Hello,
I want to control a dust-collector with a PIC, so that at each power tool I
hit a push-button which:
1) turns on the dust collector
2) pulses a solenoid on an automatic blast-gate
3) checks to make sure the gate opened.
I have no problems programming the PIC, but the interfacing questions are
another issue (!).
I have six stations, each of which will have a switch. My PIC has 12 I/O
lines, so I want to multiplex the triggers together.
My basic idea was to do something like:
1>——–X———–|———-|—————-
2>———|———-X———-|—————
3>———X———-X———|————–
4>———|———–|———-X————
5>———X———-|———-X————
6>———|———–X———X————
7>———X———-X———X————
| | |
A B C
Where ‘X’ means a connection. Then pressing switch number ’5′ would make
the ‘A’ and ‘C’ lines go high, for instance.
This seems simple, but my question runs along the lines of:
1) How do I make sure the non-triggered (A,B,C) lines stay low?
2) Is there a cheap and simple IC to do this part of things? (for output,
I’ll be using a 4028 to unscramble the BCD into separate output lines)
3) How do I guarantee the triggered lines go high (i.e., might there be a
problem of one going "higher" than the other)?
I’ll be using a PIC16C84 to do the main logic.
Thank you for your input (no pun intended!),
Ron
—
The opinions expressed in this message are my own personal views
and do not reflect the official views of Microsoft Corporation
- Hide quoted text — Show quoted text -
"Ron Aaron" <ron.aa…@worldnet.att.net> wrote:
> Hello,
> I want to control a dust-collector with a PIC, so that at each power tool I
> hit a push-button which:
> 1) turns on the dust collector
> 2) pulses a solenoid on an automatic blast-gate
> 3) checks to make sure the gate opened.
> I have no problems programming the PIC, but the interfacing questions are
> another issue (!).
> I have six stations, each of which will have a switch. My PIC has 12 I/O
> lines, so I want to multiplex the triggers together.
> My basic idea was to do something like:
> 1>——–X———–|———-|—————-
> 2>———|———-X———-|—————
> 3>———X———-X———|————–
> 4>———|———–|———-X————
> 5>———X———-|———-X————
> 6>———|———–X———X————
> 7>———X———-X———X————
> | | |
> A B C
> Where ‘X’ means a connection. Then pressing switch number ’5′ would make
> the ‘A’ and ‘C’ lines go high, for instance.
> This seems simple, but my question runs along the lines of:
> 1) How do I make sure the non-triggered (A,B,C) lines stay low?
> 2) Is there a cheap and simple IC to do this part of things? (for output,
> I’ll be using a 4028 to unscramble the BCD into separate output lines)
> 3) How do I guarantee the triggered lines go high (i.e., might there be a
> problem of one going "higher" than the other)?
> I’ll be using a PIC16C84 to do the main logic.
> Thank you for your input (no pun intended!),
> Ron
> —
> The opinions expressed in this message are my own personal views
> and do not reflect the official views of Microsoft Corporation
Try diodes and load each input with a 1 k resistor pull the diodes
up (use germaniun sig diodes 0.3 volt drop 1n914 e.g. y using diodes
simple input closed contacts and direct signals to your matrix with diodes
good luck
elliott
bi…@voicenet.com<elliott>