Had to admit, the failure of the Beta 9 got to me a little bit. Took me a couple of days to take stock, stand back and think.
After much thinking, about life, being married, kids and generally having to work hard at a day job, remembering about that one time where that bloke ripped you off, Postulating how things can build up and get to you to the point where you just think that getting screwed and having your balls in a vice would be more preferable………..
You can come to yet another epiphany!….Screw it and put the Balls, in a vice.
I present to you……..The precursor to the release candidate for the production version….Err
Been a busy few weeks here at Bleugh.Biz industries, working ridiculous hours at my day job, keeping kids from murdering each other during the evenings……But, i’ve been getting some good tinkering time in.
Some very good progress has been made! – and this is the board that’ll hopefully, finally, once and forever physically fit perfectly
Some Notable changes
Balls! – A revised J15 connection method that’ll provide a simple and very robust connection method
Spacings – The holes for the LED inserts have been altered a little to allow easier assembly. It’s still mildly fiddly but easy enough.
Fixtures – The J15 are has now two horizontal slices cut into it – this provides a spring mechanism for the balls. it helps to PCB distortion locally without warping all of the board from Next PCB to inserts
Holes – The whole board is now held with press fit type connection. The two screws holding the Next PCB are removed and replaced with two new ones. this holds the Blinkenator board to the next PCB and the Next PCB to the case. The two holes for the screws have been changed to 5mm!
Positions – The JST style connectors have been re-located and changed from Right angle to Vertical. Now the board’s mounted above the next board there’s plenty of space underneath. The path from the Arduino USB connector is now also free so you can tuck a cable into the board permanently
LED’s – Moar Bling! Each insert location now has a LED colour on the main board. No real purpose other than to look great and provide the end users with some assurance that the board is powered up when they do their first tests with a USB cable outside of the Next
ESP-01 – CPU_RST has been changed to a JST style connector to make ease of fitting. This whole feature is still highly experimental and may not make it into final production (if it doesn’t work, there’d be no point!)
Inserts – There’s now a 0.56mm gap between the jumpers – to fit a 0.6mm wide PCB!. makes a nice snug fit. and easy also to work with – simply trial fit once when you receive your board, that’ll loosen them up. remove and re-fit into the Next
Jumpers – Lots of experimental jumpers! GPIO to arduino, TX/RX to arduino, DB+ integration enabling / passthrough…….and some secret sauce also
THICKNESS – The board’s back to a phat 1.6mm thick. this provides significant stability to the jumpers that hold the inserts in place. Much easier to repeatedly get them soldered straight when assembling
Components – The whole board’s been rationalised for component price – and where possible using @JLCPCB’s BASIC library – that saves quite some amount in production prices as non Basic items incurr an engineering fee per component. Previously 3/4 the components were Extended, now 3/4 are Basic!
Silkscreen – Tidied up and made a bit more slick……..
I’m sure there’s a few more changes i’ve missed, but that’s the important stuff.
Where from here……….IF this last board plugs in, fits well, i’ll be sending out to the key Dev team. I can then kick back, relax a little and start again playing with the software side of things, Both Next side and Arduino side!.
I’ll eventually also need to consider switching over the whole board to SMT, or as much as possible. I’m not that daunted by this as there’s quite a number of ways this can be achieved, including just putting the 32U4 straight on-board, or considering changing the micro type entirely. After all, the main reason i’m using a 32u4 is that it’s cheap, Arduino compatible, has USB built in. All those things give a great ‘dev board’ capability that people can use to simply plug in and tweak!
With a successful 2nd Kickstarter – The Spectrum Next will have between 8,000 and 9,000 users.
Lets Dream a little and imagine a Bright world where all the users have a Super LED Blinkenator 2000 installed….
9000 users = nearly 40,000 inserts to be made!.
lets say just 10% want the blinkenator, I still have to make nearly 1000 of the things.
I’ve been researching a little and identifying bottlenecks to SUCCESSFULLY produce and deliver my board in those quantities
There’s some scary numbers!
So, I’m now pressing forward with TWO designs. one design, the one you’re all familiar with, suitable for small time production in small batches here and there on my weekends, only ever endeavouring to sell maybe a 150 units ever
and the second, a ‘mass produced’ item that requires minimal ‘hands on’ time from me to deliver, but will require some significant outlay up front.
The pictures above are a first run result of my Design For Manufacture for the inserts….A different injection mould, possibly 2 parts, maybe 1 and using a flexible PCB!
some key notes……..
Advantage – no connector soldering needed on my part – currently I’m soldering 16 cheap ‘bridges’ to each main board. with this insert, someone will be soldering 8 SMT FPC style connectors
Advantage – it’s likely that this design will be easier to make ‘injection moulding’ manufacturable. the existing design is tricky, but not impossible
Advantage – FPC connectors are a bit more reliable and easier to use than my bridges for the end user
Advantage – FPC / flexible PCB ‘legs’ on the inserts will mean a little bit easier installation by the end user
Advantage – Uniformity of Light – This type of construction allows for a much thicker ‘top layer’ – which will diffuse the light far more. Also, more of the insert will be better lit up ‘from below’ rather than from the side that i’m currently doing.
Disadvantage – FPC connectors are more expensive
Disadvantage – Flexible PCB’s are more fragile
Disadvantage – Flexible PCB’s are more expensive than FR4 for small quantities, so prototyping ability is very limited. at The quantities I need though, there’s not that much difference
There’s more i’m sure, once the final numbers are ready, I can see if a kickstarter makes sense, it may not be financially viable if the whole thing needs to be sold at £80 each……
if I can get closer to that £50 mark, then who knows!
Had a little bit of a play with the daughterboard to see if there’s any possibility of putting a ‘push push’ SD card inside…
Unfortunately it isn’t without chopping at a couple of supports inside. I’m trying to keep my Next case fairly minty – untill it’s possible to get another, i’m going to avoid this mod.
The reasons it won’t fit – The case was designed with two ‘helper’ guide rails for the SD card – shown in yellow in the images above. Those rails stop any push-push mechanisms from working – there’s just not enough mounting depth for the card reader.
Now, if someone were prepared to snip those rails off….then it’s entirely possible to knock up a new daughterboard……I’ve already done most of the EDA before I thought to take the next apart and check 🙂