Interfacing MH-Z16 CO2 sensor with PBP?

[CuriousOne]

Thanks!

So since pulse duration is so long, instead of pulsin I can use something like
WHILE PIN=1 A=A+1 and then count number of A's ?

For the analog output, my particular sensor does not have it, I talked to manufacturer (I bought sensor directly from them), they said this is optional feature and had to be noted when ordering the sensor.

Arduino library for the sensor is available, I'll try to connect to it later and check that way.

[CuriousOne]

I just tried this, but it always returns 0...

puka:
IF PWIN=1 THEN
X=X+1
ELSE
LCDOUT $FE, $C0, DEC x, " "
PAUSE 100
x=0
ENDIF
GOTO PUKA

[HenrikOlsson]

More than one issue with that piece of code. For one, you're running at 64MHz so it's probably going to wrap around X variable quite quickly giving you weird results. I'd try something like this:

Th VAR WORD
Tl VAR WORD

PWIN VAR PORTB.0


Main:
    GOSUB Measure
    LCDOUT $FE, $01, "High: ",  DEC Th
    LCDOUT $FE, $C0, "Low: ",   DEC Tl
GOTO Main

Measure:
  Th = 0
  Tl = 0

  WHILE !PWIN : WEND	' Wait for rising edge

  WHILE PWIN			' Measure high pulse width
    Th = Th + 1
    PAUSEUS 999
  WEND

  WHILE !PWIN			' Measure low pulse width
    Tl = Tl + 1
    PAUSEUS 999
  WEND

RETURN

Once you have that working, displaying pulsewidth values matching what you see on the scope you can A) increase resolution (if needed) and/or B) calculate PPMs or percentage or whatever you want to display. Small steps...

[CuriousOne]

Thanks a lot!
Will check it tomorrow.

[CuriousOne]

Just tried this code, it works fine, "High" displays readings consistent with actual CO2 concentrations, LOW displays some fixed numbers which only slightly change.