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Last summer, I was inspired by a computer that was built inside of a toaster that I saw at a local computer recycling store. The idea of a computer with the design of a home appliance was really appealing and so was the absurdity of it. It occurred to me that this would be a fun and creative way to integrate technology into my life. After thinking about it, I realized there’s also something visually appealing about how simple and utilitarian toasters are. I have major nostalgia for the famous After Dark screensaver and I think this is why. I knew now that I wanted to make my own attempt at a toaster/computer hybrid. I decided to do just that when I created the DataToaster 3000: a toaster NAS with two 3.5 inch hard disk docking stations built inside it. The hard disks can be easily swapped out (while powered off) without taking anything apart. It uses a Zimaboard x86-64 single board computer and even has a functional knob that controls the color of the power LED. I designed a fairly complex set of 3D-printed parts that attach to the base of the toaster and hold everything neatly in place. This allows it to be easily disassembled if I ever want to make any modifications and also hopefully makes the project easier to build for others. It’s a ridiculous thing but I really do love it. You can find the build guide on Instructables and the 3D models on Printables.
I wanted to add more hauling capacity to my bike and was looking for something compatible with my Yepp rear rack. I also use my rack with a child seat (the Yepp Maxi) which has a mechanism that allows it to attach and detach easily without sacrificing safety. I was thinking it would be great to build a Yepp compatible rear basket that could I just as quickly attach/detach from my rack. I designed a removable Yepp-rack-compatible rear basket that consists of a milk crate, some plywood for stability and a 3D printed bracket threaded for M6 bolts which hold it all together. It can be attached and removed in seconds and is very secure. 3D Printed Mounting Bracket I modeled my mounting bracket after the one on the Yepp Maxi childseat. After a few iterations I was able to make it perfectly fit. I printed it in PETG filament so it was UV resistant and then installed threaded inserts for M6 bolts to attach it to the milk crate and my rear rack. 3D Print and Build Instructions You can find the 3D print on Printables and a full build guide on Instructables.
The Yoto Mini is one of my favorite products. The team behind it deeply understands its users and put just the right set of features into a brilliantly designed package. I have no affiliation with Yoto, I’m just a happy customer with kids who love it. If you aren’t aware, Yoto is an audio platform for kids with what they call “screen-free” audio players (even though they have little pixel LED screens on them). The players are Wi-Fi enabled and support playing audio from credit card-sized NFC tags called Yoto cards. Yoto sells audio players and also licenses audio content and offers it on its platform as well. The cards themselves do not contain any audio data, just a unique ID of the audio content that is pulled from the cloud. After content is pulled on the first play, it is saved and played locally from the player after that. Yoto also supports playing podcasts and music stations without using cards. Their marketing puts a lot of emphasis on the platform being “ad-free” which is mostly true as there are never ads on Yoto cards or official Yoto podcasts. However, some of the other podcasts do advertise their content. So, what’s so great about the Yoto Mini? This concept isn’t new as there have been many examples of audio players for kids over the years. What sets it apart is how every detail of the hardware, mobile app, and exclusive content is meticulously designed and well executed. Yoto Mini Hardware The main input methods of the Yoto Mini are two orange knobs, turning the left knob controls volume and the right knob navigates chapters or tracks. Pressing the right knob instantly plays the Yoto Daily podcast and pressing it twice plays Yoto Radio (a kid-friendly music station). These actions are both configurable in the mobile app. The NFC reader slot accepts Yoto cards and instantly starts playing where you left off after you insert one. It has a high-quality speaker that can be surprisingly loud, an on/off button, a USB-C charging port, an audio output jack, and a small pixel display that shows images related to the audio content. The Yoto Mini is also surprisingly durable. My kids have dropped it many times on hard surfaces and it still basically looks as good as new. Yoto understands that the physical audio player itself is primarily used by younger kids and the design reflects this. My 3-year-old daughter was able to figure out how to turn it on/off, start listening to books using cards, and play the Yoto Daily podcast each morning which was empowering for her. This was her first technology product that she was fully capable of using without help from an adult. I can’t think of many other products that do this better. Yoto Mobile App The Yoto team understands that parents are users of this product too, mostly for managing the device and its content. Yoto has built a very good mobile experience that is tightly integrated with the hardware and provides all the features you’d want as a parent. From the app, you can start playing any of the content from cards you own on the player or your phone (nice if your kids lose a card), you can set volume limits for both night and day time, you can set alarms, and configure the shortcut buttons. You can record audio onto a blank Yoto card (which comes with the player) if your kid wants to create their own story, link it to their favorite podcast or favorite music. The app even lets you give each track custom pixel art that is displayed on the screen. Audio Content By far the most underrated feature is a daily podcast called Yoto Daily. This ad-free podcast is run by a charming British host and it is funny, entertaining, and educational. My kids (now 4 and 7) look forward to it every morning and the fact that it’s daily free content that is integrated directly into the Yoto hardware is amazing. To me, this is the killer feature, as my kids get to enjoy it every day and it’s always fresh and interesting. Yoto licenses content from child book authors, popular kid’s shows, movies, and music (recently the Beatles) which are made available in their store. I also discovered that Yoto does not seem to lock down its content with DRM. My son traded some Yoto cards with a friend and I assumed there would be some kind of transfer or de-registration process but to my surprise, they just worked without issue. Conclusion The Yoto Mini is a delightful product. The team behind it thought through every detail and made it an absolute joy to use both as a child and parent. I’m impressed at how well the Yoto team understands their users and prioritizes simplicity and ease of use above all else.
