There’s quite a bit I could ramble on about for this one – but i’ll just post a load of photos instead.
This thing’s TINY – those ‘legs’ are just 1.6mm wide….
The main arch is just over 2mm wide.
Those LED’s are 1.5mm x 1.5mm
And, importantly – I’ve found two manufacturers!
JLCPCB can get a sample of 10 units done – But they’re not ideal…They can’t fully mill out the PCB
PCBWAY CAN fully mill out the PCB – AND populate it with LED’s for me AND, I’ve fully costed for a batch of 1000 – it’s better than I’d expected all up!
More about the JLCPCB – Here’s a larger ‘outline’ of the board i’m getting done
I’ve used something called ‘mouse bites’ – where you preforate the PCB along the part you want to ‘snap off’ –
It’s just a whole bunch of drill holes – 0.2mm here spaced about 0.25 apart edge to edge (so about 0.425mm centre to centre)
I’ve chosen this odd looking way of doing it – a few reasons
- It makes a square just over 2cm x 2cm – so it’s ‘easy’ for them to handle
- JLCPCB can only mill out PCB features > 3mm apart
- Their standard mill is 1mm diameter – so my inner radius are now 0.5mm or larger
- When the board sits inside the pocket in the next – the inner surface is the most important mating part – if that’s slightly over, it knocks out the whole alignment – so it’s the one I need milled ‘propertly’
- The outer arch is covered over by the SLA printed insert , it’s finish is far less important and i’ve made a 0.2mm all round ‘clearance’ in the final design
I’m hoping that I can quite easily ‘snip’ off the excess PCB bits – I’ve ordered 10 so can afford to mess a few up
So far my Bill Of Materials to make this sample adds up to over £100 :-O – 3/4 of that’s on the SLA printing and PCB’s mind. Armed with a Dremel (if I can ever find it) i’ll be able to mutilate most of the prints I’ve ordered to wedge in the first 10 PCB’s
Hoping to get at least 2 full sets working out of this lot, then i’ll figure what’s the interest in them and maybe make some more!
Finally, a real shout out for the customer service at JLCPCB and PCBWAY
JLCPCB allowed me to iterate and chatted by email four or five times till I got a PCB they could make, it’s such a small order right now but they do have a customer for life (and i’ll get the C64 boards done there, maybe a few more speccypi’s also). I think that my reading their capabilities and re-designing every time based on what they said must have helped them as much as they helped me.
PCBWAY – again, fantastic. My first thoughts were to go flexible due to the limited hole diameter – (1.6mm) – BUT, now I can go FR4 (i’ll cover in another post) they were much more cost effective. My first thoughts on QTY’s are maybe getting 1000 PCB’s made and assembling 500 of them, I can ‘just’ about self fund that if there’s demand, But it’s increasingly looking like i’ll need to do a mini kickstarter! – hopefully I can co-ordinate something with the main team so mine starts just as theirs is finishing – we’ll see if I can stop procrastinating that long