My toddler still loves planes, so I upgraded her radar

Maybe this is pedantic -- Did you build a radar, or did you build a wrapper around an ADS-B API?

I clicked this thinking, "Wow! Radars are hard. Building one at home would be quite the feat!", but this appears to just be a wrapper around an ADS-B data providing service? Not even reading the ADS-B data over the air on one's own at home?

Calling this a radar, vs saying "I build a nice GUI around ADS-B data", are two very different things! The latter is a fun side project at home, but it's a couple orders of magnitude easier than the former!

Listen, if you think handing a kid a cavity magnetron and the multi-kilowatt power supply to drive it ON TOP of a high-voltage CRT display is a good idea -- then I really want to know how it goes.

As someone who grew up around (literally stacks of) analogue equipment, I feel that it's worth noting that there's nothing particularly unsafe about high voltages when they're properly contained. The dielectric strength of air is sufficiently high that you effectively need to be touching the conductor before it will arc. At that point, there's not a terrible amount of different between touching a live 240V AC terminal (the standard where I live and in most of the world) and a live 2000V AC terminal. I'm definitely not suggesting that one should be cavalier about high voltages, just pointing out that electrocution wasn't a big problem in practice for most of the time when these older devices were used.

There several more pressing safety issues with analogue equipment than simple electrocution:

- Fire risk due to the much greater energy consumption of older discrete components. Even the passive losses when in standby are considerable; the need for heatsinks is a given, and ventilation is critical.

- Explosion (actually implosion) risk of vacuum tubes/thermionic valves. There are a surprising number of videos online of people deliberately destroying TVs with overvoltage, but suffice it to say that you do not want one plugged into the mains during a thunderstorm.

- Physical injury. Not really the fault of the technology per se, but it can be easy to forget just how physically light modern equipment is. You can hurt yourself by trying to move older devices. Having the equipment fall on them is probably the biggest risk to a toddler who's not actually trying to take the device apart.

Well, obviously that part would be on the roof, and you would hand the kid something that would, to them, be indistinguishable from the API approach, all as you nervously wait for authorities, from the nearby military base, to come check your intentions.

I know at least three people who are nuts, skilled and moneyed enough to actually build a legit radar system - they're all hams. Only problem I think would be getting a license to transmit on radar frequencies...

"Back in my day..."

Maybe this is pedantic -- Did you build a radar, or did you build a wrapper around an ADS-B API?

To a toddler, it's all the same.

I don't know of any toddlers reading Hacker News.

I don't know of any toddlers reading Hacker News.

You're right, but the thing was made for a toddler and the "radar" label was probably made for them.

Honestly, "radar" is probably the clearest label for something like this for all people who don't know what ADS-B and RTL-SDR mean (which is probably 99% of all people, period).

I wouldn't have any issue if it were worded "radar", with quotes. That implies a likeness, but denotes a lack of precision.

And I think there are more avnerds on here than you would expect!

I don't understand why you're being downvoted. You are correct.

I also don't think you are being pedantic. This is a forum where technology is often the topic of discussion, and in tech words often have very specific meanings. Like radar.

No slight whatsoever to the original author, I liked the post, and applaud their work :)

I just don't get the downvoting nature of some of the folks here. This isn't reddit.

Downvoting likely signals disagreement as well as disapproval.

But consider this: there may be an electrical engineer reading the article right now thinking "damn, apps are hard, building one at home is quite the feat!"

One of the GNU radio guys built an actual passive radar quite some years ago. I could see someone with that background looking at phone app development and scratching their head ;-)

In the aviation industry the secondary surveillance radar (SSR), as it's called, passively interrogates transmitting air traffic in ATC's airspace (1090 MHz ADS-B and 978 MHz UAT). It's not the primary radar, which is active radar and what most people think of when they hear radar. It's a terminology issue which we're stuck with now given that SSR is part of the nomenclature.

