multiple inputs

SY

Hi,

I need to create a simple circuit that can receive 6 inputs and for each one, light a load for a number of seconds and turn off.
Doing this in a linear fashion is simple. But I don't know how to keep listening to the other buttons while one is executing the "turn load on - wait - turn load off" sequence.
All inputs are controlled by one stamp but the displays are not related and need to be readily reactive unless the light is on.
Is there a listener object that can constantly monitor the inputs regardless if a load is on or not?
Can anybody suggest a way to program this?
Appreciate any help I can get.
Thanks.
SY.

Mike Green

You need to overlap the testing and the timing. Keep a count for each input indicating how many seconds or tenths of seconds or whatever that light still has to stay on. Each time through the one loop, check the inputs one at a time. If the input is on, set the corresponding count to say 50 (for 5 x 0.1 sec). Then check the counts. If a count is non-zero, turn on the load, then decrement the count by one. If the count is zero, turn off the load. After you've handled all the counts, PAUSE for 100ms (or whatever you need), then repeat.

I think the "inPins(i)" thing will work. I don't have a current PBasic manual handy to make sure.

maxInp con 2
count    var byte[noparse][[/noparse]maxInp]  ' or whatever you need
i            var byte
inPins    pin 0
outPins  pin 2

             for i = 0 to maxInp-1
             input i+inPins    ' initialize the inputs
             low i+outPins    ' initialize the outputs
             count(i) = 0      ' initialize the counts
             next i
theLoop for i = 0 to maxInp-1
             if inPins(i) = 0 then skipPin
             count(i) = 50    ' if on, set count to max
skipPin   next i
             for i = 0 to maxInp-1
             if count(i) > 0 then makeOn
             low i+outPins    ' if count zero, turn off
             goto doNext
makeOn high i+outPins  ' if count > 0, turn on
             count(i) = count(i) - 1  ' and count down
doNext   next i
             pause 100        ' this give approx 5 seconds on
             goto theLoop    ' do it all again

Tommy Bot

This advice does NOTHING to attempt syntax but only explains logic flow. You need to understand that the BS2 does not multi-task, nor does it have an interrupt. This is why the Stamp does not look for the next button press until the current lighting sequence is complete. You need to “time share” and use a lot of I/O in order to perform the functions that you want, and it will require a lot of variables which won’t leave much room for anything else. If this is all you are doing then it is workable. There is probably a better way to do this, (I am still new) but here is one way to accomplish your needs.
·
Use a real time clock. Buy and install an RTC
·
‘ Declare variables.
T1
T2
T3
T4
T5
T6
Declare I/O
6 inputs
6 outputs
·
·
Main:
·
Switch 1:
If input 1 is not active THEN Switch2
Else read and store the RTC to switch 1s timer to variable T1····‘(This portion is skipped if the·associated input is not active)································
Activate associated output····························································· ‘(This portion is skipped if the·associated input is not active)
GOSUB subroutine Light1······························································· ‘(This portion is skipped if the·associated input is not active)
·
Switch 2:
If input 2 is not active THEN Switch3
Else read and store the RTC to switch 2s timer variable T2······· ‘(This portion is skipped if the·associated input is not active)·································
Activate associated output······························································‘(This portion is skipped if the·associated input is not active)
GOSUB subroutine Light2································································‘(This portion is skipped if the·associated input is not active)
·
Switch 3:
If input 3 is not active THEN Switch4
Else read and store the RTC to switch 3s timer variable T3········ ‘(This portion is skipped if the·associated input is not active)································
Activate associated output····························································· ‘(This portion is skipped if the·associated input is not active)
GOSUB subroutine Light3······························································· ‘(This portion is skipped if the·associated input is not active)
·
Switch 4:
If input 4 is not active THEN Switch5
Else read and store the RTC to switch 4s timer variable T4·········‘(This portion is skipped if the·associated input is not active)································
Activate associated output····························································· ‘(This portion is skipped if the·associated input is not active)
GOSUB subroutine Light4······························································· ‘(This portion is skipped if the·associated input is not active)
·
Switch 5:
If input 5 is not active THEN Switch6
Else read and store the RTC to switch 5s timer variable T5·········‘(This portion is skipped if the·associated input is not active)································
Activate associated output······························································ ‘(This portion is skipped if the·associated input is not active)
GOSUB subroutine Light5································································ ‘(This portion is skipped if the·associated input is not active)
·
Switch 6:
If input 6 is not active THEN Main
Else read and store the RTC to switch 6s timer variable T6··········‘(This portion is skipped if the·associated input is not active)·······························
Activate associated output······························································· ‘(This portion is skipped if the·associated input is not active)
GOSUB subroutine Light1································································· ‘(This portion is skipped if the·associated input is not active)
·
GOTO Main
·
Light1:
IF T1 + (desired on time delay) <= current RTC reading THEN de-activate associated output ·
Return
·
Light2:
IF T2 + (desired on time delay) <= current RTC reading THEN de-activate associated output ·
Return
·
Light3:
IF T3 + (desired on time delay) <= current RTC reading THEN de-activate associated output ·
Return
·
Light4:
IF T4 + (desired on time delay) <= current RTC reading THEN de-activate associated output ·
Return
·
Light5:
IF T5 + (desired on time delay) <= current RTC reading THEN de-activate associated output ·
Return
·
Light6:
IF T6 + (desired on time delay) <= current RTC reading THEN de-activate associated output ·
Return
·
Note that successive inputs prior to the “timer” expiring will re-initiate the timer.
Using this method will allow the inputs to be independent of each other.
Look at the RTC documentation for the proper method of reading the RTC and size requirements for the variable.

