consuming and cheaper-in-volume stuff so our customers can do the fun and best-handled-individually stuff. If setting SMD components is a hassle your customers don't want to deal with, by all means do them the service of taking that unpleasant job off their hands.

Third, this:

But then it's not a kit, and I like kits. Kits are cool.

is composed of pure awesome.

That's all the explanation you need. Anyone who doesn't say, "yeah!" to that won't buy a kit anyway.

[vputz]

Fair point. I maybe should have thought of that anyway before I ordered my prototype board with all-SMD components on it... urk. But hey, always wanted to learn SMD anyway. Except that even on the "smd" version of the board there are some through-hole bits (couldn't find a source of SMD DB9 ports that I felt really good about).

So what this may turn out to be is a board where the "arduino" portion is populated so I can flash and test it (plus put the 32u4 and the micro-usb port on, smd-only) and leave the rest for the hobbyist. Maybe. Hmm; that'll take a think or two. But I may just make two versions and see who buys what.

(although that has me doing a little more than half and the user doing the rest; this is sounding like the apocryphal Betty Crocker "having the consumer add an egg makes it seem like they're doing enough work to be invested" story)

(which may not be such a terrible thing)

[moorejl57]

If you do go with the 32U4 based solution, what are your thoughts on the VID/PID issues for the bootloader? I have always designed with PIC uC and Microchip has provided me with a PID for use with their VID which is very generous. I don't believe that Atmel is doing this at this time. I want to make a open source Arduino compatible board product but haven't figured this one issue out yet. Getting your own VID is now up to $5000, which is a staggering sum for small scale manufacturers.

[vputz]

Funny you should mention; I was just wrestling with this. Curiously V-USB has a VID/PID for OBDev industries, but if you go with the 32u4, it's a bit murkier. You could also ship without a VID/PID or point out it's not encoded and the user will just use an "illegal" one, but that's not great either.

There is a sort of solution, of the form "it's not actually legal, but if you fly under the radar..." OpenMoko bought themselves a VID, but there's no way they'll go through 16 bits of PIDs, particularly since they don't make hardware any more. So, as long as you're producing open-source hardware and the source is available, they are giving out PIDs. This is pretty amazing of them. I don't think it's strictly legal (in the sense that the USB Ministry of Control disallowed sublicensing a vendor's VID/PID), but since the projects are open source, I imagine it's confusing enough and small enough volume they won't bother with litigation.

Started designing a "SMD the 32u4, through-hole the rest" board today, curse you Wish I'd sent that to the prototypers first.

[adafruit]

Thanks for that reference to the Openmoko page, its great!