The SSR receiver is usually a long conic rotating dish, the length provides lateral isolation, as the dish itself is tilted up to match the runway glideslope (inbound and outbound track for most transmitting aircraft).

The SSR can receive information well beyond the range of the primary radar. For an air traffic controller, a commercial aircraft shows up on the SSR first, and can be directed right away. The primary radar mainly catches anomalous behaviour, foreign objects and GA aircraft that may not be equipped with UAT.

Ehh, secondary radar is still radar. Swapping the passive reflector for a preamble/header triggered gated (after header received, active for some short duration) non-passive echo, doesn't negate the way of "send radio wave, receive echo, measure latency/delay, divide by twice light speed, get distance".

FYI, discussion on part 1 here - https://news.ycombinator.com/item?id=38435908

Doing God's work!

I did think the same too as radars (active or passive) are indeed complicated, but a quick view to the article clearly it’s just a wrapper around an API, still cool and I downloaded it!

You are taking this too seriously and the answer can be found in the blog post.

It's clearly a dad-daughter fun project and the toddler is more likely calling it a "Radar" and not "Can I play with the ADS-B API Wrapper?" which is the spirit of the whole post and app.

Here are my thoughts I left as a comment on the blog:

I've got ideas! As a parent of a toddler myself, I felt that comment about picking the color... For sure the most important.

Anyways, here is a feature list of things you may have considered but haven't implemented because this is just a fun side project!

1. Live view. Use the phone's camera and iPhone's AR capability to display a dot in the (general) area of the aircraft. I've done some coding on how to calculate this based on the user's position and ADSB info if you are interested!

2. Mark an aircraft as "seen" or "missed"* which would go into the next suggestion.... (*could even digest this feedback in somehow and fine tune what is displayed?)

3. Badges/Stats! If your daughter is anything like mine, she loves getting badges in apps. Maybe create a local DB of previous sightings so then you can track things like "number of different airlines", "number of different aircraft types", "farthest flight time spotted", "shortest flight time spotted" etc etc (Note: I understand and totally appreciate the possible issues around gamifying apps meant for consumption by children.)

If your daughter is anything like mine, she loves getting badges in apps

This may sound curmudgeonly, but I try to drill into my son's awareness that he should aspire to be a producer of technology, rather than just a consumer. We face regular discussions about why he shouldn't spend $30 on Robux or some other digital currency. I try and explain that these digital currencies don't have real value like, say, a tennis racket or a pair of shoes.

As such I also try and give him the tools to fight against gamification, and not to be sucked into grinding for hours to get some badge or other worthless digital artifact.

So my 2 cents would be not to add features like this to an app aimed at kids. Let them see that there is a such a thing as a non-gamified, non-ad infested app that adds real value to their lives.

We face regular discussions about why he shouldn't spend $30 on Robux or some other digital currency. I try and explain that these digital currencies don't have real value like, say, a tennis racket or a pair of shoes.

I’m not sure I agree. Value is a deep and multi-faceted concept. It’s very likely that your child would value the games they can purchase with Robux(it’s my understanding that Roblox has a bunch of games that can be purchased?).

I'm leaning towards what you say even more for the next generation. Assuming our society doesn't fall apart... it seems safe to assume that digital purchases/assets will be an increasing portion of our economy going forward. Teaching children the relative value of those assets (albeit non-transferable) and what that means isn't something that shouldn't be ignored.

It’s all cheeseburgers.

Do you want X or do you want five cheeseburgers?

$15 on Stardew Valley or three Big Macs?

Decide!

They'll eat the Big Macs and start begging for Stardew Valley before you've even had the chance to throw away the boxes.

And therein lies the lesson

Devil’s advocate: is it possible that Robux teach children to contribute financially to the ecosystem’s they participate in? FOSS is famously not “free-as-in-beer” yet we have created the expectation that virtual goods including software do not have financial value. Could being raised on Robux create an incentive to make modest financial contributions to software projects?