When I first got my 3D printer, I built an enclosure to protect it from dust, maintain a consistent temperature, and minimize noise. I was surprised to find that the enclosure didn’t reduce noise that significantly. I then placed a patio paver under my printer, which made it noticeably quieter, but it was still audible from other rooms in my house. Recently, I found the most effective noise reduction solution: squash balls. These balls are designed with varying bounce levels, indicated by colored dots. The “double-yellow dot” balls have a very low bounce, making them ideal for dampening vibration, which is the primary cause of printer noise. I found an existing design for squash ball feet, printed it, and hot glued them evenly under my patio paver. My current setup includes the enclosure, patio paver, and squash balls under the paver. Now, the printer is so quiet that I actually can’t tell if it’s running, even when I’m in the same room. Occasionally, I will hear the stepper motors, but that’s rare. Most of the time I need to open the enclosure to make sure it’s still printing.
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The world changed a lot in 1995. And for the web, it was a transformational year. The post 1995 Was the Most Important Year for the Web appeared first on The History of the Web.
I have a lot in the works for the this month's Logic for Programmers release. Among other things, I'm completely rewriting the chapter on Logic Programming Languages. I originally showcased the paradigm with puzzle solvers, like eight queens or four-coloring. Lots of other demos do this too! It takes creativity and insight for humans to solve them, so a program doing it feels magical. But I'm trying to write a book about practical techniques and I want everything I talk about to be useful. So in v0.9 I'll be replacing these examples with a couple of new programs that might get people thinking that Prolog could help them in their day-to-day work. On the other hand, for a newsletter, showcasing a puzzle solver is pretty cool. And recently I stumbled into this post by my friend Pablo Meier, where he solves a videogame puzzle with Prolog:1 Summary for the text-only readers: We have a test with 10 true/false questions (denoted a/b) and four student attempts. Given the scores of the first three students, we have to figure out the fourth student's score. bbababbabb = 7 baaababaaa = 5 baaabbbaba = 3 bbaaabbaaa = ??? You can see Pablo's solution here, and try it in SWI-prolog here. Pretty cool! But after way too long studying Prolog just to write this dang book chapter, I wanted to see if I could do it more elegantly than him. Code and puzzle spoilers to follow. (Normally here's where I'd link to a gentler introduction I wrote but I think this is my first time writing about Prolog online? Uh here's a Picat intro instead) The Program You can try this all online at SWISH or just jump to my final version here. :- use_module(library(dif)). % Sound inequality :- use_module(library(clpfd)). % Finite domain constraints First some imports. dif lets us write dif(A, B), which is true if A and B are not equal. clpfd lets us write A #= B + 1 to say "A is 1 more than B".2 We'll say both the student submission and the key will be lists, where each value is a or b. In Prolog, lowercase identifiers are atoms (like symbols in other languages) and identifiers that start with a capital are variables. Prolog finds values for variables that match equations (unification). The pattern matching is real real good. % ?- means query ?- L = [a,B,c], [Y|X] = [1,2|L], B + 1 #= 7. B = 6, L = [a, 6, c], X = [2, a, 6, c], Y = 1 Next, we define score/33 recursively. % The student's test score % score(student answers, answer key, score) score([], [], 0). score([A|As], [A|Ks], N) :- N #= M + 1, score(As, Ks, M). score([A|As], [K|Ks], N) :- dif(A, K), score(As, Ks, N). First key is the student's answers, second is the answer key, third is the final score. The base case is the empty test, which has score 0. Otherwise, we take the head values of each list and compare them. If they're the same, we add one to the score, otherwise we keep the same score. Notice we couldn't write if x then y else z, we instead used pattern matching to effectively express (x && y) || (!x && z). Prolog does have a conditional operator, but it prevents backtracking so what's the point??? A quick break about bidirectionality One of the coolest things about Prolog: all purely logical predicates are bidirectional. We can use score to check if our expected score is correct: ?- score([a, b, b], [b, b, b], 2). true But we can also give it answers and a key and ask it for the score: ?- score([a, b, b], [b, b, b], X). X = 2 Or we could give it a key and a score and ask "what test answers would have this score?" ?- score(X, [b, b, b], 2). X = [b, b, _A], dif(_A,b) X = [b, _A, b], dif(_A,b) X = [_A, b, b], dif(_A,b) The different value is written _A because we never told Prolog that the array can only contain a and b. We'll fix this later. Okay back to the program Now that we have a way of computing scores, we want to find a possible answer key that matches all of our observations, ie gives everybody the correct scores. key(Key) :- % Figure it out score([b, b, a, b, a, b, b, a, b, b], Key, 7), score([b, a, a, a, b, a, b, a, a, a], Key, 5), score([b, a, a, a, b, b, b, a, b, a], Key, 3). So far we haven't explicitly said that the Key length matches the student answer lengths. This is implicitly verified by score (both lists need to be empty at the same time) but it's a good idea to explicitly add length(Key, 10) as a clause of key/1. We should also explicitly say that every element of Key is either a or b.4 Now we could write a second predicate saying Key had the right 'type': keytype([]). keytype([K|Ks]) :- member(K, [a, b]), keytype(Ks). But "generating lists that match a constraint" is a thing that comes up often enough that we don't want to write a separate predicate for each constraint! So after some digging, I found a more elegant solution: maplist. Let L=[l1, l2]. Then maplist(p, L) is equivalent to the clause p(l1), p(l2). It also accepts partial predicates: maplist(p(x), L) is equivalent to p(x, l1), p(x, l2). So we could write5 contains(L, X) :- member(X, L). key(Key) :- length(Key, 10), maplist(contains([a,b]), L), % the score stuff Now, let's query for the Key: ?