My toddler loves planes, so I built her a radar

Another fun project would be to build your own ADS-B receiver!

https://www.adsbexchange.com/ways-to-join-the-exchange/

Just a few weeks ago I got interested in this as well ("where does FR24 get its data from?"). I ended up buying a cheap RTL-SDR dongle (R820T2) and a small outdoor antenna. I run the free dump1090 tool (I'm on Fedora) to decode ADS-B messages, then my own simple "radar-like" visualization program ([1]) connects to dump1090's network socket to receive decoded data (SBS1 textual format). Even with the antenna just sitting in my room (on a photo tripod), I typically receive data from 10-20 aircraft, up to 190 km away. I drove to a hilltop this weekend (some 600 m higher) and immediately got >100 aircraft, up to 500 km.

[1] https://github.com/GreatAttractor/plane-tracker

I don't have any experience with it myself, but you can provide your ADS-B data to ADS-B exchange. https://www.adsbexchange.com/ways-to-join-the-exchange/

Heads up - IIRC ADSB-exchange was sold out, an alternative might be adsb.fi

Regardless you can send your ADS-B data to all of them - ADSB-exchange, adsb.fi, flightradar, flightaware, etc.

That way you get all of the benefits and contribute community data.

aiui there was some kerfuffle over adsb.fi DNS ownership - I think https://airplanes.live is where the OSS community gravitated.

Ah I've been out of the loop - thanks for correcting me!

The ADS-B Exchange situation is more complicated than it "was sold out," and there are valid reasons for not wanting to use them–but it is still the most comprehensive source of uncensored flight tracking data.

If you share your data with these sites, they usually give you premium access for free.

https://www.flightradar24.com/premium

I share ADS-B data, how do I activate my free Business plan subscription?

Please sign up for a free Basic account using the following link using the same email address with which you registered your feed. Once your feed is live, your complimentary Business subscription will be activated.

I see your use of rust, and I have to mention I designed a Rust ADS-B decoder and TUI radar application myself ([1])

[1] https://github.com/rsadsb/adsb_deku/

Thanks, good to know! Looks like I'll switch to dump1090_rs.

I set one up a few months ago and was really surprised at how much coverage I got–I thought I might need an outdoor one, or at least to fiddle with it a bit, but even just plopped on my desk behind my computer screen on the ground floor of a three story house in a dense area I’m picking up planes from miles all around.

I built a little app that processes the data to count how many are flying low over the park nearby, so I can go there when it’s quiet: https://noisy.today/prospect-park/

I have done the same thing in C# and ArcGIS maps.

I'm going to test it out in an airplane. My map is dynamic, doesn't have to be stationary, and works offline.

Not as fun as building your own, but note that you can apply for a free receiver from FR24.

https://www.flightradar24.com/apply-for-receiver

That's incredible, whats the catch!?

I reckon if I shelled out for a business plan I could start doing some simple stuff with free tier / extra paid features

That's incredible, whats the catch!?

They prioritize low-coverage areas (no idea how generous they are for covered areas).

Nearly all of their position data is from these receivers, so you're providing them with more coverage/redundancy for the plane positions.

The hardware is relatively cheap (under 50$) and I don't imagine the business tier costs them much money.

I reckon if I shelled out for a business plan I could start doing some simple stuff with free tier / extra paid features

You don't need to they'll give it to you for free.

sidenote: You can build your own with an rtl-sdr and a raspberry pi/cheap computer. If you do this you can forward the data to all of the commercial sites for the free perks, and to all of the community sites.

Once you have a receiver, you can use a raspberry pi image like https://adsb.im/home to easily feed data to more than 20 different networks. FlightAware, FlightRadar24, ADS-B Exchange, airplanes.live, TheAirTraffic, etc. Most of the networks give extra privileges to people who feed them data.

That's quite genius, I wonder whether Apple's I/O and Radio APIs will let me do this on mobile...

Mine serves as a fun party trick. I never built this out but I always wanted to build a little display that shows the overhead plane's src/dest, speed, and altitude using the antenna.

So many people say: "Don't take young kids abroad, they won't really remember those travels." BS. I took my son to Brazil, it was great, we got on a $1 cab ride, got on a pirate ship, endless alpine slide after the aerial tram, and went to the Botanical Garden in Rio. (He did say: "that day was totally boring, we didn't do anything!", but I know it was the greatest day of his life, and I can point out all those things to him and he'll not demur).

Later, I took my three kids to Barcelona and Greece. They don't remember the time we took a bus from Athens to the beach and they were rolling around on the dirty floor of a bus, but they do remember the Abba-themed wedding.

Those experiences matter.

Very off topic, but I +1 this. I am half and half and as a baby and young kid we went to one spot every summary. To this day I remember these travels. They matter a lot indeed.

That's great to hear. I think my kids recall the experiences, but you do, and you were a kid doing that. In twenty years I hope to hear the same things from my kids.

I mean, I’m not half, and I never went further than +/- 200 km from my hometown until I was 23 years old, but we did go on vacation somewhere every year.

I _still_ remember all that travel too. It was different enough to make a lasting impression.

99% of our life is spent in the same 2 sqkm area, so it’s not super surprising that everything else is different.

It's a mixed bag really, whatever you do with them has to be memorable for them. My wife is super into travel, our kids (teenagers) have been travelling internationally every year of their life from birth, sometimes multiple times a year.