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(Frequently heard from other's)

Tommy, I know it wasn't designed to·x, but can you make it·do x·anyway?

·

Mike Green

The example I gave checks all 6 inputs (if you set maxInp to 6), determines the state of the outputs and keeps track of how much longer the outputs need to stay on once activated. The granularity, set in the example to 100ms, is adjustable. The actual time varies somewhat since Tommy is right in that the Stamp is not multitasking and isn't superfast. The time to do all the checking isn't included in the 100ms (which is a PAUSE where the Stamp doesn't do anything else). For most applications, a granularity for checking inputs on the order of once every 100ms or 50ms or 25ms is very reasonable.

SY

Mike, Tommy, thanks for the code.
I have been attempting to program Mike's code but its seems to get stuck on the first for..loop rather than go through the rest of the commands. I'm a·beginner programmer in basic so I keep getting errors such as "expects ":" or end of line" when·I keep the "i" after the NEXT. According to the manual·NEXT incerments my value and returns to the top of the loop, which explains why it gets stuck on the first loop. How can I continue to excute the code rather than go back to the top? the first thing that comes to mind is a·different·sub,·am·I right?
Also tried using count like the example - count var byte[noparse][[/noparse]maxInp] - but got errors as well.

I'm using the BS2 (if it makes a difference in the code).

Hope you can help.
Thanks.
SY

Paul Sr.

SY said...
Mike, Tommy, thanks for the code.
I have been attempting to program Mike's code but its seems to get stuck on the first for..loop rather than go through the rest of the commands. I'm a beginner programmer in basic so I keep getting errors such as "expects ":" or end of line" when I keep the "i" after the NEXT. According to the manual NEXT incerments my value and returns to the top of the loop, which explains why it gets stuck on the first loop. How can I continue to excute the code rather than go back to the top? the first thing that comes to mind is a different sub, am I right?

Also tried using count like the example - count var byte[noparse][[/noparse]maxInp] - but got errors as well.



I'm using the BS2 (if it makes a difference in the code).



Hope you can help.

Thanks.

SY

Mike is in 'Propellerland" - and doing some amazing things, I might add! No negative implication at all - it's all good!

Here is the code in "STAMP PBasic" - it should help you get going

' {$STAMP BS2}
' {$PBASIC 2.5}

maxInp    CON 2

CNT       VAR Byte(maxInp)  ' or whatever you need
i         VAR Byte
inPins    PIN 0
outPins   PIN 2

          FOR i = 0 TO maxInp-1
             INPUT i+inPins    ' initialize the inputs
             LOW i+outPins    ' initialize the outputs
             CNT(i) = 0      ' initialize the counts
          NEXT
theLoop:
          FOR i = 0 TO maxInp-1
             IF inPins(i) = 0 THEN skipPin
             CNT(i) = 50    ' if on, set count to max
skipPin:
          NEXT
          FOR i = 0 TO maxInp-1
             IF CNT(i) > 0 THEN makeOn
             LOW i+outPins    ' if count zero, turn off
             GOTO doNext
makeOn:
             HIGH i+outPins  ' if count > 0, turn on
             CNT(i) = CNT(i) - 1  ' and count down
doNext:
          NEXT
          PAUSE 100        ' this give approx 5 seconds on
          GOTO theLoop    ' do it all again

Post Edited (Paul Sr.) : 11/17/2006 5:37:55 PM GMT

SY

Thanks, I'll give it a try.
Sy

Tracy Allen

Hi Sy, there are a lot of ways to do this. The following starts the light on when the input goes from 0 --> 1, and it ignores the continued 0 or 1 state. The other examples hold the output ON so long as the input stays in the =1 state, plus 5 seconds. It depends on what you want it to do! This uses a trick with the Stamp operators ^ and & to detect a change in state of all 6 pins at once, and then decodes the effect on the counts and outputs. This assumes the inputs are connected to p0 to p5 and the outputs to p8 to p12.

old  VAR byte  ' old state of inputs
new VAR byte   ' new state of inputs
changeup  VAR byte   ' change in state of inputs 0->1
counter VAR byte(6)   ' array of 6 counters

old = inL   ' initialize
dirH = $ff   ' p8 to p15 are outputs

  DO
    new = inL   ' grab all six inputs
    changeup = new ^ old & new   ' detect changes
    old = new      ' update old
    FOR idx=0 to 5     ' effect on counters and outputs
      IF changeup.bit0(idx) THEN counter(idx)=50    ' index into bits of changeup
      IF counter(idx) THEN counter(idx) = counter(idx)-1   ' decrement if needed
      out8(idx) = counter(idx) MAX 1   ' set output if counter is active, note indexing into output bits
    NEXT
    pause 93   ' 93 milliseconds pause + 7 milliseconds for code (guesstimate)
  LOOP

There are ways to make the time for the code more exactly predictable, and ways using external clock to sychronize to clock time.

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Tracy Allen
www.emesystems.com

SY

Thanks everyone, you have been very helpful.
Its working!
Very grateful.
Sharon (SY).