Your channel has one of the best audiences I have ever seen. So many comments are helpful and give new insights. Also, taking your time to reply to almost every comment is just wonderful. I am not even working with electronic, but I can feel this is a magical place.

Video link for those interested - kzfaq.info/get/bejne/mqeqe7uhtZmqk30.html

Thank you, Peter!

The LD2410 is also supported in ESPHome that exposes it's sensing data to Home Assistant.

@@ethzero is that the Bluetooth version or via serial? I have without Bluetooth, and used serial to configure. In use with only the high/low signal for detected or not. But can be used in so many ways :-)

I think LD2410 needs 5V

@@saninnsalas it uses 5V Power Supply, but have 3.3V logic. I think it has its own 3.3V reg onboard for stability.

You are right. I covered the LD2410 in a later video.

I do not know, but our home is quite old and in Switzerland, they only recently started with this metallized glass.

:D Spiders are the best!

I understand your frustration when troubleshooting this issue. Faulty Dupont wires and cheap breadboards have almost made me crazy when building and testing new projects. Based on your experience can you recommend a good radar sensor? I need a couple of them to detect birds and trigger an ESP32-Cam module.

@@oladunk9986 The versions I was using were pretty cheap and I believe the same as the XYC-WB-G1 as the switching time was the same, although you probably want a five second or less on time if you just want triggering, it will give you more captures per minute. In that case the RCWL-0516 or HW-MS03 would be good candidates, although the more expensive HFS-DC06 is likely to be more stable with less false triggers. The best part in detection with these is the daytime performance matches night, unlike PIR, and the sensor can be sealed from the elements. The downside is they can be triggered by wet foliage in the wind, insects and sometimes just nothing (may actually be flying insects...), but they are cheap. Good luck.

Wonderful story; and although spiders are not classified as bugs, this is definitely....real debugging.

Awesome engineering have done. Simply wow!

You are right. As said, this is an old video and in the meantime, a few viewers suggested this. It is good because if it is a receiver, it is prolly more legal ;-) BTW: I once made a video about a tube Regen receiver…

Thank you for your kind words!

These sensors work very different to the „real“ radars you describe. These sensors only have one transistor which has to do all functions…

These devices are not real radars, they are regenerative receivers (mentioned in other comments). Do there is no worry about interferences.

I don't anything this size will emit anything near the power required to drown out such a high powered radar.

Rain radars (actually called weather radars) operate in the 5GHz wifi band. Wifi routers that operate in the range 5250-5350 and 5470-5725 MHz must use a mechanism called DFS or dynamic frequency selection to change channel if they detect a weather radar. DFS is not required in the 5150-5250 MHz band and in the 5725-5875 MHz band. Some manufacturers allows the user to disable DFS, which is is illegal and causes weather radar interference. Problems usually occur with WIFI access points installed outside, on top of a hill, or in a tall buildings.

@@atmel9077 The frequency of the rain radars depends on the intended range, not all operate around 5 GHz. Higher frequencies have a shorter range, but better sensitivity to smaller droplets. For vertical profiling, around 90-100 GHz is used, short range, but much better sensitivity for smaller droplets. But indeed, there are several (proposed) license-free channels that are of concern for observations used for weather, including passive microwave for water vapour measurements. Those can't be put on a different frequency to avoid interference.

​@@MrGeekGamer The transmitter of the rain radar is not the issue. The reflected signal from a collection of raindrops is small, and drops off quickly with distance. (1/r² for the transmitted beam, another 1/r² for the reflected signal, with a strong dependence of the reflected signal on the droplet size). Even low power transmitters can easily overwhelm the reflected signal, especially for small droplets.

@jacquesmertens3369 Switzerland is very versatile: Some Swiss chocolates or candies might be even cheaper 🙂

Indeed, Switzerland is expensive. But I experienced that other "holiday" countries in Europe catch up quickly :-(

Indeed, for me, it is still unbelievable how sensitive they are!

You are right, they are regenerative receivers!

The solar videos were not too successful. So I was not sure if I wanted to du an update. But maybe I will do it now…

I will! Thank you.

Maybe you have also a look at the LD2410 (I also made a video about them)

I will. Thanks!

I agree.

Thank you!

Thank you!

Thank you!

They should be widely available.

I agree that these sensors are. Good choice. I already made a video about them…

Thank you for sharing your experience!

Thank you for sharing your experience!

I will try ;-)

Thank you!

Gracias!

I do Not plan intros for the remaining videos, but maybe add the original number in the description.

Thank you! Was my pleasure, too.

Thanks for sharing your experience!

Maybe you now find a project for them ;-)

Thanks, you too!

@@AndreasSpiess Thanks!

Thank you for sharing this enhancement!

Thanks for the info!

Thank you!

I will. Thank you!

Cool. Thank you for sharing your trick!

I once made a video on how to hack IR devices. But it was not as easy as you describe ;-)

Thank you! You too!

You are right!

As many others stated, they are not real radars. I had real radars ( they are more complex) on the channel. But their range is not much longer.

