ZigBee Arrival Sensor For Car

Hello Everyone,

I make a DIY Arrival Sensor for all of us. This is inspired from using ST Arrival Sensor in our car. The ST sensor has been discontinued. This is one of the reason I have to make my own. In addition, I make them because there are some weakness using the original ST arrival sensor in our cars.

I apologized for a long information. I would like to have the first post for all of us to get the latest information about this sensor. The topic may get very large. I want to prevent us to read all the responses to get the full picture of the sensor. I hope you can get all the information from reading the original post only. If you are looking for quick information on what you can do with it, please feel free to skip and just watch 2 minutes video of what it can do.

While making my own Arrival Sensor, 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.

The arrival sensor uses high powered Zigbee module. I am hopping to get better connection compared to the ST sensors. It also 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.

  1. 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.

  2. I added an vibration sensor and optional microwave radar sensor. They will show up as motion and shock attributes. I have posted info with a video link that is kind of eye opening for me. I hope this sensor can also double up as a way to secure our car.

  3. 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.

The firmware will also be fully compatible with Hubitat built in Arrival sensor. But, you will not get the extra information.

Here is the latest version of my Arrival sensor.

Here are pictures with different type of antenna. I want us to have the flexibility to choose the type of antenna that fit us. I personally choose based on convenience. My preference is the short antenna. I compensate with installing outdoor Zigbee repeater.

5.2 cm antenna

11 cm antenna.

19 cm antenna

Here are some casing example with a 3d printed case and off the shelve aluminum case. The 3d printed case is the only suitable case if you plan to use motion radar detector.

Here is a picture with radar motion sensor plugged in.

DTH: Driver and Installation notes

Factory Reset: Factory reset procedure.

I make a small quantity of the sensor in this batch for all of us who want it. The cost of the Arrival Sensor module is $29 +$5 shipping to any US address. If you are outside USA, I can find out the cost for shipping to your country. You will have to be responsible for the custom and duty. I can combine up to 4 sensor in one shipping easily. Please PM me if you are interested in the Arrival sensor. In order to fully assembled you will need the following parts.

  1. RP-SMA 2.4 GHz 50ohm antenna. You can find this type of antenna from old/unused WIFI routers. I can also supply the antenna pictured above. The cost of the antenna is $5 each.
  2. Optionally, you may want to install the radar motion sensor. I have some available. The cost is $5.
  3. You will need a JST PH 2.0 LIPO 3.7V battery with capacity around 300 mAH. Here is an example. Please note, I linked battery like this in the past. After a while, they have tendency to get out of stock. Please use this link just as an example. There are abundance of the battery.
  4. I use my sensor with case. I have a 3D printed case here. You can also purchase the aluminum case here. The aluminum case also has tendency to run out of stock. You just have to search it on aliexpress. The color is pink with size 23x44x60mm.

At the moment, to purchase the module, please PM me.

In some case, the sensor may not fully join your Zigbee network. Typically, you only see partial attribute 4 out of 5. Another way to tell you have this issue, shake the sensor and observe the shock attribute. It should change to detected. If you have this issue, here is my recommendation.


I want several if the R&D is not to expensive.

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Hello Iman,

I too am interested; for now, I'm using a SmartThings arrival sensor powered by a couple AA batteries.

Will it be possible for you to design a case for this product?


@tmcdonald, I will get some idea for the cost in the next couple of weeks. Yes, we will be looking for parts that would be reasonable.

@aaiyar, Thanks for the feedback. I will try to design the PCB to be case friendly. I do want to have a case for it. But, it almost likely would not be a custom case. We may have to live with pre-made box. What this mean is that, it won't be perfect (or perhaps look nice).


Have a look at the cases for the Raspberry Pi: Raspberry Pi Cases | The Pi Hut

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Amazing as always @iharyadi please let us know when you have something available.

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I just got these. Removed the space so.it.only has two batteries and soldeed the sensors.inside and velcroed to back deck.

Thanks @UKMedia for the cases ideas. I will look at them and see if I can match one with the PCB that I am making.

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Love this idea! Been playing with beam sensors to check for garage occupancy, but I’d prefer true car presence. And monitoring whether car is running is a great touch!

I’m not sure what you mean by this. Will the device work to report when the car is and isn’t present? When I’ve played with xbee’s in the past, the trick was always how fast the hub would rediscover the car presence sensor and report it as present. Needs to be pretty quick to trigger a garage door opener.

