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It "looked good" for me up to 100Hz after Nyquist in the spectrum but didn't pull any precise data. Just created a 50Hz tone using my speakers which showed up in the spectrum afterwards as expected as basic verification
Took some spectras from heat pumps, airplanes and a helicopter.
So the sensor isn't blind within this range.
Sadly you have to install the codecs from external sites.
This - at least for me - messes up the rolling release stuff at least one a month.
Honestly: don't know.
My experiments never had a dependency on linearity.
Theoretically wind can be Nulled with a 4-way water splitter that are placed in 90° angles (+ a connector at the bottom to the sensor). As long they are orthogonal the wind pressure coming from one side will cause a negative pressure on the opposite.
Only pressure waves coming into all holes at the same time will reach sensor.
Never tested it. Only a Gedankenexperiment as Einstein would say.
The Sensirion SDP600-25Pa speaks I2C and only has a handful of primitive commands. Add this and 3.3V and you are done.
I'm 99.5% sure if you throw Claude with a datasheet on it will Slop out working code for a ESP32 with ESP-IDF.
Not much circuits needed.
The SDP600-25Pa speaks I2C and only has a handful of commands.
Just read it out with a microcontroller you love (like ESP32) and send the samples to a host for analysis. The ESP32 has limited I2C time stretching capabilities limiting it in the highest resolution modes of the sensor - but often that's not a big factor.
To not overwhelm the poor processor and Wifi maybe better a bunch of frames (like 512 or more).
Yes. But they usually are not performing very good between 1-250Hz.
Sensirion is using a thermal flow-sensing principle method which is basically a heated plate that cools/heats up when air passes it - making it extremely sensitive in this range.
If these Shahed drones have a propeller they should have a brutal signature between 0-250Hz as they are moving a lot of air. And if the engine speed of the Shahed stays constant it will be even easier to detect it ("Angry lawnmower sound".. but that's only the high frequency part of it).
There are extremely sensitive differential pressure sensors (like SDP600-25Pa) available from Sensirion that aren't overly expensive.
Use one differential side and connect it to a kitchen funnel for directional listening the other one to a plastic bottle with a tiny hole in it. This way the sensor will "Null" out the environmental pressure (which the bottle follows very very slowly) from both inputs. It then only will pick up everything high frequency which is left over (and the bottle cannot follow because of its small hole).
This way I was able to detect washing machines that have a physical link to a house from many hundred meters (machine spinning -> house wall shaking -> pressure waves) away. The speed pattern of washing machines when spinning is very unique (several steps over many seconds).
Add this with some GPS PPS frame timestamping and you should have a nice tracking network that doesn't require a lot of bandwidth. But maybe the setup must switch to analog differential pressure sensors as these Senirion-I2C sensors do not have a Sync ping for super precise timestamping.
They are getting better.
After a long time they introduced ONVIF into their camera products which basically opened it to everyone.
And screaming loud Keygen music
Streisand effect
Deepseek.v4.Pro.RePacked.LLMBoyz.part1.zstd
I just wait until a Opensource model inhaled all the chemistry books and papers. Lol.
They are following closely and the best offer 80-90% of the performance and come with a very small fraction of the costs.
Freshly marinated in DEET
With Wi-Fi 8 we will finally get steerable friendly roaming like cellular radio is doing for almost 40 years now.
This "here's a neighbor table, disassoc and fuck you&good luck"-method we must use right now is just super painful. It's super complicated to build reliable networks that way.
For sensor stuff use LoRaWAN + Mirotik Basestation + Chirpstack
All ham radio repeater groups here dropped Meshtastic as it was super unreliable. And they know how to build proper antennas and filters.
Meshcore is 100% free. The last issue was the closed sorce Android/iPhone client - but there are FOSS Flutter based-Opensource clients available (https://github.com/zjs81/meshcore-open)
With GNSS+PPS and a hardware timer latch you can easily sync internal microcontroller timers to 2 to 3-digits nanoseconds against the global standard with a tightly controlled loop. But cannot get better than the PPS signal itself (roughly 30-100nS).
Everything below needs that a huge amount of engineering. CERN&friends developed the "White Rabbit" (https://ohwr.org/projects/white-rabbit/) system for this. This allows sub-Nanoseconds syncing of netwoked devices.
The NICs need supported hardware timestamping. Then they can be used with ptp4l.
Intel i210 and i226 does this. But the i226 has a few variants.
Reminds me a bit of the research dept of the company I'm working for.
If they have too much free time they put much weirdo stuff into their devices just to see what.. happens.
They have a spectacular collection of crystals scanned.
Interesting. In safety components we are using Lockstep Microcontrollers which are doing something similar in a much smaller scale.
https://en.wikipedia.org/wiki/Lockstep_(computing)
Example: https://www.st.com/resource/en/datasheet/spc574k72e5.pdf
Gitea Upgrading.. replacing binary, restarting. I love it.
Same for Forgejo.
Wifi HaLow 802.11ah
LoRa is another level. It works down to -146dBm.
802.11ah dies around -100dBm.
Still much much better than "standard" Wifi. But you are comparing two different beasts.
If you want to build sensor stuff you should have a look a LoRaWAN.
Get a basestation from Mikrotik and use Chirpstack as backend.
This setup is commercially very very battlefield proven.