Yeah, that is why I included the note at the end. It is an important lesson for adults to teach children right now. I'm also working on teaching my daughter this lesson while we design/create our own "game" for fun on the weekends.

The idea of the badges is to teach things to deepen a child's understanding of planes (planes fly all around the world! At all heights! They are many different sizes!) instead of driving "Average Active Time Spent In The App To Get Special Widgets To Spend In The Radar Flight Store."

Really appreciate the ideas!

Wondering if I can get my hands on a vision pro for #1 :)

Oh man, great idea!

On a sidenote, do kids get invited into the cockpit anymore, in this post 9/11 world?

My Dad was a pilot, and we'd often align a family vacation with one of his flights. There was no prouder moment as a young kid than being invited into the cockpit to "start the engines" after push-back. I vaguely remember pushing some button and Dad pointing out a moving dial in the cockpit. I vividly remember walking back to my seat feeling like the biggest kid in the world.

That kind of thing definitely wouldn't happen post 9/11.

I was on a flight last Thursday and saw this happen.

My 6-year old was invited into the cockpit for the first time on January 1, 2024. I was wondering the same as you up until that moment.

JetBlue US Domestic

My kids have been in the cockpit post 9/11. But you have to do it before takeoff. They don't let anyone in there during flight, even the flight attendants (except the lead sometimes).

My kids just ask as we are boarding the plane if the cockpit door is still open.

It was before we took off :)

Some tip that I read on the internet if your child wants to have a look into the cockpit: don't ask before the take-off because at that time the pilots will have a lot of things to do (doing checklists, preparations, ...). On the other hand, after the landing asking to let your child see the cockpit will have a much higher chance of being successful.

I've seen it happen while the plane is at the gate. The pilots usually have the door open, and you can go up and talk to them. Worst case they say no, so its worth an ask.

Somewhere I still have a Delta wing pin from a trip I took as a kid and got to see the cockpit en route. Very cool experience that I remember to this day — I hope your and others' kids get to experience some piece of it themselves!

This is cute and touching. I'm jealous. I miss it when my daughters were this age. Awesome work dad.

Thank you :) I suppose the grass is always greener, right? I'm simultaneously at the (irrational) age where I'm missing the baby stage and excited for her to learn to play video games with me

You'll never stop missing the baby stage.

The entire period from 3 months to around 5-6 is magical - they are seeing new things, trying new things, learning at a voracious rate, and constantly surprising you. They are still great after that but they are more on their path to who they will become, and mom and dad of course become a little less cool.

Mine are grown and are wonderful people, but I can't tell you what I would give to go back and spend a day at the park with them at 3-4 years old.

Your mileage may vary. I don’t miss this age at all, at 3-6 months a baby is not much more than a moving blob. I enjoy it now way more at the age of three.

I have the benefit/drawback of hindsight from years later. Before 3ish months, I'm with you - it's the "fourth trimester." May depend on the kid too. Mine were relatively calm and quiet, but there were some <1y babies that I met who appeared to scream and cry every waking moment.

We had one of the screaming ones. There was no sleep the four first months until we got the advice to try to give extra milk, maybe she wasn't getting enough food from breast feeding. Her skin started going all bumpy red/white everywhere the babyformula touched and the lips swelled up. Turns out she was milk protein allergic. After clearing out all possible sources of milk protein (Tip: It's in everything, even the things you would never imagine containing milk) her skin returned to normal and she was not screaming the whole time any more.

We had, on advice from a nurse, tried to rule out milk protein earlier by mother not drinking any milk. She did however not say that you have to do that for a very long time before you can see any results. Think it was at least three-four weeks until you could say if it worked or not.

Luckily the milk protein allergy grows away before 7 years old and she is perfectly fine with milk now.

Wow, that's rough. Glad she (and you) got through it. The whole parenthood process teaches humility, that's for sure.

cue the grandchildren

Who here in the HN crowd would be up for porting this to Android as a sort of open-source crowdsource project? Any takers? At a guess (about licensing) I would say that whoever sets up the initial GH repo uses this quote from the author " waiting for an enterprising Android engineer to port it themselves—I’ve placed enough detail in these posts! You’re welcome to do so, just make it free for everybody."

