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I don't get it. What are you showing the boards for...?
Because PC boards are an art form, and I'd like for some others to
post their boards, styles, colors.
Here is my most recent one. Nothing spectacular I guess but it turned
out well, worked first time and only took a couple of days.
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http://ee.devereux.me.uk/203001-01.jpg>
Bottom right quadrant is a 8 channel 0-10V output. An ADUC7021
microcontroller, with a pretty good reference and 12 bit DAC, generates
the 8 values in sequence. A CMOS switch "demultiplexes" this onto a set
of capacitors to hold the voltage. Opamps then boost this 0-2.5V to
0-10V.
The rest of the board is a USB to RS485 adapter and a boost power supply
generating 12V from the USB.
In fact the RS485 carries modbus traffic, and the microcontroller snoops
on this traffic and extracts the relevant values for the analog
outputs. When the USB is disconnected, the microcontroller takes over
(reversing roles) and becomes the modbus master. That bit was a PITA.
It's black because I thought it would look cool, but the assemblers did
not like it, they had to adjust the sensor on the P&P to get the
conveyor to stop the board in the right place or something. And you
can't see the tracks very well.
It is two-layer, routed basically single layer style on top and
groundplane underneath. Barring a couple of short hops I expect.
It goes in one of those extruded style aluminium enclosures, that's why
the funny cutout on the right, to stop the board moving around in the
case.
Thanks, (I was going to take a pic of an old circuit, but too many
screws and too little time today.)
I'm guessing you won't do the black pcb again unless you need it.
(It seems for anything I make, the mistakes always stay longer in my
memory, than any successes.