An ESP32 based plane radar for my desk

206 pointsposted 12 hours ago
by alexktz
(blog.ktz.me)

41 Comments

freitasm

11 hours ago

Well, a radar-like display, then. But not a radar.

NooneAtAll3

11 hours ago

radar *display*

making esp32-based radar emitter would've been cool, tho

boguscoder

9 hours ago

Perhaps I didn’t read it thoroughly enough but it seems that lat/long of the “radar” are expected to be entered by user, I think using wifi positioning could be of great assist and could be done from mcu itself without involving web portal, though maybe portal already does it (didn’t get to see it)

andai

3 hours ago

That is so cool. I don't know what I would do with this but I want one!

amatecha

11 hours ago

Looks pretty cool, though kinda "cheating" by pulling from adsb.fi - though I think you'd need something a lot more powerful than an ESP32 to receive and decode ADS-B ;)

sephamorr

11 hours ago

I would actually expect the math to decode ads-b traffic is substantially less complex than, for example, a TLS connection.

dlcarrier

7 hours ago

TLS is supported in hardware, so it takes no more processing power than moving the data around without encryption.

In the US, ADS-B in uses 1.3 MHz of bandwidth, which would require 2.6 Msps. The ESP32-C3 running at 160 Mhz would have ~70 instructions per sample to process the data. That's probably doable, but the ESP32-C3 is one of the less capable variations of the line, and there are dual-core versions running at more than double the frequency, and those should be able to handle ADS-B in without issue.

schoen

7 hours ago

> TLS is supported in hardware, so it takes no more processing power than moving the data around without encryption.

Specifically, common PC CPUs support AES acceleration, so you can get the ongoing encryption for an established connection with minimal overhead. There is still some initial overhead for establishing the TLS connection due to the need to do key exchange (with asymmetric cryptography primitives typically based on Diffie-Hellman with finite fields or elliptic curves).

windexh8er

an hour ago

Except on small memory / processing devices (like ESP32) it's not actually that simple. Processing ADS-B on an ESP32 would, likely, be easier.

Part of the reason I've come to understand how finicky TLS is on ESP32 is because there have been a ton of TLS issues with these devices in Home Assistant [0]. The linked issue just being one of them that's still not fully resolved.

[0] https://github.com/esphome/home-assistant-voice-pe/issues/31...

cenamus

6 hours ago

GPS is over 1 GHz, but I don't think you need to have a microcontroller running that fast to decode it?

a1o

4 hours ago

I imagine the over 1GHz in this case is the baseband that you are talking about.

ADS-B baseband is also around 1GHz, what they mean is once you down convert in the process of demodulating the signal you will get a signal that has bandwidth of 1.3MHz.

greggsy

11 hours ago

It is trivial to decode, but don’t forget that tls is extensively optimised on most networking stacks.

bigiain

11 hours ago

Using ADS-B and calling it a "radar" feels wrong to me.

(But is is a cool project)

blks

4 hours ago

And not actually receiving ADS-B which requires some radio module tunnable to specific frequencies

daemonologist

11 hours ago

Agreed, and even SSR always felt like cheating imo. I wanna see someone build a primary radar on an esp 32.

bigiain

8 hours ago

Gotta admit that's what I clicked through hoping for.

I've seen a few projects that use SDR to detect doppler shifts of reflections of broadcast FM radio station off planes as "passive radar". But that doesn't get much in the way of direction info, just approach velocity. I've pondered building something that uses that and correlates it with an ADS-B receiver, to see it it can detect aircraft that are not transmitting ADS-B. But that'd get me on another "list" if I published it I suspect...

This is not the project I remember, but it's the same idea and technique: https://github.com/Max-Manning/passiveRadar

phire

5 hours ago

I suspect it's possible to build an active radar without exceeding the limits of the ISM bands.

Actually, I know it's possible, that's how the automotive radars (used for adaptive cruise control) work. The real question is if someone can get enough range to pick up aircraft.

punnerud

11 hours ago

Actually possible to receive and decode ADS-B on ESP32, but MLAT is failing (tried hard but not found a trick yet).

Biggest problem isn’t that it’s not powerful enough, but the USB port bandwidth don’t match most SDR.

Using some clever tricks you can receive parts of the message on a slower USB and be able to decode ADS-B

1e1a

10 hours ago

Why do you need to send the samples over USB?

dlcarrier

7 hours ago

The built-in ADC doesn't have a high enough sample rate to decode ADS-B in, so an external one is needed, and USB ADCs are readily available with built-in demodulators, for use as DVB-TV receivers.

punnerud

6 hours ago

No you don’t need an external one, it’s actually possible to sample parts of high bandwidth using a lower bandwidth because of the small buffer in most SDR. The problem is that you can’t freeze the buffer so have to gather multiple “sweeps” get parts of ADSB stitched together.

Maybe I post the Rust code after some cleanup. Now I am busy build a new database from scratch to compete with them all https://github.com/punnerud/mpedb

greggsy

11 hours ago

You could fit a pi zero and rtl in an enclosure not much larger than the one they’ve printed.

ustad

8 hours ago

“Finally, the firmware now supports authenticated OTA updates, so future builds can be installed through the browser instead of connecting the board over USB.”

What does that mean?

alexchamberlain

8 hours ago

OTA = over the air. ie online updates you’d expect of a more polished product

ustad

7 hours ago

But the browser is involved. Can the browser do OTA to esp32?

waste_monk

6 hours ago

I believe the ESP32 runs a small web server that supports WebSerial (?), if you can reach it over WiFi or somesuch, you should be able to upload the new firmware blob that way.

cenamus

6 hours ago

The browser connects to a webserver running on the ESP32. Over wifi -> over the air. OTA doesn't mean headless or automatic

mlrtime

3 hours ago

I have about 30-40 esp32 / esphome type devices running. Typically to flash or update a device, you would plug it into your usb port.

esphome can also be flashed "OTA" which just means compiling your project locally, then pushing the binary over tcp/ip and giving an instruction to install it.

With https://github.com/esphome/device-builder you can run a network of multiple esphome builders so you can update many devices at the same time "OTA" (TCP/IP).

rbanffy

2 hours ago

It needs a 28 inch display.

kruskakli

7 hours ago

Cool project! Funny how similar projects can pop-up at the same time; here is a somewhat similar project for identifying close-by flights, but this is a mobile app: https://github.com/etnt/skyoverhead

sneak

9 hours ago

ADS-B is not radar, despite ATC calling these sorts of things “secondary radar”.

holoduke

6 hours ago

These kind of project are now so easy. A few prompts and you have something like this. I did it with quite a few similar like projects. You can buy super cheap esps with integrated lcds for less than 20 dollars.

nunodonato

4 hours ago

yeah, I've been dying to do something with ESP32, but still waiting for that idea. Something with eInk displays :D

fsniper

an hour ago

I did vibe coded one, where It downloads images from my (currently defunct) immich server album, dithers them for 4 color inky display, downloads the weather data and display them. It's a fun little one. I wish the inky only had a "faster than 30secs full refresh" partial update capability.