Thanks for the suggestion to do something like this! I've never made a mobile app but would love to learn how. Even if it's not to contribute to a high quality Android app for this radar thing, choosing to spend some of my time porting anything like it which also falls into the "An app can be a home-cooked meal"[0] paradigm likely means that grokking the code will be easier than with because it will be programmed with a singular vision/paradigm and lack bloat/adware/tracking/etc which would complicate reading and understanding the existing code.

This suggestion may put me on the road to find some renewed joy in programming.

0: https://news.ycombinator.com/item?id=38877423

Honestly I was hoping to inspire something like this; where someone wants to learn to build something interesting that isn't just another todo app tutorial

If you do want to build it, I'm happy to share the iOS source with you!

Sure thing, thank you! And totally happy if other efforts either beat me to it and/or create a much more professional port than my own.

reaperman_hn@protonmail.com

I actually started trying to port it to Android after your first post. Only managed to get a compass prototype working though... might revisit the project soon!

[0] https://git.pixelfy.nl/koen_hendriks/airvoyager

I too have a toddler, so I don't have a lot of time, but I am motivated to help. tbelaire on GitHub, but I have only done a little android before.

Good man!

No long-term capacity to maintain it, but I can probably contribute a little.

email in my profile

Slightly off-topic but a question I've been wanting to ask: as someone with a terrible sense of direction, the most important feature in a phone for me is the accuracy of the little arrow on the map that shows me which way I'm facing. I'm an android user, and it kind of shows a blue "cone of uncertainty" when it isn't sure which way its pointing, and occasionally asks either to move the phone in a figure of eight or to point at nearby building to calibrate.

What is the limiting factor here, technologically? Are iPhones better than android? Is it the hardware (accelerometer?!, compass?), the GPS signal, the software? It still, quite often, seems to get confused and show the cone in the wrong direction. It's so important to me that I would almost switch to iPhone if it definitely works better.

Glad you said this - I actually made the same observation in the original post!

I assumed maybe there was some kind of GPS limiting factor, but the CoreLocation orientation delegate perfectly returns your orientation, at least at my device's 120Hz frame rate.

I think Google Maps might just be bad.

I think it could be about hiding the level of accuracy. I remember sometime back learning that there are many cases where sounds are added back for comfort and the expected experience that customers are used to, so perhaps this is one of those cases where they have continued as a company to mask their true power and just like with everything they do, they cannot appear to be a monopoly so they need to fake the accuracy defects and all that while behind the scene they are actually tracking it all ..... who knows.

I'm an android user, and it kind of shows a blue "cone of uncertainty" when it isn't sure which way its pointing, and occasionally asks either to move the phone in a figure of eight or to point at nearby building to calibrate.

Apple products and animations generally have more smoothing and hysteresis; my presumption is that the accuracy is hidden from the user in an effort to make sure that the arrow doesn't fluctuate wildly, whereas the android UI is more likely to show artifacts from the 'noisy' GPS/IMU fusion and inherent magnetometer inaccuracies.

'Slow arrow' was one of the things that kind of drove me crazy in iOS back in the old days now with faster hardware I notice the 'twitchy' arrow more on other platforms.

tl;dr: Most modern hardware is pretty equal as far as being able to determine its' place in space and time with decent accuracy now , but not all navi software is equal in terms of dead reckoning accuracy and pose estimation given the current data and the user expectation of noise filtering while handling the phone.

As someone using both equally often, I am kind of certain Android passes through the raw sensor readings while iOS has some form of debounce delay and guesstimation implemented. Both are equally often off in their readings. But that's just based on usage experience, not a hard fact.

