How I Hacked My Video Doorbell to Scare Trick-or-Treers

Smart home technology isn't just for boring things like monitoring the humidity in your home or locking your front door at night. It can also be used for more fun things. I decided to see if I could hack my video doorbell to scare trick-or-treaters.

We have to leave our sweets unattended

Halloween is my son's favorite night of the year, even more than Christmas, because apparently a handful of candy is better than a bunch of expensive gifts. That is, every Halloween, after watching The nightmare before ChristmasThe whole family has to go trick-or-treating together.

This means no one is home in case trick-or-treaters show up at the door. My kids would never forgive me if we didn't leave candy for other trick-or-treaters, so we leave a bowl by the front door for anyone who comes by to help themselves.

I wanted to scare people so they would take their fair share

The problem with this method is that it is prone to abuse. In years past, people had far more than their fair share of the candy, so when other trick-or-treaters arrived, there was nothing left.

I wanted to come up with a fun way to scare trick-or-treaters when they arrive while also trying to get them to eat just a handful of candy. My first thought was to get really complex and try to use AI to analyze my video doorbell feed so it can detect exactly when someone takes candy out of the bowl. This idea was soon scrapped when I realized that the area where we placed the dish was too dark to see clearly in the doorbell signal at night.

Ultimately I decided on something simpler. I wanted the video doorbell to speak some creepy pre-recorded voice messages every time a person is detected by the doorbell.

Record creepy voice messages for my doorbell

I have a Reolink Video Doorbell Wi-Fi that I received as a replacement for my Ring doorbell, so I don't have to pay a subscription or rely on cloud services. One of the features of this doorbell is that you can record your own custom quick replies to play when someone rings the doorbell. With Home Assistant, it is possible to create an automation that plays one of these quick replies when a person is detected by the video doorbell.

Recording the scary messages is easy. In the Reolink app, tap the Settings icon and select Sounds. Select “Voice Message” and tap the plus sign (+) in the top right corner of the screen. Tap Start and record your message. Then tap “Finish” when finished.

Tap Sound Test to listen to the message again. If you're not happy with it, tap Re-Record. When you're happy with your recording, enter a memorable name at the bottom of the screen and tap Save.

Once you've recorded your messages, you'll need to restart Home Assistant for them to appear in the Reolink integration. In the end, my kids recorded several different quick answers. I decided I wanted to play them randomly so people didn't get the same answer every time.

Creating the Creepy Automation

The final step was to set the custom responses to play whenever a person was detected at the door. People detection on the Reolink is pretty solid, meaning replies should only play when there are people at the door, and not when any type of motion is detected.

Triggering the automation is quite easy as there is a binary sensor (binary_sensor.your-doorbell-name_person) that changes when a person is detected by the video doorbell. I can trigger the automation whenever this binary sensor is turned on.

Playing voice messages is also easy. The Reolink integration with Home Assistant includes an entity called Play Quick Reply Message, which, when combined with the name of the Quick Reply, plays the message through the video doorbell speaker.

The hard part was getting the doorbell to randomly play one of the multiple voice messages. This was complicated by the fact that there are three default voice messages that I had to make sure were not selected for playback. I used ChatGPT as inspiration and ended up with the following code that does exactly what I wanted:

alias: Spooky Doorbell

Description: “”

Trigger:

– Trigger: Condition

Entity ID:

– Binary_sensor.reolink_front_door_person

to: “up”

Conditions: []

Actions:

– Action: select.select_option

Metadata: {}

Data:

Option: >

{%set allowed= [‘Haunt’,’Watching’,’Peril’,’Ghosts’] %} {{

(state_attr('select.reolink_front_door_play_quick_reply_message','options')

| select('in', allowed) | List | random) or allowed|first }}

Goal:

Entity_ID: select.reolink_front_door_play_quick_reply_message

Mode: Single

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This will randomly select a message from the list of allowed messages so that the default messages are not included. If you do the same, you will need to replace “reolink_front_door” with the name of your Reolink doorbell and “Haunt”, “Watching”, “Peril” and “Ghosts” with the names of the voice messages you have saved in the Reolink app.

A simple but effective Halloween hack

After I created my automation, I tested it and was pleased to find that it worked exactly the way I wanted. Whenever a person is detected by the video doorbell, one of the pre-recorded spooky voice messages will play, warning trick-or-treaters of the consequences if they consume more than their fair share of candy.

The randomization works exactly how I wanted it to. Each time a person is detected, the message played is randomized, so it won't always be the same message when someone comes to the door. It's a simple idea but it works really well; The sudden scary news is enough to scare the trick-or-treaters a little, and hopefully embarrass them enough to leave candy for everyone else.

The best part is that everything happens on site. No video or voice messages from the doorbell are uploaded to the cloud. All processing and automation is done on my Home Assistant server.

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Most of my automations are convenient, but not very exciting. It was a lot of fun getting an automation to do something entertaining. I had a lot of fun setting it up and the kids really enjoyed recording the spooky messages. Now all that's left is for a few unsuspecting trick-or-treaters to show up.