What do they remember? Almost nothing before they were 10 years old. A core memory here or there, but they can't even recall entire trips from then. But I've always just considered it as part of their development. Maybe they don't have actual memories, but who can say how else it developed their brains?

I don’t think it really matters where they go, as long as they enjoy themselves there.

My 5yo regularly flies across the world back to my home country, but it’s just another place to him. The important thing is that his uncle is there, not that it’s on the other side of the world.

There’s no concept of going to the other side of the world, beyond it taking ”a very long time” to get there. And why would it? The plane might as well be a teleporter.

Depends on the age. I took my 4 and 3 year old to Disney World and they don't remember anything. On the other hand, since Age 6 and onwards, they remember most of the stuff. So you cannot make a blanket statement and need to take Age into account.

I like to remember that we are formed by many things that we don't consciously remember.

Even if my kids forget them all, I won't.

The first time we traveled internationally with our kids (a 5-year-old and nearly-2-year-old twins), my wife and I assumed the kids wouldn't really care, but we'd go anyway because we didn't want to give up international travel for a few decades just because we have kids.

They absolutely loved it. Now the 5-year-old is 15, they've been joined by a couple more siblings, and (Covid-execepted) we've gone on at least one international trip every year.

One of my favorite lines from one of my favorite books is in "A River Runs Through It" when the narrator says, "When I was young, a teacher had forbidden me to say "more perfect" because she said if a thing is perfect it can't be more so. But by now I had seen enough of life to have regained my confidence in it."

I recently went through a decade of photos to see if I could unearth memories of the "more perfect" moments in my life. Nearly all of them were on those trips with my kids.

There's something uniquely "us against the world" about international travel as a family. Not that we approach the world antagonistically, but just in that traveling across borders, and making our way through airports, and figuring out unfamiliar mass transit systems, and navigating unfamiliar cities in languages we don't speak requires a level of coöperation we're not usually called upon to exhibit as a family.

I'm sure there are times it's brought out the worst in us, but they're far, far outweighed by the times it brings out the very best parts of being a family.

"uss against the world" is great way to put it, and it's especially great to see the kids adopt that as they explore something new. Three brothers could be fighting, annoying, etc. right up to the point when they realize that there is safety in numbers. I still remember them exploring a square in Cartagena when the oldest one was 10 and the youngest 5. They would see something interesting little bit further away from us (parents) and would look at each other and decide whether to engage. They ended-up making new (temporary) friends, getting seeds to feed birds and more as they built their confidence while looking after each other.

For the coming summer I've promised to get the two oldest (now 18 and 15) plane tickets to Madrid, Interail (Eurorail) passes, and flight back to US from Helsinki 3 or 4 week later. They'll figure it out, have fun and hopefully don't do too much dumb stuff. Way to bond before the oldest one leaves to college. The middle one gets to do similar trip again in 3 years when he graduates with his younger brother; who in turn will have his trip one year later (hopefully his oldest brother will be available to join him so that everyone will end up with 2 trips with each of their brothers).

My kids have been to a lot of places, and have been questioned about the logic of taking a 4-year old to Machu Picchu or wherever as they won't remember it.

I've said that it doesn't matter if they remember it. It's much more important that they experience it.

You can only experience Rome as a four-year old when you are four years old, there is no chance of getting that experience ever again their lives. They can experience Rome again, and again as an adult if they want, but being 4, 8, 12 or teenager at new place is not something that anyone has a chance of ever repeating.

They remember somethings, forget others, but come away with an interest in people, places, environments, etc.

Along with taking pictures, they'll probably remember it better if you make a scrapbook for each trip and look at it every so often after getting back.

So much this, and you never really know what kids will remember.

Our 8 year old doesn't remember life before her siblings. She was 3 when they were born. To her it's like they were always here. She doesn't even remember her 4th or 5th birthday parties. But starting around 5.5 years old she remembers a lot more.

Our niece supposedly remembers life before our oldest. She was 3 when she was born. I think a big difference though is she had the continual disappointment from then on of not being the only grandchild.

I don't think it's strictly the experience in a memory facsimile, "let me quiz the kids" format that matters. There are a mind boggling number of new and unique data points and methods of delivery kids are exposed to during travel which is really healthy for a developing human mind to have as part of its growth regimen. Travel is one of the last things I will cut if times get tough for our family, before essentials such as food and shelter.

Advice for a wholesome activity with your daughter: Bring her to the closest road/parking lot/park at the inbound end of your closest international airport runway (Typically this changes based on wind direction). Park and watch the planes come in and land. She can use her "radar" to see which planes are coming in (we used flightradar24). My kids were FLOORED how close the planes get to the ground on approach - especially the bigger jetliners. Easily entertained for hours and had to bargain with them to leave because they wanted to see if the next plane was bigger/closer than the last.

And if you're in the D.C. area, Gravely Point is the place for this. Feels like you can count the rivets for planes on either departure or landing.

For Logan airport in Boston, Revere Beach is one place with a pretty good view of airliners, and is short walk from the Blue Line.

You can also see a bunch of other places on a map that line up with runways: South Boston (including Castle Island), East Boston, and a bit further from Logan is the harborwalk around Long Wharf and the aquarium. (The aquarium might also be interesting to kids. There's some free viewing windows for a little of it, while walking past, to maybe gauge interest before paying admission. And there's various tourist things in that area, including various harbor boat rides.)

A camera/cameraphone with >1x lens will get them a closer look at planes. Or binoculars/monocular if you want to reduce screen time, or to encourage appreciating it in the moment rather than trying to capture it. (What kind of hearing protection works for kids?)

