Standard Approaches to Simplistic User Interfaces

J

Thread Starter

Jim English

I have one pushbutton and one LED as my user interface and I would like to
be able
to differentiate 6 different inputs and 6 different ouputs. I would like to
use a
standard/customary solution ( other than Morse code) to the problem which
specifies pulse duration etc. Can anybody offer any suggestions. Thanks.
Jim
English
 
M

Michael Griffin

The pushbutton might be difficult. I have seen servo drives though
which used one LED to signal five different fault conditions by simply
flashing from one to five times, pausing, and then repeating. I didn't find
this very difficult to understand.

Someone suggested using an analogue input with a rotary switch
instead of the push button. If the hardware design is not already fixed,
this might be an idea. There is a simple type of analogue input which
repeatedly charges up a capacitor, and then measures (with a counter in the
MCU and a comparitor circuit) how long it takes to discharge it (I forget
what this method is called). It is not very accurate, but it should be more
than good enough and you won't need an A/D converter.

Another possibility is to flash the LED whenever the push button is
held down. The user just holds the button down for a desired number of
flashes, and then releases it. After you release it, it pauses and then
repeats the code back to you and then stays on until you press the button
again to confirm your selection. If you don't confirm the selection within a
certain time-out period, the LED goes out and your command is discarded.


**********************
Michael Griffin
London, Ont. Canada
[email protected]
**********************
 
J

Johan Bengtsson

One button and one led? I hope there is a good reason..., well...
As for output:
off
constant on

the rest could be built in the followig way:
one long flash, followed by 0 to as many as you need short flashes
a pause
repeat the sequence

as for input:
I have a cd player with a remote control on the earphone-wire one
button performs the following tasks:

one short push: start/stop
one long push: turn off, a beep is heard when the time is enough
two short pushes: skip forward
three short pushes: skip backward


the two and three pushes have to be within some amount of time, like
double klick.

Maybe this scheme could be expanded to meet your needs, the led could
perhaps be taken from its normal duty of displaying outputs and instead
assist the input when the button is pushed.


I hope this gives some new ideas...

Johan Bengtsson
P&L, the Academy of Automation
Box 252, S-281 23 H{ssleholm SWEDEN
 
M

Michael Griffin

The pushbutton might be difficult. I have seen servo drives though
which used one LED to signal five different fault conditions by simply
flashing from one to five times, pausing, and then repeating. I didn't find
this very difficult to understand.

Someone suggested using an analogue input with a rotary switch
instead of the push button. If the hardware design is not already fixed,
this might be an idea. There is a simple type of analogue input which
repeatedly charges up a capacitor, and then measures (with a counter in the
MCU and a comparitor circuit) how long it takes to discharge it (I forget
what this method is called). It is not very accurate, but it should be more
than good enough and you won't need an A/D converter.

Another possibility is to flash the LED whenever the push button is
held down. The user just holds the button down for a desired number of
flashes, and then releases it. After you release it, it pauses and then
repeats the code back to you and then stays on until you press the button
again to confirm your selection. If you don't confirm the selection within a
certain time-out period, the LED goes out and your command is discarded.

Michael Griffin
London, Ont. Canada
 
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