ComputerVoltageSources

I may want one of these 16 analog input boards for my PSIM for a 
sequencer so I designed an ExpressPCB mini-board. For those of you 
that don't know, this is a fixed-size set of 3 quicks with no solder 
mask or silk screen for $51.  It makes small runs of PCBs pretty 
affordable.

I put the design file "I2C Analog-Digital Design Files 4-10-07.pdf" in 
the files section.  I put 4 of the PCF8591 parts with 4 analog 
channels per part for 16 inputs.  There is no over/under voltage 
protection as it is intended to directly interface to 16 
potentiometers.

Andrew - I know you are trying to do something with 16 switches so I 
added two MCB23008 parts for 16 digital inputs/outputs. Maybe this 
will be easier than wiring up your parts.

Regulation is from +15 volts through a 78L05.  There is very little 
current draw from these parts so the L version should be sufficient.

I added two MTA power connectors so this board could daisy chain with 
either the PSIM or LCD-Support PCB.  I put an extra 3 pin MTA-spaced 
set of holes so wires could be soldered directly to +5, +15 and 
ground. Connection to a PSIM is through a two-wire interface to 
connector J3.

I'll leave it up in the files section to take any feedback before I 
order mine.  I would appreciate if someone would give them a quick 
look-over. I've used both of these parts on my AtomPro so I know they 
work. I haven't used all 6 together but don't see any issues.

For PSIM owners who want a sequencer, I have a 16 step program on my 
web page.  It already interfaces to a single PCF8591 so it wouldn't be 
hard to modify. I use the eeprom in the AtomPro28 so that would have 
to be modifed although you could replace the AtomPro24 with a 
AtomPro28 to get the non-volatile storage (That's what I did with my 
PSIM).  If you add John's LCD Support module then you'll also get MIDI 
and a display for a user interface. Connection to the PSIM is through 
a three wire interface to connector J5. I have videos of my sequencer 
LCD also on my website.

Disclaimer - I don't sell boards and I'm not in that business. I have 
previously made parts available like my A440 generator and the LCD 
Support module with John only to have email interest go unanswered 
after buying parts. I will put the design files up for anyone who 
wants to order some after I have verified functionality.  Maybe two or 
three of you can get together to pool a single order. The ICs are very 
inexpensive so it would be quite affordable.

Dave