Multiple Buttons on a Single Analog Input

[t vago]

I'm working on integrating your code into the 1.86tav MPGuino software. Currently, I'm having issues with getting the software to immediately recognize a keypress. (I am trying to retain long-button-press functionality).

[nickdigger]

The keypress should be recognized when the key is released, and returns to "buttonsUp" -- provided it has passed the debounce period (nominally 29ms in the posted code, but a lower value might work too), For a quick keypress, this should appear to be instant, since the timer2 ISR is firing every 1msec. You could probably also trigger it, after passing the LongPress threshold, and not wait for buttonsUp.

The one difference i can think of, is that an extra variable, buttonGood, is now required. It wasn't needed before, because PCINT_vect was detecting pin changes on that port.

[t vago]

My code has the button detection in the ADC interrupt handler, operating as you had described, nickdigger. My FIR filtering routine and my analog pin channel switching routine were not playing very nicely with each other, which interfered with the analog button signal timing, which caused the software to recognize all keypresses as long keypresses. I stripped out the FIR filter for now. Currently working on reintegrating FIR filtering.

In the meantime, both short- and long-button press functionality is retained.

I got the code to work with a 5 button configuration. This should allow for adding something along the lines of a Parallax 5-position switch.



I also changed the code to more easily accommodate recognizing more than 3 different buttons.

[nickdigger]

Maybe you can selectively turn the filter on/off for different ADC channels?
Also, the Arduino code for that Parallax switch indicates they are using 5 digital inputs, not one analog. I haven't taken a closer look at the specs to see if analog output is an option, but their page only mentions "a 10k resistor", which doesn't sound promising.

[t vago]

Originally Posted by nickdigger

Maybe you can selectively turn the filter on/off for different ADC channels?

Thought about doing that - that'd introduce more complexity, and I'm not sure if that's such a good thing for an interrupt handler that must fire off fairly quickly. Might do it anyhow, though.

Edit: On second thought, after reviewing the AtMega128/168/328 datasheet, might just abandon the FIR filter altogether.

Originally Posted by nickdigger

Also, the Arduino code for that Parallax switch indicates they are using 5 digital inputs, not one analog. I haven't taken a closer look at the specs to see if analog output is an option, but their page only mentions "a 10k resistor", which doesn't sound promising.

Looking at the switch hardware in my hands (yes, I bought one from RadioShack), I notice that it has just a bunch of SMT 10k pullup resistors. That's your digital signalling. Remove them, and you have something that is usable. Heck, you might even be able to use the switch without removing the resistors - it'd just be a matter of doing some signal analysis with the pullup resistors added into the analysis.

[t vago]

Added Parallax 5-position switch support. Since the Parallax 5-position switch does not do simultaneous left + right button presses, I've defined the up position as left + right.

[nickdigger]

So the Parallax does have analog output, as well as the 5 digitals? Too bad it costs so much.

[josemapiro]

Originally Posted by nickdigger

So the Parallax does have analog output, as well as the 5 digitals? Too bad it costs so much.

This here is different but cheaper, operation must be same.

5-Way Tactile Breakout Board Jaycon Systems LLC

José Rodrigues

[t vago]

Originally Posted by josemapiro

This here is different but cheaper, operation must be same.

5-Way Tactile Breakout Board Jaycon Systems LLC

José Rodrigues

And the schematic appears to show exactly the same pull-up resistor configuration as with the Parallax switch. This should work with v1.86tav, with no code modifications.

[OldSubi]

Hi Just wondering if this thread is still going and if I can ask a question about my car MPGuino Project? ....When I understand things a bit more!
Its about using 5 switches to replace old trip computer in my 1984 car.
current functions are Clock, Range, Trip, Timer, & Reset I'll post a Photo if I'm not Hijacking your thread.
Thanks