OpenGarage Forums Hardware Questions Relay – High on boot?

This topic contains 4 replies, has 2 voices, and was last updated by  tekbar7522 5 months, 3 weeks ago.

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  • #1374

    tekbar7522
    Participant

    Hello,
    I have flashed a esp8266 with opengarage, hooked up the distance sensor and relay, and I noticed that when the power is connected, the relay turns on. When I reset the power (to simulate a power outage), it disconnects the relay. When the power comes back on, the relay turns back on. Shouldn’t it be the other way around where the power and the relay is switched off all the time, unless I push the button to open/close the garage?

    I tried changing the GPIO pin to different pins (and re-compiled the firmware) to see if its related to the board or pinout, and it was the same scenario.

    Is this the way that it is expected to work? I havent hooked it up to a garage door opener yet, and just testing before installing it in my garage. The way it looks like it will work if there is a power flicker, it will flip the relay off and then on, which would simulate a button press which would open the garage.

    #1375

    Ray
    Keymaster

    This depends on what kind of relay you have. Some relay modules are active low, so if the control signal is low, it activates the relay.

    #1381

    tekbar7522
    Participant

    Thanks for your quick reply. So the signal is actually low coming off the board during boot, right? In that case, I will order a relay that is active on high, and test again.

    What is the best way of testing with a multimeter if it is high or low?

    #1382

    Ray
    Keymaster

    Yes, OpenGarage uses active high logic, signal is low at resting state.

    #1383

    tekbar7522
    Participant

    Thank you Ray. I just tested it by hooking up a multimeter to the nodemcu, and it stays at 0v (even when I reboot it). The volts only go up when I switch the door open/closed.

    I will order a relay that activates on high. Thanks for your help.

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OpenGarage Forums Hardware Questions Relay – High on boot?