7 Dec
2021
7 Dec
'21
3:27 a.m.
I've used PCBCart.com to have thousands of boards produced. Mostly with
gold fingers
They've done a good job with the boards, though they're mostly two-layer
and not overly complicated.
You just tell them how many gold fingers you want (and if you get it
wrong, their design check will clarify with you).
You also can specify if you want a chamfer on the edge and the degree of
that chamfer
Things weren't good when the tariffs were in effect and the shippers
didn't understand what the PCB tariffs applied to and what they didn't.?
That added a lot to the cost.
That's back to normal now but prices are up (like everything else).
Todd
On 12/6/2021 5:45 PM, Mike Katz via cctalk wrote:
One of my zillions of projects is to redesign Oscar
Vermilion's
PdDP-8/I using the Raspberry Pi Pico board and these LEDs.
I would use one core for SIMH (the PDP-8 simulator) and one core for
the Incandescent Emulation.
Right now I'm too busy finding parts for my real PDP-8/E and getting
it running.
Think of the addressable LEDs and LEDs with the shift register built
in ?.
When you are ready for a redesign, you might consider it for a cost
reduction.
If I may8 ask a question.? I have never had boards made before. How do
I find a good board house that is reasonable and how do I specify the
board especially for the PDP-8 Omnibus which should have gold fingers
on the edge connectors?
Thanks and good luck,
????????????????? Mike
On 12/6/2021 2:07 PM, David Bridgham via cctalk wrote:
On 12/6/21 10:36 AM, Mike Katz via cctalk wrote:
Each LED requires 24 bits of data.? That would be
3,456 bits.? The
WS2812B has a 300uS low start indication and 1.25 uS per bit. That
would mean it would take. 4.62mS to update the all of the LEDs.
If I'd known about those when I designed my boards, I might well have
gone that way.? They're surprisingly inexpensive even.
Instead, I ended up using a 16-LED driver chip that basically looks like
a shift-register.? I clock in the 144 bits (just on-off, no fancy
tri-color LEDs I'm afraid), toggle the latch signal, and there it is.
If you want to support more indicator panels, it's just a longer shift
register.? I then added RS422 driver chips for noise immunity and there
I was.
Dave