Zigbee mmWave Presence Sensor

Hi Everyone,

I have been watching the development of mmWave modules. I am interested on it because its capability to detect stationary human presence.

Recently, I notice that the availability of such modules are becoming more common. So I thought I would make a Zigbee solution that would take one of the off the shelve mmWave module and make it available as occupancy sensor for our hub.

Here is my first board for it. It was designed for DFRobot sen0395 module. It is out of stock everywhere. I am getting a similar module from Aliexpress as we speak. I do not have one on my hand yet. I am testing it with my 5.8GHz radar based motion sensor. Here is the first board.

It is AC powered.

I designed it to be installed in electrical box. I will eventually install it next to my wall switch in the room that I like to monitor.

The Zigbee firmware is being tested. I am able to pair it with our hub

I am using nrf52840 for the Zigbee module. This is reasonably newer MCU which support thread(matter). In the future, if I happen to run matter in my house, I want to make sure the sensor is capable to support matter.

I am still very early in this project. I am in the process of getting mmWave modules to evaluate. If everything goes well, I may have boards that I can share with the community.

Thanks
Iman

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What kind of price do you think this type of devices is going to run? I think it's Aqara that is building one for use in China only.

The mmWave module is typically around $30+ in USA. They are still very expensive. But, I started to see one module that is in $10ish in AliExpress.

I am in the process of evaluating them. It is still difficult to source these modules in USA. But, if you do not mind getting them from China, they are widely available.

At the moment, I want to make sure that we build/design the Zigbee side of this.

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Very nice, Iman!

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Looking forward to seeing where this goes!

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Sounds very ambitious, good luck!

Is this sensor FCC approved for use in the US? That is likely a good reason why they are not readily available.

https://www.fcc.gov/engineering-technology/laboratory-division/general/equipment-authorization

Before you can use such a device, you would need to determine if it needs FCC approval or if the MM Wave radar device has been approved. If not, then it would need to be approved if required by FCC rules. Before you could distribute it, you definitely would need to determine if approval is needed, and if so, that it is done.

Are these modules considered safe in long term use? For example I wanted to put an FP1 sensor near my baby's crib to detect presence but I'm not sure if constant mmwave radiation exposure in that setting is harmful in any way.

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First, the modules that I am watching are not FCC approved based on the brief web page offering. However, I do not think the issue with availability is due to FCC approval. I have saw a lot of posting from IOT enthusiast purchasing and use them. I think it is just the demand is so much higher than the supply.

At the moment, I am trying to get some of the modules for my personal use. I would like to get some idea how well they work to improve on PIR like motion sensor. The mmWave sensing sensor will eventually need some sort of pipe to deliver the information to our HA system. I am investing my effort to build this Zigbee pipeline (or perhaps matter in the future). I hope in very near future there will be more clarity in regard to mmWave regulation.

At this point, I do not think a lot of people knows about any side effect. From what I can understand about most of mmWave radar available today is that they transmit a low power wave. I am comfort able with 20db continuous exposure to Zigbee wave at home today. I am exposed to 30db wifi wave all the time. I believe that the mmWave modules sold today is transmitting much less than Zigbee and WIFI. This is not an apple to apple comparison. But, I can only make my educated guess based on how much potential energy those type of device transmit.

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@alexcapone

FWIW, there are medical devices under test for remote monitoring of patient vital signs that use mmWave radar. Therefore, like @iharyadi, I am not particularly concerned about exposure to mmWave radar.

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https://www.fcc.gov/millimeter-wave-708090-ghz-service

Again, I say that any MM Wave device would need FCC approval before it can be legally sold/distributed in the US. That applies to any device that emits RF energy. As a licensed amateur radio operator, I am perhaps a bit more aware of the FCC requirements. The FCC has this to say:

The FCC regulates radio frequency (RF) devices contained in electronic-electrical products that are capable of emitting radio frequency energy by radiation, conduction, or other means. These products have the potential to cause interference to radio services operating in the radio frequency range of 9 kHz to 3000 GHz.

