I just finished re-doing my garage door. I moved from MYQ to local controlled garage door like many of us here. I am pretty happy with it. I used to have a couple ST Arrival sensor that I put in my car and use to automatically open the garage door when my cars arrived home. These has not been working well with MYQ. Yet, after the local controlled GD, this automation is very useful again.
Now, I have a different problem. We just got a new car about a year or so ago. The ST arrival sensor seems not available or is very hard to find one for sale in USA.
I could use Bluetooth beacon for presence. But, I am a little concern because Bluetooth beacon does not require authentication. Anyone can copy the beacon packets and reply it over to open the garage door.
I have been making my Zigbee Sensors on another projects. I thought I could make an arrival sensor out of it. I am also looking for opportunity to make some improvement.
First, I want to address probably the biggest issue with ST arrival sensor. It has a very weak battery. It is well documented that many of us modified these sensors with bigger external battery. I am going with a different route for mine. I will use a re-chargeable battery. The battery will be re-charged during the drive. It will have enough charge for typical daily driven car.
Second, I will use high powered Zigbee module. I am hopping to get better connection compared to the ST sensors. I am also planning to use a Zigbee module that can use external antenna.
Here are is what mine will look like in the hub.
Here are a few things that are unique to what I make.
We will know whether the car is running by looking at whether the sensor is charged. I can configure different timeout based whether the car is running or stopped. This will reduce the false positive/negative of the presence status. When the car is leaving on its own power, a more aggressive timeout can be used. This will allow the "not present" detection much faster. When the car is not running, much more relax timeout can be used to be more robust in a non ideal Zigbee mesh.
I added an vibration sensor and microwave radar sensor. They will show up as motion and shock attributes.
We will have temperature monitoring for the car. Improvement 2 and 3 are intended to help securing the car when it is present at the house.
BTW, the firmware will also be fully compatible with Hubitat built in Arrival sensor. But, you will not get the extra information.
Here is my prototype board. Again, it is very rough and for my testing only. Eventually, I will have a specialized board made for it. This should be plugged in to cigarette lighter with 5V dc converter.
I will have a few PCB boards made specifically for the arrival sensor. It is not easy to source parts these days. When I am ready, I am happy to share the sensor for those who are interested. If you have other idea that you like to have on the sensor, please feel free to let me know. If I can accommodate it, I will be happy to do so.