One related use-case I’ve not found a way to solve: putting an open/close sensor on the car door to trigger garage door to open just prior to leaving the house.

Nice idea!

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Yes, it will detect the car presence. Using the Hubitat built-in driver will only show presence. You will not be able to know whether the car is powered.

This is really cool. I would do this only when you have the car inside a garage. A couple of my car is actually is parked on my drive way. I would not want to have the garage door opened when I open my car door. Currently, my sensor is not precise enough to tell whether my car is inside my garage. I suppose we can looked at UWB sensors. I heard that UWB sensor can give centimeter precisions of your position. With this, you can tell whether the car is in a garage or outside the garage. But, the UWB is still costly.

BTW, my current microwave radar worked like a contact sensor. My car looked like a faraday cage. The microwave sensor does not detect any human outside the car when you have closed windows and doors. But, as soon as I open my door, it will detect me. It acts just like a contact sensor. I am ordering a different microwave sensor as we speak to learn about the different type of these type of sensors. My initial goal is actually to create 1 to 2 feet shield around the car. As people approach the car, I would be able to detect it.

I did something similar using a Xbee3 pro and programed the micro python code for 1 second transmitting. Just plug it into the cars usb outlet. When the car starts it powers on the Xbee3.
Then create a rule that automatically opens the garage door on arrival.
Works great for opening the garage when coming home as well.
Add extra range if you put a second Xbee3 pro setup as a router inside the garage.

Only issue is if parking in the driveway and you start the car it will open the garage door.

For just detecting if the car is parked at home I use a second old smartthings arrival sensor with the battery mod in a case but I also added a rechargeable circuit (I took from an old Xbox controller) with usb cable and rechargeable batteries to plug into another usb car outlet to charge the rechargeable batteries when driving.


I read briefly about using Xbee3 pro & the python. I decided not to go this route. I was not sure whether you would need to add battery. I am also not quite sure whether it would run as Sleepy End device or Repeater.

Since I am going DIY anyway, I thought that I would make my own. Here is just an idea of early PCB design for what I am thinking. I may want to resize the board to fit a pre-made box once I found one. The USB and SMA connector may also be gone if a suitable box is found.

you can program the Xbee3 pro as an end device or a router. For presence I set to end device and 1 second transmitting and they work great.

How much transmitting power is you DIY device transmitting or what is the range?
Xbee3 pro is Transmit power +19dBM approx * 300ft (indoor) to 2mile (outdoor) range.

Would be great if you could add a rechargeable circuit to use rechargeable batteries and be able to plug into a usb and recharge them while driving.
Likely a lot of demand since the smartthings arrival sensor are no longer made.

PS still running your original Homemade Temperature, Humidity, Pressure and Light sensor
works great!

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It is good to know.

Yes, it is pretty similar power +20dBM ish. I am going to use the module with external antenna this time around. It seems our car block 2.4Ghz signal really good. It is not just our house.

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BTW, I would like to confirm that It has recharge-able battery support. Even the prototype has it already using the Environment Sensors boards.

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A rechargeable circuit for rechargeable batteries I would definitely buy a few.
One thing the smartthings arrival sensor was missing.

The rechargeable circuit from the Xbox controller works great but I only had one old dead controller.
I tried some rechargeable circuit boards from china but they didn't work and just never got back to trying to source a working circuit.

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Understand, but will you release a custom driver that includes presence and on/off?

Yes definitely on when the car is inside the garage. I’m not sure, but Will the faraday concept work for my use case because I’m trying to get the garage door to open when I’m getting into the car to depart, rather than exit the car after arrival.

Also, you can solve for car presence in the garage by using cheap NO/NC photoelectric beams. Cheap and easy. Happy to share more of there’s interest.

The first version of PCB has arrived. Here are some pictures.

I get a couple off the shelf aluminum case and build the PCB to fit inside the box. The middle board is how the PCB looked like assembled.

Here is one way to cut the box panel. In this case, the USB and SMA connector is mounted on the PCB. I had difficulties to cut the panel. It is not that easy to cleanly cut aluminum. The module that stick out is the Microwave radar.

Here is another way to cut the aluminum panel with one hole on each side of the panel. I do not mount the USB and SMA connector on the board. I could just route and solder USB cable and SMA connector on the side panel.

I took a picture next to C4 hub to get some idea the size of the module.

I will assemble the rest of PCB. I will update everyone here what I will have to share for the community.


Looks great perfect for vehicles!

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