Humidity value freezing

  • I use a humidity sensor (DHT-22) to monitor the RH in a room and switch on a pond fogger and fan to keep the RH between 50% and 60%.

    Currently everything runs off AC power, I haven't gotten to putting these guys on batteries yet.

    Also currently this is the only sensor connected.

    When the sensor detects that the RH falls below 50% vera activates a z wave smart switch that has a box fan and ultrasonic pond fogger plugged into it. The humidity climbs quickly (a few minutes at most) back up to 60% at which point the vera turns off the switch and the RH slowly falls.

    This worked well for probably two months without a hitch. Then all of a sudden (without making changes to vera or the MySensor setup, or placement of the gateway or sensor) the RH value will stop updating. It usually happens within a few hours (i've not been able to figure out what may be triggering it to freeze) when it happens it seems the only way to get things working again is to power off the gateway and restart. Once it comes back online in a few minutes the values begin updating again and operation returns to normal.

    I've resulted to restarting the gateway in this way a few times a day, but obviously that isn't a long term solution.

    The setup controls the RH for a reptile room, so it is important that the RH not get too far off the 50-60% values. What happeend a few times is since the values don't update the switch never comes on and the RH falls to the RH of the rest of the house for long periods of time. Or worse (this has happened twice) the switch never reads the high value and never turns off, pumping moisture into the air and I find puddles on the floor.

    I'm not even sure the best way to approach fixing this, so any help is greatly appreciated.

  • Contest Winner

    how frequently are you reading the sensor? you may be applying a voltage too long or too frequently?

  • Admin

    A wild guess is that gateway radio ends up in a weird state. Probably because of power-issue.
    If it is possible, try stabilizing the radio power by capacitor (see other discussions on forum) and perhaps some other powersource.

  • @BulldogLowell Is there a way to check that value? I do remember changing the update frequency of the sensor to something shorter, but still in the 2-3 second range i think. It sounds like you may be talking about something different than that.

    @hek I've got the capacitor installed now, hopefully that stabilizes it, I've also moved the gateway radio closer to the sensor by a few feet. Hopefully that fixes things.

    Thanks for all the help, I'm leaving town soon and am hoping to get this working before I head out.

  • Admin

    @Larry-Schwerzler said:

    I just hope no reptiles will get hurt 😉

  • @hek The capacitor addition seems to be helping. So far 9 hours and all the values are updating as they should YAY!

    I'll continue to monitor but i'm hopeful that this is the solution.

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