Just saw your pinned post on regenerative receivers.

Indeed, when I made the video, it was not clear. Only after reading some comments, it became clear that these are "only" receivers...

Thank you for sharing your learnings. Interesting!

@@AndreasSpiess the module I used appeared to have a earth plane, but was still sensitive in the reverse direction. If the frequency used is 24GHz, then one might expect an effective stand off distance from the carrier board earth plane to be 1/4 of a wavelength, approximately 0.3115 cm, as this would produce a voltage node at the surface of the earth plane. The next standing wave would be at 3/4 of a wavelength. This is the standoff distance that can be achieved using the roll pin plug and socket as the interface. In practice, I doubt if the frequency is that well controlled, and the precision of the standoff distance is not that accurate. My test equipment does not reach 24GHz,, I resorted to looking for changes in the supply current, reasoning that this might show loading of the Tx. There were small changes, but nothing conclusive. The range did not appear to be adversely affected by the earth plane of the carrier board, but it did greatly increase the directionality of the beam.

Another video on radars is planned. But I still did not find a cheap radar capable of detecting on a long-range :-(

:-)

You are welcome!

@@AndreasSpiess curious what happens when i mount one sensor on each table of ma office to measure how many seats are available. At the 5-7m range and 4x 160cm tables next to next do they disturb each other? Or can i focus the beam by using a bowl lined with Aluminium foil ?

@@olafschermann1592I do not know, you have to try.

I agree

I am also puzzled by how sensitive these cheap devices are!

I pinned a comment on how they work. They are simple receivers like back in the old days...

Thank you for the info!

Thank you! You to.

Keep in mind: They only have one transistor. So such functions are not possible.

I will! Thanks.

Mach ich ;-)

Vielen Dank! Der Urlaub wird hauptsächlich „ums Haus“ stattfinden…

Thank you! 😃

And we have 36 degrees outside ;-)

@@AndreasSpiess Stop bragging 😒, Andreas. 36 is cold for our summers.

Indeed, these devices are regenerative receivers, not radars.

I do not know if they have such a feature in their plans...

@guatagel2454 My experience with these cheap radar sensors: They work best with an own power supply using a linear voltage regulator + caps. Connecting to the supply of a Wemos did not work for me.

I also had false positives. I found adding a capacitor to the power rails and a resistor on the Vcc line to create a simple rc filter fixed it

@@fluteplayerify congrats! I my specific case RC did not help, But in both cases an improvement of the supply path was the key.

There are some posts on the internet about this issue and some suggestions to resolve it. Another possibility could be to use a more modern LD2410 sensor (video #439)

:-) 73 de HB9BLA

Read the comment about the spider ;-)

Thank you for sharing your experience. This sensor seems to be very good. However, it is a bit pricey if you do not need its particular features...

I will! Thank you.

I made a video about the ld2410

Please do! They seem to work on different frequencies.

No. Maybe you have a look at the video about the LD2410?

Back in the day, most electronic devices were quite simple designs, I think. They just did not have the capabilities for better equipment. However, they worked!

Agree, or at least look at the demodulated IF on an Oscilloscope. Do you know some good and easy to use software to analyze signals ?

Getting speed information is trivial, just do an FFT to extract the beat frequency. Things like distance measurement is a different story and it's better to use radar sensors dedicated to that.

There is no IF. These seem to be „regenerative“ receivers where the only transistor acts as a transmitter, too.

The ones shown here vary a lot in frequency. They can be classified as receivers an so are legal even if they transmit a bit.

@@AndreasSpiess Okay, understand. So the principle is at bit different than with dopper radar sensors like RSM-1650 for example..

@@EinzigfreierName It is completely different. They even cannot be named "radars". But I did not know that when I made the video...

Thanks for sharing! So the HFS-DC06 and the SK-600 are in the 5GHz Wi-Fi band!

Maybe. But our windows are quite old...

I do not know the laws around this topic :-(

I do not see why I should connect anything to the input if I connect power to the output. As you say, there should be a difference between the two pins. So the input will be cut off by the LDO.

Reinforced most probably will not work because of the metal.

Danke!

No. Cars have different sensors (more sophisicated)

These devices have no mixer, etc. because they only have one transistor. They are regenerative receivers. The IC have no receiving function, just threshold and timing.

@@AndreasSpiess Yeah, I understood it while watching other videos from you - this is a creative way to measure distances.

@@hankhulator5007 Actually, they cannot measure distance because their "sensitivity" heavily depends on the size of the detected object. They are only suitable for presence detection.

