Modular Add On Unit To A Core Unit

[henrygr]

This topic has been bandied about before, but was dismissed due to a) the expense of interfacing, and b) the difficulty in removing anything analogue and leaving the AINs to there own devices.

I have been toying with the idea though, and was inspired by http://www.midibox.org/forum/index.php?topic=8054.0 to start a new topic on it.

I will tell you what I have come up with thus far.

a)Expense of interfacing- Using a 40 pin double row SIL header either end would be really cheap. All you would need then would be an IDE cable to connect them. If we haven't all already ripped our spare ones apart, then no purchase necessary! If we have, then the cost of one is only about €5. If or the sake of example we are using one whole muxed AIN board, that uses 32 pins for inputs, and two extra pins for Vs and Vd, leaving six pins on which to get around the problem of........

b)The difficulty in removing anything analogue and leaving the AINs to there own devices- Came up with two workarounds. One, rather complex idea of a muliplexing relay switch that would send the AINs to ground when the cable is removed by using the spare pins to act as a switch. Rather expensive, and it seems that these parts are not exactly available of the shelf for guys and gals like us. (Side note- I have come to the conclusion that when googling such things, and GlobalSourcesChina comes up on the first page of results, I am in for a tough time in finding a feesible solution. From here-on, I am calling this "The China Syndrome").

The second idea utilises banksticks. I have not programmed or used them yet, but I was thinkling that if it was possible to embed a bankstick in each modular unit, one could then set the AINMuxed number of inputs in the core to 32 for normal operation. That way the second multplexer is not regarded, and you could tapdance on the pins without getting any jitter. The only difficulty here is that you have to learn to tapdance. However, when you connect the unit, you could put in an additional DIN switch that would call the bankstick to be loaded or unloaded, hence an on off swith for the unit.

What do you think?

[Jidis]

Henry,

Not sure if it's the exact same scenario, but for pulling down random analog pins, I've been putting 8-way DIP switches on my Core. I actually started off using a dual row jumper block with a row hitting the analog lines, and the corresponding row all ground pins. That was a dual purpose header, where I could pull any or all 8 lines off to pot(s) and keep the jumpers on the rest, but that requires weird cabling to go out from the header to the pots. Now I just link all the pins on my analog header block to a similar setup with one of those multi-switch DIP switch things, with one whole side tied to ground. The wiring was pretty easy, as I just soldered a strand of wire across the base of the switch on one whole side for ground before installing it, so it really only needs the one pin at the end tied to ground. The other side can just sit inline somewhere with the analog pin paths (hope that makes sense).

I guess you could do the same with the lines headed to a mux chip.

Here's the older one with the jumpers:

And the new DIP one:

- The "shorting" wire is actually under the switch, on the top of the board.

(the analog inputs are that 2x5 header over on the left)

Take Care,

George

PS- Right now, I'm trying to do a Core on a piggyback daughtercard, which will mount to the main (pot/light/switch) board using a 2x8 header block on one and a female socket on the other, along with a standoff or two on the other end. If it works I may start making multi-layer projects with small boards, that "squash" together like that. Imagine a five-deep stack of MBHP boards, with standoffs, locked together like a small rectangular "brick" ::) ::).

[henrygr]

Thanks for the info Jidis. I must say though, I love your photograps better when you can see your feet...he he.

I forgot to mention a switch I pulled out of a Serial Port box a while back. You know the boxes i'm talking about- the pre-USB days when the change over switch for a printer between two PCs cost a fortune. Well they can be found still, and cost only a couple of Euro. No, although the parallel post is only a 25 pin connector, the switch in it was actually a 2 pole 32 way single throw switch (did I get that in the right order?) So there is a simple cheap solution. You can then use the metal box it comes in for growing seeds in, throwing at your neighbours dog (with a big piece of elastic attached so that it coms back to you, but wathch your head) or even, come to think of it, a MIDIbox enclosure!

I like the bankstick idea best, as it involves no mechanical parts though. I program in C, but am a loss of where to start/what the hell it actuallly does. Can someone point me to a "Bankstick For Dummies" page?

Thanks.

Will report on my findings.

Oh yeah, Jidis, where do you upload all your photos. It's like you're the MIDIbox roving reporter with all the pin ups you do. They are excellent!!

Mark.

[Jidis]

Ladies and Gentlemen....... This just in:

Couldn't help it Mark. It was on a shelf right in front of me. ;D

I just throw the photos on this thing called Photobucket (http://www.photobucket.com/). They show up in an "album" and you can copy/paste a link to them in places like this. I don't know if it's a good or bad site, it was just the first one I found when looking for a free place to host jpgs. Seems to work OK with little mess or ads. If it dies I guess I'm doomed though. 8)

Take Care,

George

[henrygr]

;D ;D ;D ;D ;D ;D

LOLOLOLOL

S**t. I just laughed for five minutes solid. Think i'll have a can of beer now, it's like being at the pub.

Anyways, went searching after my last post and got this https://www.google.com/accounts/ServiceLogin?service=pages&continue=http%3A%2F%2Fpages.google.com%2F&ltmpl=yessignups&passive=true

100mb free web space from Google with page creators. Check it out. If you need a gmail invite, PM me.

Mark