Going to Pearson airport in Toronto with my dad is one of my few early childhood memories. I don’t know exactly where we were but it was a popular enough spot that someone had set up a hotdog stand. In my mind it very clearly registers as a scene from the 80s. The aircraft everyone was hoping for was the 747. I still remember the roar of that thing coming in.

Rush fans will know this, but part of the HN crowd won’t and likely find it interesting: there’s a musical connection between Rush’s YYZ song and the Morse code identifier transmitted from a nav beacon at the Pearson Airport (IATA code YYZ)

https://en.m.wikipedia.org/wiki/YYZ_(song)

I recently found out you can do that on one of the roads to the entrance of the Smithsonian Udvar-Hazy museum in Dulles. Nowhere near as Gravely Point, but it will do in a pinch.

Bring some earmuffs.

That's a great shout, I'll see about getting the DLR near to London City this weekend!

Not quite the same as your suggestion but SFO has a Sky Terrace pre-security that you can go and watch planes from.

From experience there is a terrible kerosene smell, I wouldn't advise spending hours. Maybe in a car with closed windows

In the author's case, I think that will be London City Airport (LCY), which has an extremely steep approach.

Only multi-engine, fixed-wing aircraft up to Airbus A318 size with special aircraft and aircrew certification to fly 5.5° approaches are allowed to conduct operations at London City Airport.

https://www.youtube.com/watch?v=yZIDFgpT0-o

https://en.wikipedia.org/wiki/London_City_Airport

When I was in high school, there was a gravel lot just outside of the airport perimeter fencing at the end of one of the runways. When the wind was going the right direction so that the airplanes were taking off over that lot, it was the place to park and make out.

I wrote a simple program that connects to (default) port 30003 on dump1090-fa (Flightaware version). It parses the ADS-B output and uses Flightaware's AeroAPI (there is a free tier based on requests) to augment with airline, aircraft, and city departure information. I then publish to my MQTT (Mosquitto) broker for planes within 2.1 nautical miles (i.e. I can visually make them out).

An MQTT client on an RPi3 (Linux) subscribes to those messages and uses a TTS service (Azure) to generate a wave file. I then use USB audio (this might have been the hardest part) to play it to me while I sit on my patio and watch local planes fly by.

I live near a couple major airports, so most of the planes are easy to spot (~5000 MSL). It's a simple pleasure.

That’s great, do you have a write up somewhere?

I'll finally get motivated and share :)

When you do, I'll be eager to try it, as I currently rely on FlightAware's local web display to show my 3 year old what planes our antenna is picking up.

I just realized I have the transform of the dump1090-fa data to MQTT message already written up: https://github.com/idatum/adsb2mqtt What's missing is the client that enhances flight info and uses TTS to play the generated wave. I also wanted to play around with Home Assistant's TTS. I'll get motivated to write this up more fully, blog style.

I have an iOS shortcut that anyone can use to do something similar. Install it, name it "What's Overhead", and then you can say "Siri, what's overhead?" and then Siri will speak details on whatever aircraft is closest to you.

I use it when driving, or via my watch if I hear an unusual plane or helicopter and don't want to pull out my phone.

https://www.icloud.com/shortcuts/92f43e8881ce4291b48b28a4b0b...

Great idea. Simple but effective, I'm up on a mountain with weird military traffic here and there, in addition to commercial stuff, so I'll play with this when I am driving around for sure.

then use Linux USB audio (this might have been the hardest part)

Linux Audio is ALWAYS that hardest part.

Linux Audio is ALWAYS that hardest part.

Only if you're not using ffmpeg or (c)vlc.

I did this too! - and built out an Alexa skill so I could ask 'where's that plane flying to'

This is great. On my « one day » build list.

In a similar vein, my 5yr old son has a flight log book - I started it for him as a baby. Every flight he gives asks one of the crew if the captain wouldn’t mind completing it. It logs route, aircraft and any events that happened. The crew _love_ this kind of thing - we’ve toured cockpits and crew rests and the messages are always gracious. He’s always beaming to get it back. Highly recommend it for little plane geeks.

That's genius, being invited into the cockpit felt extremely cool even as a grown adult, so I will absolutely get this started next time we get a flight

I thought that after 9/11 passengers were not allowed to visit the cockopit any more

perhaps, but my 10yo son was invited to land in the cockpit earlier this year. he loved it and will never forget it.

(domestic flight, Europe)

Yeah always at the gate upon landing - sigh, I’d love to jump seat to satisfy my curiosity

They are not allowed in there during the flight. When the plane is turned off and parked at the gate, the rules are a bit more relaxed.

My father started a logbook for me when I was a toddler which I still keep updated to this day (I'm in my 30s). Every flight I've ever taken is in it. It's a really neat idea.

That is so cool. I often wonder if I’ve been on this aircraft before, wish I had that data!

+1 on the logbook. We took my daughter London - New York when she was ~8 weeks old, and got some great photos from the cockpit, including her wearing the captain's hat.

Nice! Minor nits:

* It takes me out of the immersion a bit when planes move after having been drawn. It would feel more realistic if the blips were "painted" by the sweep and then static until the next sweep.

* To make it a bit more realistic you could extrapolate from previous data points so each plane would make consistent progress from sweep to sweep.