- key(Key) Key = [a, b, a, b, a, a, b, a, a, b] Key = [b, b, a, b, a, a, a, a, a, b] Key = [b, b, a, b, a, a, b, b, a, b] Key = [b, b, b, b, a, a, b, a, a, b] So there are actually four different keys that all explain our data. Does this mean the puzzle is broken and has multiple different answers? Nope The puzzle wasn't to find out what the answer key was, the point was to find the fourth student's score. And if we query for it, we see all four solutions give him the same score: ?- key(Key), score([b, b, a, a, a, b, b, a, a, a], Key, X). X = 6 X = 6 X = 6 X = 6 Huh! I really like it when puzzles look like they're broken, but every "alternate" solution still gives the same puzzle answer. Total program length: 15 lines of code, compared to the original's 80 lines. Suck it, Pablo. (Incidentally, you can get all of the answer at once by writing findall(X, (key(Key), score($answer-array, Key, X)), L).) I still don't like puzzles for teaching The actual examples I'm using in the book are "analyzing a version control commit graph" and "planning a sequence of infrastructure changes", which are somewhat more likely to occur at work than needing to solve a puzzle. You'll see them in the next release! I found it because he wrote Gamer Games for Lite Gamers as a response to my Gamer Games for Non-Gamers. ↩ These are better versions of the core Prolog expressions \+ (A = B) and A is B + 1, because they can defer unification. ↩ Prolog-descendants have a convention of writing the arity of the function after its name, so score/3 means "score has three parameters". I think they do this because you can overload predicates with multiple different arities. Also Joe Armstrong used Prolog for prototyping, so Erlang and Elixir follow the same convention. ↩ It still gets the right answers without this type restriction, but I had no idea it did until I checked for myself. Probably better not to rely on this! ↩ We could make this even more compact by using a lambda function. First import module yall, then write maplist([X]>>member(X, [a,b]), Key). But (1) it's not a shorter program because you replace the extra definition with an extra module import, and (2) yall is SWI-Prolog specific and not an ISO-standard prolog module. Using contains is more portable. ↩
Startup CEOs should ask themselves what crazy ideas can turn into a move that just ends a market's competitive dynamic
We just opened a search for a new junior programmer at 37signals. It's been years since we last hired a junior, but the real reason the listing is turning heads is because we're open about the yearly salary: $145,849*. That's high enough that programmers with lots of experience are asking whether they could apply, even if they aren't technically "junior". The answer is no. The reason we're willing to pay a junior more than most is because we're looking for a junior who's better than most. Not better in "what do they already know", but in "how far could they go". We're hiring for peak promise — and such promise only remains until it's revealed. Maybe it sounds a little harsh, but a programmer who's been working professionally for five years has likely already revealed their potential. What you're going to get is roughly what you see. That doesn't mean that people can't get better after that, but it means that the trajectory by which they improve has already been plotted. Whereas a programmer who's either straight out of school or fresh off their first internship or short-stint job is essentially all potential. So you draw their line on the basis of just a few early dots, but the line can be steep. It's not that different from something like the NFL scouting combine. Teams fight to find the promise of The Next All-Star. These rookies won't have the experience that someone who's already played in the league for years would have, but they have the potential to be the best. Someone who's already played for several seasons will have shown what they have and be weighed accordingly. This is not easy to do! Plenty of rookies, in sports and programming, may show some early potential, then fail to elevate their game to where the buyer is betting it could be. But that's the chance you take to land someone extraordinary. So if you know a junior programmer with less than three years of industry experience who is sparkling with potential, do let them know of our listing. And if you know someone awesome who's already a senior programmer, we also have an opening for them. *It's a funnily precise number because it's pulled directly from the Radford salary database, which we query for the top 10% of San Francisco salaries for junior programmers.
Data engineering is a field I would categorize as a subspecialty of software engineering. It shares the same concerns as software engineering—scalability, maintainability, and other “-ilities”—but its primary focus is on data. It’s a unique discipline because data is inherently messy, and as a result, no standard enterprise framework has emerged to dominate the space—and […]