One thing that I'm noticing with the app is something I experienced from my days of DVD programming. It is not clear which mode is currently active with the toggle buttons. It is not obvious if the flag is showing you the current mode or if the button needs to be pressed to get the indicated mode. To toggle the weather, do you click the clouds to show cloudy mode or to view clear view or vice versa. It almost feels inverted to me.

I'm also having the same issue on a current project. There's a set of +/- buttons that control the size of a time range window. Clicking the +/- buttons increase/decrease the size of the window, but for the start time + makes the time seconds value smaller, and - makes the seconds value larger. For the end value, it is exactly the opposite. But for the window size, both sets of buttons do what one expects. So it's a matter of perspective that needs to be clear to the user.

This is what I hate most about modern UX-- especially on TV apps. A menu with two items: one is bold white and the other is bold black. What am I about to click?

The youtube captions toggle is guilty of this too. It toggles between black on white and white on black. I just have to click it and wait until I see someone's lips moving with no captions then try the other icon mode.

It's like the move to touchscreen erased everyone's common sense for stateful positional input feedback.

Not sure about common sense and touch screen as it's been around for much much longer. It's also something easily not considered when one is not trained in the ways of the UI. However, it is something that is easy to understand once it is pointed out to you and you are the one under the microscope for it.

For example, in this specific app, the flag/no flag is easier to discern its use compared to the cloud/sun icon. It doesn't follow the same logic as the flag/no flag. It could be cloudy/not cloudy cloud or sunny/not sunny, and then it follows the flag. Consistency between buttons is important

YouTube captions toggle

While I've seen similar problems the captions toggle hasn't been one of these for me. On desktop it uses a red underline when activated which is very clear that it's currently activated. On other platforms, I've seen the button's background toggle between translucent button with outlined icon to white button with filled icon, which I find intuitive but I guess others might not.

This is a very fair point. I think I got hung up a little on making it look like a control panel rather than making the UX good.

And you certainly aren't going crazy either, I shipped a last-minute bug-fix where I got the cloud icon the wrong way around compared to everything else

Awesome!

Side note, I'm tempted to place a !remindme in 18 years to check if your daughter managed to pass her flight control exams ;)

Do we get free flights if our daughter is a pilot? Maybe we're missing a trick nudging her into STEM

there's a whole buddy pass system for friends/family of airline crew. short answer: yes, but.

She’s 2 and can get a student pilot license at 16 so set a reminder in 14 years.

I tried to run that app like 5 times since it was released and it failed to connect to the server every single time.

Really sorry about this, are you rural by any chance? I believe there is an error message if there is nothing found overhead; as a Londoner I don't think I properly prepared for the less crowded airspaces!

I’ve had the same issue in rural Canada. Installed a few times and thought it was high traffic from HN causing issue, but that makes more sense as there’s probably only a plane overhead for me twice a day!

Thanks for confirming! Sounds like my error handling logic needs work.

I built it from London so the sky-area I calibrated it for might be really small for someone in the rural Americas

This looks really cool and has a wonderful story behind it. But I’d have to get a new phone to try it, as my OG iPhone SE only supports up to iOS 15, and the App Store says this requires iOS 17…

My apologies, unfortunately this was only possible in SwiftUI with some of the new features (which I naturally wanted to try out!)

I’m sorry if it came across as a complaint. It’s just the consequence of me sticking with this 8 year old phone. I’m a bit sad I can’t try your awesome looking project, but it’s because of my own stubbornness :-)

I am the co-founder of Planefinder.net. We’ve been tracking aircraft since 2009.

Good work!

Love it!

Game recognise game ;)

My house is below a rural MOA airspace and occasionally gets buzzed by extremely low flying military aircraft. It can be window rattling, ground shaking and heart rate elevating. Do you know of a way I can get an alert even a little bit before that happens? Is it theoretically build-able with existing data?

Nice one. I'm glad you're still pleasing your user base.

Well, I am back to pleasing them after a brief 5-week production incident :)

for the rest of his days probably

Maybe nice if the toddler can see on the radar where daddy is too.