Thank you :)

Both very valid points. I think if I was clever with timing and angles the first one is definitely doable. The second one woudl be even simpler - the API returns flight velocity so I can even calculate this from one data point

I suggest adjusting your gradient so they don't fully fade out until just before the sweep hits them, or maybe even only down to 10%, so they only get wiped by the bar. It'll make it much easier to watch a plane if it doesn't keep disappearing entirely.

On the other hand, if you want maximum realism, everything should fade continuously from when it is drawn.

The underlying technology being imitated here is a slowly decaying phosphor.

Not sure if you picked up your own slight mistake earlier, but this is also exactly why you shouldn't try and 'tween' the planes to the new positions if you're aiming for realism.

Huh? What I'm proposing if you want to make it realistic (which may or may not be good UI) is:

* Everything fades from when it was drawn

* Everything is only drawn with the sweep

* Simulate a continuous motion for the planes, and use that to determine a new position at each sweep.

Did I make a mistake?

On re-reading it seems more like I misunderstood.

I thought you were saying to animate the planes, but I no longer think that's what you meant.

And this is why I still hang out here, after abandoning nearly everything else.

I love how a discussion like this can occur here and there's no flaming or egos getting hurt. When you post a labor of love like this, it's great to see the reaction on HN.

I spend a lot of time trying to decide what to do with old tech in my volunteer gig. We have old Univac "dumb" terminals and I feel the need to plug them in and see if they still work. I come here for re-charging.

I think emulating old hardware is fascinating. Am I the only one who watches old media just to hopefully get a glimpse of the past?

Thanks for this comment - I knew the exact visual effect I was going for but didn't actually know the physics of what is happening until now! :)

I love the design but go one step further - forget the API and get an SDR that is tuned to ADB frequencies at 1090 Mhz and gather the data yourself. Then she'll have a true radar.

Edit: fair point on what a radar is, today I re-remembered :)

Disregarding the other replies for a moment where they rightfully call out that it wouldn't be radar, wouldn't they still need a publicly available API for this data if they wanted to access it outside of their house (e.g., when at the park)? So at that point, why add the additional complexity if there's already someone sharing ADS-B data to OpenSky for your area?

Why add the complexity? Cause you can. You can also submit the data to contribute while at the same time receiving and displaying it in their webpage.

I have an Android phone with an OTG cable and SDR Touch and ADSB# - that lets me "see" any plane transmitting ADSB signals around me without any need for a network connection.

(I use that as part of my safety setup when flying drones. If I'm out of cellular connection or my iPad running FlightRadar24 fails, I have a backup self contained plane detection system.)

Nice app and writeup - but she won't have a radar - she'll have an app that displays the positions of airplanes. A true radar needs to transmit and receive.

The SDR is still just listening to the telemetry from the plane, which they transmit all the time for this ADS mode.

TIL what a radar is :)

You can have passive radar:

https://en.wikipedia.org/wiki/Passive_radar

But yes, it needs to be doing more than receiving telemetry to qualify, and there has to be something transmitting.

That's a great shout, somebody even suggested I could become a contributor to FlightRadar and get a free transponder receiver!

Which begs the question, why can’t Google Maps ever work out which direction I am facing?

I always wondered this as well. Apple Maps seems to be much better at this

My Apple maps consistently has me 90° off from where I'm actually pointed.

My man at Apple Maps forgot to account for Header

It used to do it fine and then they had an update that made it terrible. You need to hold your phone flat, if it’s at even a slight angle it stops working.

Right! I was expecting it to be hard, but I literally get my orientation streamed by CoreLocation

When I was in Tokyo I noticed that the compass was completely useless. Too much EMI?

But, in order to make sure she could handle the 3-hour flight, my wife and I made sure to hype up the airplane journey. So much so, that my toddler was shocked when we had to get into a cab for the airport — she expected to walk straight from our house onto a plane.

This is absolutely adorable, hilarious and understandable at the same time.

Fun fact, there's a swanky gated community in Florida where you can do just that:

https://www.architecturendesign.net/john-travoltas-house-is-...

Fly-in communities are actually pretty common as far as aviation stuff goes. There are probably several hundred in the US.

But most of them have runways made for small general aviation bugsmashers, not 707s.

While that sounds like a great concept I'd be worried about the constant lawnmower tier noise that GA planes make over my home.

Haha yeah, I think by the journey back she started to get the hang of it

This is great!

Small detail question: Did CRT radar scopes really have scan lines? I would have guessed they were vector displays.

Re. list of extra features: Since the app targets planespotting, it would be cool to show aircraft type, maybe for a few seconds after you tap a blip.

They were vector displays. But possibly not quite in the way you're thinking.

The original radar displays would scan from the center outward along a radial. The timing of the scan was predefined to scale for distance. The beam intensity signal was directly the (amplified) radar return signal. So a stronger returned signal would cause a more visible "blip" on the long-phosphor display.

The interesting part is to make the radar beam scan around the CRT display, the whole cathode tube emitter assembly would be driven by a motor synchronized with the spinning radar dish. This rotation would have to match the speed and direction of the radar dish at all times, otherwise the blips would show in the wrong place.

The fixed radial and distance lines would be printed either on the CRT tube itself or on a transparent cover. Displays like this were used for decades, probably well into the 1980s or even early 1990s. Newer versions were able to use simple electronics to scan in the X and Y direction independently, to avoid the more complex rotating beam emitter assembly.

More info at https://en.wikipedia.org/wiki/Radar_display#Plan_position_in...

I was wondering about that after asking my question, since converting the signal to an x/y scope requires trigonometry. Probably a challenge to do electronically in the early days of radar. Leave it to the WW2-era engineers to find an electromechanical solution!