@@AndreasSpiess That's good enough, my project being to couple one of these with a PIR to ensure no false positive. I also have to investigate about such a device that uses one of the more expensive RADAR you presented, the one with 6 little squares - a guy (you ?) has made a device combining an ESP32, a RADAR and a PIR which distance of detection can be set remotely ( ahhh, I found my bookmark about this one back : kzfaq.info/get/bejne/oLyapcqCuL3QfH0.html )

From my understanding here is how it works: it's basically an oscillator which is an amplifier with its output going back at its input through a filter. If it is an inverting amplifier the filter gives a phase shift of 180° at the resonant frequency. The amplifier is saturated and operating in a non linear region (fully on or fully off). The reflected signal will self-mix with the oscillator and create a DC offset. If there is motion the phase of the reflected signal changes so the DC offset oscillates at a low frequency. The DC offset is amplified and bandpass filtered (say 1 to 10 Hz) and goes to a comparator which triggers the sensor. More in-depth explanation : because the amplifier is saturated, the collector is periodically shorted to the emitter, when there is a base current. The transmit/receive antenna is connected to the collector. When the peak of the reflected signal is in phase with the collector not being shorted, it will give a residual DC voltage, higher than when the peak of the reflected signal is in phase with the collector being shorted. The slowly varying DC voltage is processed by the IC chip, often a BISS0001 designed for passive IR sensors, as those output a similar low frequency signal.

:-)

That would be cool!

???

Thank you! 😃

I share the ESP32 internet using the Wi-Fi hotspot functionality of the smartphone. I do not think that doing it via Bluetooth is a good idea...

@@AndreasSpiess I do already have wifi working but for my application a bluetooth internet connection would be so much better for battery life and end user experience. thank you anyway

I will. Today, we had 36 degrees in Switzerland…

The IC is well known it contains nothing special (no RF function)

@@AndreasSpiess Perhaps one of the inputs will allow conclusions to be drawn about how it works. For sure PCB does not look like 24GHz 🙂It even does not look like 5.8GHz but I will check this using my SDR but that antenna length also indicates lower frequencies. Maybe a super fast transistor is able to generate harmonics. My guess is, this is just called "radar" but principle is something completely different. The human body has impact on resonance or may be even SWR.

@@greekstraycats You will see a signal in the GHz range in the air. As many comments suggest, these devices are regenerative receivers, and they emit a small signal via the antenna.

I agree. But these sensors are not made for that.

Indeed, I enjoy already beautiful weather ;-) Happy summer for you, too!

They are widely used for presence detectors.

@AndreasSpiess can you build one and show how to build it and maybe use it on an rc car or something like that? That would be funny 😁

@@sauliusjance6300 Usually, presence detectors are mounted in a fixed location to switch lights on or off ;-)

The PWB antennas are not directional (as the tests demonstrated), except for the one which has a groundplane/cover mounted behind it. You could make them directional by mounting them in front of a metallic groundplane or corner reflector. You could even mount them at the focal point of a paraboloidal reflector. Make sure the mounting is rigid; any relative motion of the sensor and structure will trigger it. You're essentially making this the feed for an antenna of your own; ideally you would determine the operating frequency and design the antenna for the pattern you want. But the analysis is fairly involved; if you're not too particular, you can get significant directivity from ad-hoc approaches.

There are other comments where people experimented with metal surfaces and were able to get different patterns.

It depends on the size of the object.

I included a link for this product (Bangood does not sell it anymore)

Where I live, this is available. "xcluma 5V-30V Delay Relay Timer Module Trigger Delay Switch Micro USB Power Adjustable Relay Module"

Generally, you need a microcontroller to get the behavior you want. Only if the sensor does exactly what you need, you can do without it.

@@AndreasSpiess I'm on solar 12v input. Can usb to 5v. This device puts out 3v so that's my issue. In not electronics educated, I generally watch utube and do understand. But I'm a novice. So some doorbells run of 3v. But probably more amps again. So all I'm trying to do is step up v and a. The 5seconds is ok, for an alarm. It's some 100m away from me, the setup. So audio alarm is good. And if there's continuous movement it will trigger repeatedly. So that's ok too. But ideally I want to trigger a 12v output. So I've seen there are 5v relay boards out there. Just wondered if you have the patience to demonstrate something along those lines. Many thanks.

@@earthlingthings Your questions are far too big for a KZfaq comment. Maybe you search for a device that runs on 10 volts and is capable of switching at least 12-volt loads. Or you start with simple things like a voltage regulator to convert 12V to 3.3V and so on and learn all the stuff needed to build such a device.

Vielen Dank. Heute war es auch 36 Grad hier…

I agree. However, ours is pretty old.

I do not know. The car contains a lot of metal and maybe it interacts. You have to try.

@@AndreasSpiess Mate, you've the hardware there, how about giving it a crack and report the findings? If you find an easy/cheap option to do so, you might have a best seller video. I'm sure it find an wider interest than more than just our regular electronics cohort.

I agree with your statements. These sensors can be triggered by close enough WiFi antennas.

I do not think so.

Same transistor used for transmitter and receiver is called regenerative receiver.The transmitter is disturbed by an external object or signal and create a difference which can be demodulated. Very old way of building radios for pagers and remote control for boats and airplanes. Also built with tubes before WW2.

Oladunk is right. These are regenerative receivers. They are no more used these days. The chip does only the threshold and the timing.

I agree with your statement about Glas. Our windows are simple and old… As many others stated, these devices are regenerative receivers, not real radars. But they have a similar effect for a ver low price.

Maybe. But also read my pinned comment.