Sleeping Z-Uno and DHT sensors

[michapr]

Issue is not easy to describe...

Following steps:

-exlude Z-Uno (to be sure...)
-Upload this sketch without the delays in line 28,36
-Device will not go into sleep mode (LED is blinking)
-including the device in Z-Way -> ZWay show sleeping device. Changing wake-up, all seems to be ok, but device will never wakeup and change values. LED is still blinking

-exlude Z-Uno
-Upload this sketch with the delays in line 28,36
->LED will (in most cases) still blink - Z-Uno is not sleeping
-Make factory reset - upload same sketch with the delays in line 28,36 again
-> Z-Uno will go into sleep mode
-including the device in Z-Way, set wake-up - all seems to work fine, values will be changed after wake-up.

-edit sketch - as sample change delay from 2000 to 3000 seconds, upload sketch (rescue mode)
-> Z-uno will not go into sleep more
-> exclude, factory reset, upload - Z-Uno will go into sleep

If Z-uno will go into sleep mode, you can not upload changed sketch more (rescue mode of course) - Z-Uno will not go into sleep more, only after factory reset.

Strange issue, I hope you understand. It is reproducable.
ZUno2DHT22a.zip

First issue seems to be that DHT sensors are not ready. Changing any values in lib only didn't help.

Without DHT sensor lib (with fixed values) all is working as expected

Michael

[michapr]

Maybe found first issue in DHT lib:

in ZUNO_DHT.cpp:

void DHT::begin(void) {
// set up the pins!
pinMode(_pin, INPUT_PULLUP);
_lastreadtime = 0;
}

later:

if (!force && ((currenttime - _lastreadtime) < 2000)) {
return DHT_RESULT_PREVIOUS; // return last correct measurement
}

After wakeup the _lastreadtime will be 0 - so no value will be reported.
I think initial value should be 2000

void DHT::begin(void) {
// set up the pins!
pinMode(_pin, INPUT_PULLUP);
_lastreadtime = 2000;
}

Can you recheck it?

[PoltoS]

@p0lyg0n1 we should use NZ for such values.

[michapr]

@PoltoS I think in this case it is not needed - for sleeping the sleeping time > 2seconds, so this value can be ignored (if calling function once).
If not calling once or not sleeping - it will work, I think so. Only initial value for first call should be 2000, so that will be executed.

[michapr]

My solution is not full correct - because of currenttime will be some ms only... So could be better to check for (initial value) ( _lastreadtime !=0 && (currenttime - _lastreadtime) < 2000)) or something like that.
But there is something else wrong - even if it is working - Z-Uno will hang after some time (maybe hours) ...