Radar was surprisingly advanced by the end of WW2, the Brits and Americans had ground scanning radar by the end of WW2 (H2S and the later H2X) all done without transistors or computers as we'd recognise them :).

Just to expand on one point the other two replies touched on: The beam does indeed scan radially outward from the center (though the angle can either be produced by physically rotating the deflection plates, or computing sin/cos electronically and applying to the x/y plates), and the amplitude of the returned signal does directly drive the beam current (so a target with a larger return will appear brighter.

Additionally, there's also a storage tube effect going on, too--but it works like the variable-persistence mode found in certain oscilloscopes, not the bi-stable mode found in storage-tube x-y vector displays for early computers (some o'scopes had both var persist and bi-stable modes).

One consequence of the above is related to early attempts at designing stealth airplanes, like the SR-71 and XB-70: The beam current is set such that the radar tube tends to build up the "blip" over multiple sweeps, and the blip usually moves less than its own diameter between sweeps.

But, if the airplane has an intrinsically low radar cross-section and if it is moving so fast that the blimp moves a greater distance between sweeps... the radar operator may just interpret the little ghost blips as noise, especially if he or she is overwhelmed by a large number of targets.

No, you're right. Old-school radar displays were basically like oscilloscopes where the X and Y position were controlled by the angle of the radar, and the current range of the radar return. So it's a type of polar plot.

The phosphor afterglow made it so that stronger radar returns remained on the screen for a bit. If the radar made more than a revolution in that time, you'd see the same airplane as a new dot ("plot") that had moved a bit. You could use a felt tip pen to mark the plots as "tracks" on the screen.

There were also special radar screens with a movie camera pointed at them, where hours of radar returns could be recorded for later playback.

For instance this sped up recording of Warsaw Pact planes during the 1968 revolution in Czechoslovakia: https://youtu.be/rAUodXI4LPw?t=622

This is cool in concept, but FlightRadar24 has a built-in Augmented Reality feature that works really well.

https://www.flightradar24.com/blog/show-us-your-best-augment...

Also, if I were to build my own local copy, I'd use an RTLSDR to get the ADSB packets direct and base my app on tar1090. https://github.com/wiedehopf/tar1090

what children truly want, need, and enjoy, is interaction with adults, and the less augmented the reality of the human contact, the real-er it is. build something that doesn't work so well with them, rather than off the shelf something perfect.

Now I'm just thinking about how I'd put a CRT filter on AR planes

This rings true. I remember the wooden toy biplane my dad made in his wood shop when I was a kid a lot more fondly than all the other bought plastic toys that came after it.

MSFS (MS Flight Simulator) has real-time Flight and Weather data and works in Steam's Proton fork of WINE on Linux.

FWICS there are third-party open source tools for adding live Flight data and logical behaviors to flight simulator applications.

https://fslivetrafficliveries.com/user-guide/ :

FSLTL is a free standalone real-time online traffic overhaul and VATSIM model-matching solution for MSFS.

(... Til about FlyPadOS3 EFB: An EFB is intended primarily for cockpit/flightdeck or cabin use. For large and turbine aircraft, FAR 91.503 requires the presence of navigational charts on the airplane. If an operator's sole source of navigational chart information is contained on an EFB, the operator must demonstrate the EFB will continue to operate throughout a decompression event, and thereafter, regardless of altitude. https://docs.flybywiresim.com/fbw-a32nx/feature-guides/flypa...)

https://twinfan.gitbook.io/livetraffic/ :

LiveTraffic is a plugin for the flight simulator X-Plane to show real-life traffic, based on publicly available live flight data, as additional planes within X-Plane. [...]

I spent an awful lot of time dealing with the inaccuracies of the data sources, see [Limitations]. There are only timestamps and positions. Heading and speed is point-in-time info but not a reliable vector to the next position. There is no information on pitch or bank angle, or on gear or flaps positions. There is no info where exactly a plane touched or left ground. There are several data feeders, which aren't in synch and contradict each other.

...

"Google Earth 3D Models Now Available as Open Standard (GlTF)" (2023) ; land, buildings: https://news.ycombinator.com/item?id=35896176

https://developers.google.com/maps/documentation/tile/3d-til... :

Photorealistic 3D Tiles are a 3D mesh textured with high resolution imagery. They offer high-resolution 3D maps in many of the world's populated areas. They let you power next-generation, immersive 3D visualization experiences to [...]

GMaps WebGL overlay API: https://developers.google.com/maps/documentation/javascript/...

...

From "GraphCast: AI model for weather forecasting" (2023) https://news.ycombinator.com/item?id=38267794 :

TIL about Raspberry-NOAA and pywws in researching and summarizing for a comment on "Nrsc5: Receive NRSC-5 digital radio stations using an RTL-SDR dongle" (2023) https://news.ycombinator.com/item?id=38158091

...

"Show HN: I wrote a multicopter simulation library in Python" (2023) https://news.ycombinator.com/item?id=38255362 :

[ X-Plane Plane Maker, Juno: New Origins (and also Hello Engineer), MS Flight Simulator cockpits are built with MSFS Avionics Framework which is React-based, [Multi-objective gym + MuJoCo] for drone simulation, cfd and helicopters ]

...

