• Weeks 275-276

    9 April 2018

    My time over the fortnight around Easter was spent on some Selworthy R&D, wrapping up a Foxfield production run, and continuing various pieces of hardware R&D.

    Over on Selworthy, I finished up my first pass at the stand-alone library I’ve been working on and delivered an end-to-end test of its output. In week 276, I moved onto R&D around HLS video streaming – not only the various FFMpeg incantations to generate it, but also exploring how much of our client we’d have to replace to implement it, and how best to retain feature parity. The answer is that the key features will transfer over fine, but we’re probably going to have to replace one particular video library, and so my continued scoping – for now – will be about delivering that feature parity.

    After various pokes and prods, my PCB vendor in China delivered a batch of front panels that were correct – following some production delays – and that meant I could box up a Foxfield/Longcrag production run and send it to Thonk.

    This also confirmed my new approach to panel manufacture is successful, and that opens up some of the otherwise tight margins on future Foxfield products – which are nearly ready to offer up, I think.

    Over on the 16n project, we saw our first prototype aluminium panel, which looks great. The next move is to make a full prototype of this version – version 1.25 – and confirm everything fits as expected. I think fit/finish will be fine; the key thing is confirming sizes of standoffs and screws. Once that’s done, we’re on to looking into manufacture routines.

    As part of that, Brendon shared some calculations he’s previously used around costings for hardware runs, which were really illuminating, particularly for understanding how much that looks like ‘profit’ is, in fact, really just margin and contingency. It’s helped me understand what a particular idea I currently have might involve, too.

    I also continued work on a small Longcrag prototype that I’m designing for manufacture. Will this ever happen? I don’t know. Why do I keep spending time on it, then? It’s a good question. It’s certainly intellectually interesting. And I’m learning a lot. It’s definitely not hit a NO GO condition, though it’s getting nearer to that point, perhaps.

    On this DFM prototype, I assembled a test board. This is significant for a few reasons; notably, it’s the first board designed around the Silicon Labs chip I’ve chosen to use. That chip happens to be in a QFP48 package, which is about at the limits of what I’ve previously hand-soldered and, sure enough, it turns out my hand soldering is possibly not up to the job. The idea is to build up this prototype, and flash it via the SWD interface I’ve broken out on the board. That would prove that my layout for the chip and SWD interface were correct.

    I spent a lot of Friday trying to do this over a JLink, with no joy. It’s not clear why, however. I patched a minor mistake on the board, tested the pinouts with a multimeter; I am pretty sure the board is correct. But it still could be a manufacturing fault – ie, my soldering. My plan for next week is to use a stencil, solderpaste, and a hot air reflow station to try to make a more definite connection between the QFP48 and the board. If that doesn’t work… I might be throwing my hands up in the air, into a NO GO configuration.

    Why would that be a NO GO? Because it’s tiring, and I’m heading towards a point where I’m no longer learning or moving forward; all I’ve got to is a sticking point, and maybe going around would be better. But we’re not totally out yet. So another afternoon on this, still. I remain hopeful. Of course, if this is a GO, we open a whole new set of GO/NO GO branches – finishing firmware, for starters, and then trying to work out if there’s even a market for this.

    I also managed to fit in some more social engagements. I spent a nice lunchtime with Nick and Timo at Playdeo. Mainly just a catch-up with old colleagues, friendly chat with peers in the industry, but also good to talk shop with other people working between technology and design, gain some perspective, and tickle each others’ imaginations. Good for the soul.

    And on Friday, I got over to a BBC R&D event exploring the artistic application of voice assistants, pairing technologists with musicians and sound artists. Some familiar and new faces, some great performances, and good chat afterwards. Also good for the soul.