Why is this downvoted? I thought it was a nice idea.

I think the downvoters read it as a snide comment that I should spend more time parenting and less time on side projects

That's a neat idea though, I'm picturing some kinda hyperlocal room-level location tracking!

There can be a temptation as a parent to practice our hobby in a way that makes us feel that we are engaging with our child when actually our child would be just fine with FlightRadar and more of daddy.

I'm not judging (really) because every family has different circumstances and every person is different, I just know that I jumped into this trap a few times and you are reminding me of myself back then.

Brain Rules for Baby is an excellent way to learn how your child works, or at least I found to be so.

Anyway, you're nearly at Brio and then Lego and it gets better and better...

Very nice, even with no planes overhead. But it looks like the map orientation is reversed (off by 180 degrees)? Real bug, or just me?

What hemisphere are you in by any chance? I am not an expert on geolocation theory so I may just not know how MapKit works :)

Also, are you looking at your phone screen up from above, or screen down from below with the sky behind it?

Would the correct orientation be rotated of mirrored?

Congrats and thanks for updating! Both of my kids are avid users.

Glad to hear it! :)

Does it blip planes when the radar scan rolls over them and they stay in a static position but fade until the next sweep? That would be so cool.

Would also be amazing to look at device current gps altitude and location to determine the visible skyline per azimuth based on openstreetmap buildings and hills/elevation around your current position and altitude... then you can show it on the map as a radar occlusion [1] - like a fish finder when you go over a log, or ship radar occluded by another vessel.

I'm sure you'd cause some industry people to scratch their head and wonder how the phone is doing radial scanning

[1] https://www.researchgate.net/figure/Occlusion-percentage-for...

I love all these ideas - my app is very much the Pareto version of the potential 100% complete version

As always, it’s uniquely gratifying to create something my daughter wants to play with. I look forward to her developing many more interests — with any luck, soon she’ll get super into platforming games or heavy metal.

I got into heavy metal because of the Tony Hawk games (THPS3 - Motorhead's "Ace of Spades", THPS4 - Iron Maiden's "Number of the Beast"). So there's a potential breadcrumb trail.

I appreciate your wisdom

As another father of a plane loving toddler, one of her favourite questions is "where's it going?". I'm wondering if some flight information is available and could be shown by selecting the plane.

As an adult who often wonders this, RadarBox's AR mode (available on the iPhone app) is perfect. You just point it in the general direction of the plane, tap on the flight number, and it will show you all the details.

Alternatively you can just look at the web version and guess which one you're seeing. https://www.radarbox.com/

Neat, my 2-year old is also excited about planes and this is exactly the of application I had envisioned.

Their feedback is welcome!

This is a follow-up to a rather popular post from a couple months ago[0].

0: https://news.ycombinator.com/item?id=38435908 My toddler loves planes, so I built her a radar (1304 points, 56 days ago)

Aw, shucks :)

Good job on definitely making your most important user happy :)

Anyone working on an Android port yet? I might try my hand at a React Native port as a learning experience. Or is Flutter better?

there's some discussion upthread, a couple of hours before your post

First app I see in the wild that only supports iOS 17. Maybe I will upgrade some day.

This is actually the first OS where this app is possible to build in SwiftUI - the MapKit annotations and Metal shaders are both brand new

"One would think, as an enterprising indie developer, I’d jump straight on top of the hype train, shoot out another release, and begin dreaming up monetisation opportunities."

My (now) 12 year old and me are working on a little game for a while. It started as a purely educational project, but I think it turned out good enough to be published.

I don't want to commercialize it for multiple reasons, but I'm curious how this will go on the App Store. There are few truly and completely free apps so this is kind of uncharted territory. Since Apple does not earn anything from free apps, I can imagine they are not very keen on having them in the store.

I am very curious to hear what experiences others had with publishing free apps. Was it hard to get them approved? Were they pulled from the store?

Of course the toddler is who loves them, haha