"DroneAid: A Symbol Language and ML model for indicating needs to drones, planes" (2020) https://github.com/Code-and-Response/DroneAid https://news.ycombinator.com/item?id=22707347 ... https://github.com/Call-for-Code/Project-Catalog

That is very awesome, TIL

If I were commercially-minded (I'm not), I'd go full hog on the Mattel approach and carve out the niche as a toy vs an informational product

I didn't know they still let children into the cockpit anymore!

I believe they still do after and possibly before the flight. They used to do it during the flight!

I've done that! It was on what I think was my first commercial flight, a 767 from probably YVR to LAX sometime in the early 80s. My grandfather was the king of getting kids into fun places, he would go talk up the crew (of the plane, ferry, train, whatever), then come back and fetch whichever grandkids he had.

Sadly those days are long gone now.

I did the same on my first flight, England to America. I was very shy with the loud American pilots, but I'm sure I wasn't the first shy English boy they'd met.

This was in the mid 1990s, and the cabin crew invited me to look. I don't think there were many children on the plane.

I think only when the plane is grounded.

This would be right!

Off topic but you have my exact name (first and last). I wonder what the chances are on that.

numerically, quite low, but given the number of people on the internet, it happens routinely. I'd guess most English speaking people have used <internet_search_of_choice> for their name and found duplicates So:

guess maybe 100 million English names on the internet, between 2 and 100 matches, so around 1 in 10 million

BTW. I got bored counting the matches for Jacob Bartlett on facebook. definitely more than 10

I've never met anyone (outside known relatives) with my spelling of surname. When I moved to my current UK city I was surprised to find a Firstname Lastname match in the same city.

Facebook shows dozens of the same name in the general area.

As I've seen some say, if you're one-in-a-million then there's ~7000 people like you out there somewhere!

Jacob and Bartlett are both relatively common names, I'd say aggregating over a lifetime one can expect to coincidentially bump into quite a few over the years (since the advent of the internet at least!)

You in particular, pretty low. But open up the names to be any first/last combo, and we have the Birthday Paradox.

My name is quite a bit more unique than Bartlett, and I still know of about a dozen people with the same first/last as myself. I thought about setting up an FB group named after us and inviting them all just for funsies. None of us are related as far as we can tell, but the name is unique enough that we probably are, if only distantly.

Us Jacob Bartletts gotta stick together

I swear there are startups that blabber for years before making an MVP.. Jacob was able to build this in a cave, with a box of scraps..

In the interests of appeal to modesty, I can tell you about my long history of unreleased apps, failed startups, and false starts :)

if you're anything like me, you have a stash of items that you just haven't gotten to yet but have every intention of doing something with at some point. law of averages suggests one of them will hit!

I'm not Jacob Stark...

Nice work and nice writeup. It's interesting to me how strongly the design of original radar displays anchors the project. Your toddler might never interact with a real CRT, much less an ASR-9 with a PPI display. But you've gone to great lengths to simulate one for her.

Partly because of your affinity for skeumorphism, as you said, but it may also be because the OG radar display is a fantastic distillation of "Is there something in the sky and where is it relative to me?" All the UIs we have for sky-watching now have moved away from that in favor of contextual data or linking out to other services (or creating space to display ads). In the process of presenting all that additional information, they've lost the ability to easily answer that particular question.

I like your comment — it points out that our RADAR displays were a both a product of the technology that was used to generate them (the sweep) but also that it was a deliberate way to make clear what it was you were observing (target distance was represented by distance from center, target bearing by angle around the circle).

To your point though, perhaps emulating the sweep was the questionable design decision — the bright colors, map-less background not controversial at all since they help focus on the intent of the display.

I did notice that as I turn with the phone, the compass-tracking feature broke the illusion of the sweep. :-)

Now I have a funny vision in my head of a WWII radio tech standing in a field, wearing an absurdly large RADAR rig, with a big sweeping antenna protruding from a backpack and a massive screen on his chest, turning this way and that, all confused by how the sweep doesn't look quite right...

All the UIs we have for sky-watching now have moved away from that

Check out SkyMap!

https://github.com/sky-map-team/stardroid

Really appreciate the feedback :)

I think I was very well served by having a very pure motive: What direction should I look to find a plane, and worked up from there.

I occasionally get large military transport planes that buzz my rural area at very low altitudes, often below my house in a canyon just a 3 iron away. I suppose they're training. The roar is epic. It'd be nice to get a little notification when that's about to happen. Not enough to write my own app for it though. Kudos for the hustle.

That's a really great little niche market, it's times like this I wish I was more entreprenurial

Thank you for the kudos :)

The military planes are hit or miss for what they put out in terms of position. Most will do Mode S transponder, which does not, by itself, include position. But if you get enough of these ADS-B receivers in an area, they can triangulate the position.

Every few weeks we have "mean jets" (what our 3 year old calls fighter jets, I think from the Iron Giant) buzz our house near KBJC going in for landing/taking off. They're super loud and often gone before you can get outside to see them (they leave at 400+ kts).

We get similar here and it's on my (long) todo list to set up a notification for low incoming planes.

Slightly off topic: I went to download this and it said I needed iOS17. Out of pure curiosity what from iOS17 does it need? Apologies if it’s mentioned in the article, I just skipped ahead to final product.

It is mentioned in the article -- the app uses new APIs in iOS 17 for map annotations.

Correct, also SwiftUI Metal Shaders (about which I've written an upcoming article) and SFSymbol animations

Not off-topic at all, happy to answer!

- Map Annotations - SwiftUI Metal Shaders (for the CRT effect) - SFSymbol Animations

If I remember anything else I'll mention :)

OK very nice, but I had brief hope of a home built primary radar featuring a microwave oven magnetron :-)

Same. Cool project but way less interesting.