Almost all electronic-electrical products (devices) are capable of emitting radio frequency energy. Most, but not all, of these products must be tested to demonstrate compliance to the FCC rules for each type of electrical function that is contained in the product. As a general rule, products that, by design, contain circuitry that operates in the radio frequency spectrum need to demonstrate compliance using the applicable FCC equipment authorization procedure (i.e., Supplier's Declaration of Conformity (SDoC) or Certification) as specified in the FCC rules depending on the type of device. A product may contain one device or multiple devices with the possibility that one or both of the equipment authorization procedures apply. An RF device must be approved using the appropriate equipment authorization procedure before it can be marketed, imported, or used in the United States.

Just because IOT enthusiasts are purchasing and using these devices does not mean they are in compliance with FCC regulations.

@alexcapone You are right to be concerned. As @iharyadi mentioned, there isn’t enough long term studies of the effects of mmW on our bodies. While I’m interested in these, I would never use one at this early stage of their existence, and in an area of constant exposure. These are my personal opinions and feelings about them.

Babies and small children have soft, and unformed tissue. Personally, I would not expose them to such devices. This is my opinion, so it’s not up for debate. I’m just offering it. You are of course free to make your own choices.

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I don't have any disagreement with statement. But, I would not speculate about the FCC compliance of the modules that are available on the market today. One of the module that I am planning to use is DFRobot sen0395 when it become available. It is sold through Digikey, Mouser and DFRobot website.

In the past, I have personal experience where a maker does not marked their modules as FCC compliant but in fact they do have certificate of compliance on hand. I sense that @StephenH that you care about the compliance at the moment. I am sorry that I would not be able to give you information for a module that is sold and made by other vendor. Perhaps a questions to the retailer or the maker is in order for you @StephenH.

To share a bit hopeful news, there are similar technology which would detect stationary human presence. It looked like that it is a bit ahead in term of FCC approval. What I am doing here could be adopted to use NOVELDA UWB X4F103. It is a similar radar technology that can detect breathing human and other precision location capability.

I hope that I am ready to have something for us when either mmWave or NOVELDA (uwb) sensor is ready on the market. I am building a board for us who has pioneering spirit to evaluate mmWave and UWB technology. The radar technology, that solve stationary human detection, is too important to ignore.

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I'm not arguing with you on building the device. I hope that the module is approved, or will be soon.

There are probably already a lot of 5.8GHz motion radars that are already installed and in use in the US... just not 'smart', but simple relay dry contacts.

Like this one:
https://www.amazon.com/CONVENIENT-Microwave-Motion-Intelligent-home-use/dp/B08J8F3XHN/

Or this: https://www.amazon.com/J-LUMI-YCA2002-Microwave-Doppler-Detector/dp/B08B7RW4M1/ref=psdc_11040971_t2_B07HQC9KXK

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Very cool, also looking forward to seeing where this goes.

I could be missing something, but since we are talking about devices that will be mounted on a wall or ceiling, I don’t see much cause for alarm.

Perhaps a device that uses this frequency range, in close contact with the human body over a sufficiently long period of time, could act differently.

Of course, absence of evidence is not the same thing as evidence of absence. So everyone should indeed make decisions based on their own risk tolerance.

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I just read something a couple days ago comparing mmWave being used for non-contact imaging of infants v/s ultrasound. Wouldn't surprise me if in 10 years time, ultrasound imaging is augmented by mmWave (or vice-versa).

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I have 3 sen0395 in service in my house, and 2 seeeduino 60ghz ones.

They work well - with some caveats that pets will set it off even on lowest sensitivity setting. ceiling or rotating fans will too without very careful placement or shielding.

In theory one could get sophisticated with the seeeduino 60 gigahertz one and tune out items such as ceiling fans (via point cloud analysis, or via their angle of sight adjustments), but it takes a bit of work. Not sure the same flexibility exists on the DFrobots version.

I really don't care about fcc cert, and most certainly don't care about interfering with ham/short wave radio operators for my own reasons, so I'll stay out of that discussion.

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I'm very interested on how you've set up the 60 GHz ones. Because those are fine-tuned enough to be used to detect heart rate and breathing rate, and with this are already used to determine if someone is sleeping or not.

If someone of you guys could set one of those things up, it would give us so a great new way of automation. SLEEP! Guys, seriously, how cool would that be? Sleep as a trigger for your rules!

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Seeeduino makes 2 different ones - one can do heartbeat/breathing (sleep), one can't. I have the one that can't - the "fall detection" model.

Screenshot 2022-07-19 12.07.19 PM

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