The easiest and cheapest method is to blow the car's horn and wait a few seconds before opening the garage door.

The next easiest and cheapest option would be to use a wireless door bell and put the button in your car. It will only cost $10. But, it will require the driver to press the door bell first, wait for the desired time, and then press the garage door opener. Lots of opportunity for human error and not automated.

The over-engineered home automation method could utilize a LiftMaster Universal Garage Door receiver to receive the car's garage door opener button press.

But, instead of feeding the receiver's output to the garage door, you would feed it to a smart sensor, like a Z-Wave Door/window sensor to notify the home automation controller of the event.

The home automation controller can then run a scene that sounds the alarm in the garage, waits for a period of time, and then sends a garage door open command on a different channel, like a Z-Wave dry contact relay, or a ratgdo.

For the purpose of "emergency" access, in case the home automation system has failed, I'd also associate the second or third button on the garage door remote directly to the garage door. You won't have the alarm but you'll be able to open the door.

Many out there. Cordless doorbell, leave the doorbell button in the car. Simple.

Wireless Doorbell, Waterproof Door Bell Battery Operated at 1,300 ft with 2 Plug in Receivers Kit 1 Chime transmitter Remote Button, 55 Chimes 5 Volume with LED, Loud Enough for Home Classroom, Black

many garage door openers will flash the interior light whenever the door is ready to open.

If you need this to be audible (for the blind?) then there has to be a light socket screw in that a noise maker could be used. I have seen light socket to plug adapters. Then plug to noise maker.

MyIQ works with IFTTT right? So just need to find a buzzer / bell / smart switch & plug in buzzer that also works. Then hook it all up with ifttt

If you have a Genie garage door opener, and the "Aladdin Connect" app connected, it does exactly what you describe if you open the door via the app. Basically you press the button in the app, then the garage door starts beeping and flashing the lights, and then what seems like a few seconds later the door will start opening.

What is the model of your garage door opener?

The easiest solution is to use a relay. With the Zen17 I can press a button and open the garage and sound a siren at the same time.

Www.miltonsbells.com - old fashioned gas station bell alert

Buy any remote controlled outlet and plug any 120v noise maker into it.

If you have a z-wave hub, then there are z-wave key fobs you could use to trigger a routine to flash lights, start a chime, or any other smart device.

You could drive up to the garage and honk your horn before activating the EGDO.

yes this can (extremely) easily be done with home assistant. you just need a smart garage door opener and a google nest mini in your garage (for instance0

If you have a way to use zwave devices, I have the GoControl GD00Z-4 which flashes a light and beeps for 3 seconds before opening or closing the garage door. Only catch is it only does the alert/delay if triggered over zwave, so pushing a normal rf or wired button wouldn't make it go off.

It's actually the only thing I don't like about it because it cannot be disabled.

Does it need to be a button you press? If so, the app IFTTT can provide you a button on your phone screen that you can to send a request to an Alexa type device in the garage to do whatever.

But perhaps that is not the best approach. Have you considered a motion detector in front of the garage doing the same? If you don't have traffic in front of the garage, this might be a better option.