Apologies, I hope the title didn't go to far on the clickbaity side

Haha when I get on a hardware kick I'll give it a go

Careful. This will be tolerated right up until you start building fire-control radars, at which point people with absolutely no sense of humor may take an unhealthy interest in you.

"A fire-control radar (FCR) is a radar that is designed specifically to provide information (mainly target azimuth, elevation, range and range rate) to a fire-control system in order to direct weapons such that they hit a target. They are sometimes known as narrow beam radars,[1] targeting radars, or in the UK, gun-laying radars. If the radar is used to guide a missile, it is often known as a target illuminator or illuminator radar."

https://en.wikipedia.org/wiki/Fire-control_radar

That was a new one for me.

Maybe I'll make a lucrative exit to the military-industrial complex

Great minds… I published something very similar (albeit less advanced) that also went viral on HN back in September: https://news.ycombinator.com/item?id=37379801

Mine is a webapp 80% generated by GPT that makes a sound when a plane enters a certain radius around the user’s location.

Oh awesome! Great minds indeed :)

Honestly building a toy for my toddler is some of the most fun I've had coding in years, I can't wait for her to get a little older and start articulate her own ideas

I feel you. I have all kinds of ideas for when he gets a little bit older. For example: a voice-controlled (perhaps motion activated) electric train. I think having a child gives me an excuse to express my inner child's passion for tinkering.

Love the design, but super uncomfortable with giving phones to toddlers as toys. For mine, the longer I can put it off the better. There are enough infants bumbling around the world already glued to screens, in imitation of their zombie parents (this is a general observation, not levelled at OP). For the inevitable “but kids need to learn how to use phones as tools” - tools for what? They are designed to consume you and your attention. I also don’t regard the ability to halt a conversation while you ‘look something up’ as a benefit.

Very reasonable point to be fair, and I agree with you. I certainly would not be comfortable building something for a kid to stare at that had no relation to the real world

Is that really what's happening here though? Seems like the author is using the app with their toddler, and it's only a tool to do something in the real world.

Kind of made me think of my dad teaching me to use a compass or looking at star charts with me in the early 90s.

If anyone is interested, you can build your own adsb receiver for very cheap (under 50$), and you can forward the data to all the platforms - ADSB-exchange, airplanes.live, flightradar, flightaware, etc.

You'll get the business tier plans on the commercial sites for free, and you'll feed the community exchanges.

You'll also be getting the data directly, so they aren't censored, and don't rely on the internet.

I bet this'd be a lot more reliable than the free API I'm using

(no hate to OpenSky though they were very nice and clear to me when I emailed them)

yep and you also can get multiple updates per second per plane. I think it tops out at 8 or so which is entirely unnecessary for the radar-style app but you can count on an update between each "scan".

https://austinsnerdythings.com/2021/04/18/moving-my-ads-b-an...

https://austinsnerdythings.com/2021/03/09/receiving-aircraft...

I like the idea that changing the display color was a must-have feature for the initial release. Shows a very solid understanding of the target demographic's user needs. (My 3yo loves any toy that includes a color picker!)

Heck, I’m a grown man and I get giddy too when something includes a color picker!

(Imagine my irrational excitement when I surpassed 250 karma here on HN)

Thank you for making me one of today’s lucky 10,000!

https://xkcd.com/1053/

Just wanted to say what a wonderfully uplifting comment thread here in HN all launched by a heartwarming article. Such a pleasure to read of the kids delight, people's travels and fun as kids and with their own children.

+ a billion!!

Thank you :D

It's quite nice the level of positivity, versus some of my other deep technical write-ups which might have a small inaccuracy

Toys are harder to mess up!

This is a terrific toy. Great work!

Thank you :)

Idk why, but this is delightful to use. There’s something so fun about it. Will likely delete after a few days, but just turning it on and seeing the planes appear on a radar-like screen is just charming.

Thanks, that's great to hear :)

Will try not to toot my own horn, but I think the explicit goal of making it a toy vs making a commercialised product with ads/aggressive paywalling meant I could make something simple that gives nonzero value without any baggage

This is perfect. We need more hobbyist apps. Minimalist design, simple and solid functionality, and no ads in sight. Shake off the shackles of the advertising dystopia!

This comment is perfect :)

I think certianly the toddler-based inspo made it easier to turn into a simple toy

My son loves this app and he’s 7. Thanks!

A small gripe, I’m unsure whats the api refresh rate and my kid continues closing and opening the app and then it sporadically gets time outs on the API. That being said, I much appreciate taking the time to release it and blog about it.

That's awesome, glad he liked it!

Very fair - the OpenSky API has no SLO, so it will sporadically fail to reload. I'm working on better retry logic in V2, and potentially the ability to login with your own OpenSky account (http basic auth)

I see one issue with this app: the app page clearly says it’s only for 4+ yet your target audience is only 2 :)

Nicely done!

I hope to stay under the radar of the app store police :D

Now you get to explain to her in a few years how different ADS-B-based web data (or locally received ADS-B, even) is from genuine RAdio-Detection-And-Ranging (either the old school rotating type or modern fancy PESA/AESA ones).

And she'll forever remind you how your app [name] is a lie.

What a fitting username!

Funny, I just re-watched the Gener8 DD pitch yesterday coincidentally and checked out where you guys were at since then.

Great write up! Just need to upgrade my iPad OS to give it a spin

That's awesome! Any feedback on the apps are welcome

My first initial thought to this headline was he actually built a radar for his own curiosity, not because their toddler loves planes.

It's a little clear which of us got more out of the project

The apps doesn't work for me. Connection is timing out.

Sorry about that - the free API has no SLO, so sometimes you need to check back later on to get it working!

V2 will allow you to use HTTP basic auth and your own OpenSky account

the crew spots you with a cute plane-obsessed toddler, they invite you in to check out the cockpit.

Matching NASA orange jumpsuits are the passport into every cockpit. The crew gets way more excited than the kids. Also makes them super easy to find in the airport.

That's genius, so I just need myself or my wife to get into NASA. Do they need many iOS devs in space?

Interesting how the OpenSky API shows all of the private jets at Farnborough, whereas the flightradar24 UI hides them.

That's a great point! I reckon FlightRadar might have a side hustle of hush money :)

Love it!

From the error message it seems that too many HN users are trying it out right now. I will come back later.

Yeah, the API is free and has no guaranteed SLO.

I think for V2 I'll allow people to enter their OpenSky credentials, since it allows for basic auth

V3 (unlikely unless this takes off, pun intended) I might look into paid services.

Eventually you will be building this:

https://www.euronews.com/next/2021/12/09/retired-man-travels...

That is extremely cool.

I have always planned to make a low-tier version of this for my kid using an old music mixing board

Love the simplicity.

”A Learjet at 40,000 feet shows up the same as an AirBus that just took off at London City Airport, however it’s a lot easier to spot the jumbo jet in the real sky.”

When I use FlightRadar24, I actually see different icons for jumbo jets vs Learjets vs prop planes - so they do not show up the same for me.

Maybe the author means altitude is not distinguished per this quote:

”I added some simple log scaling to the map annotations using the altitude of the flight so higher up aircraft appear larger on-screen.”

After downloading the app, planes high in the sky overlap/hide planes lower to the ground. I wonder if color coding the planes would have been better than using different size planes to indicate altitude.

Eg brown/green planes mean close to the ground, and blue planes mean high in the sky. Then have all planes the same size, and use different plane icon shapes for distinguishing commercial jet vs private jet vs prop

I have this addressed in V2: The transponder gives an approximate size class for the aircraft, so I'll be able to scale them better if I use this

I was hoping he was actually building a radar, but this is not one. Still nice though.

Apologies about that. I hope it doesn't quite fall into clickbait territory

My friend in NSO group is working on hacking the iPhone to pick up transponder signals, watch this space

This is brilliant - thanks for sharing the story. This is one of those ideas that, on the surface, looks really hard to build but your breakdown made it look super easy. Very inspiring :)

Thank you :)

It was probably my easiest ever article to write, since I was simply coding each evening and adding a few cliffnotes, screenshots, and snippets as I went.

When it came to writing, it was just filling in the blanks :)

That's super wholesome. Congrats on app and plane-curious kid

Thank you :)

Related "An app can be a home cooked meal" on cloning the defunct social network app Tapstack for just his family's usage https://www.robinsloan.com/notes/home-cooked-app/

That's a lovely article, bookmarked! Agree, I'd have been happy with zero downloads because the process was rewarding itself.

Going viral also not bad though.

Jacob, what a cool project! It was fun to read, which speaks to your writing skills.

On my iPhone SE (2020) the scan-line effect is distractingly low res (1), perhaps because of my lower screen resolution?

1: https://nexus.armylane.com/files/RPReplay_Final1701128035.mo...

Hey, thank you for the bug report!

I think I know the culprit, my Shader which is applying the CRT effect shouldn't scale the scanlines with screen size, they should be constant sized - I noticed the same issue when you go to the app switcher.

So cute! And of Sunday afternoon a flying saucer with green tractor beam came by to check out what the fuss was about.

"I wanted to make a radar app and here is my toddler for cuteness points"

Thank you for making this!

I have a 1.5yo that’s obsessed with pointing out planes in the sky.

Now we can go plane watching together!

Awesome, thank you for making this app! My 2yo is obsessed with planes too and we spent a good chunk of our day looking up the sky scanning for planes :) We tried the Flightradar24 app too but it is way to distracting for him... can't wait to show him tomorrow!

Very cool and inspirational!

This is awesome! Now I'd like to see an Android version or better yet, a port to something like React-Native, so it can work on any device, iOS or Android!

As a Pilot, this is amazing. Bravo!

My toddler has a similar back story (flight hype -> loves planes). This inspired me to finally upgrade my iOS.

The fade in-out solution was genius! Knowing myself I would've definitely over-complicated it and spent ages writing spaghetti.

I wish my trip abroad took 3hrs ;)

Disappointed that you live in London and choose the wrong spelling for aeroplane.

10/10 Dad

Baked into this post is a glorious example of excellent fatherhood - taking their kids interests (the good kind) and nurturing and fostering them. Using his talent stack to nurture his daughter's talent stack. Good dude.

There's a really cool setup at CuriOdyssey in San Mateo: https://www.youtube.com/watch?v=16vZjWb5n6E&t=1s

My son can spend hours just waiting for planes landing in SFO.

I thought about building a laser system to write on overcast skies at night and realized it would have to have something like this so it doesn’t pass any aircraft.

Was part of a project to put a similar display in the cockpit. Using transponder data which includes GPS location, you could create a radar-like display on a small LCD screen mounted to the cockpit panel.