The writing on this one is much nicer! Add selective erase so only one character is (usually) ever erased and you've got yourself a very neat novelty clock.
Not sure if you meant this as a joke (a laser cutter is probably harder to come by than a 3d printer). But back in my day for things like this we simply used a jig saw to cut out parts from wood or plastic. Anything more complex would need several pieces cut out and glued together.
The author says the device is a USB modem. So, under Linux, the author could have simply written a udev rule to use the name "whiteboard" for that particular USB modem's device file.
Let's say someone wanted to learn how to do this. Not just follow a step by step guide, but actually learn how to do this. Where would you find a good resource?
You would need to control a pair of servos. Arduino is the easy way. Some trigonometry to convert x-y positions to the two arm angles. The connectors to the pen are linkages.
I am currently building a whiteboard plotter myself, though a much larger scale.
Feel free to send me questions and I can send you pointers on where to research next.
There are three parts to learn -- the electronics (handled by an Arduino and a few servos), the mechanics (for this design, it's not too complicated -- you could make do with popsicle sticks and some screws if you had to), and the software. The tricky bit with the software is the math. The arms, when free to spin around their centers, can be considered circles. You'd want to learn the geometry of circles and, specifically, how to find the intersection of two circles. The joints on the arms are where the circles meet.
I'm working a new version of my mobile testing robot that looks very similar to this clock. Haven't posted the code, yet, but I did have to go back and re-learn some trig and circle geometry to make the simulator. http://youtu.be/qRzrm4zx82g
A good starting point might be to use Lego + Mindstorm (or Lego + Arduino). You get to use various off the shelf mechanical parts and you get to re-use the Lego parts in your next project.
Yup, that's a fine suggestion, too. I used to do all my prototyping with Lego Technic pieces... Years later, when I needed parts that Lego didn't make (like for connecting servos or Arduino), I used Lego dimensions to create my own 3D printable (but Lego compatible) parts.
You could probably build a similar thing almost out of the box (BYO marker and whiteboard) and you can replace the various parts with your own bits as you get more advanced.
I suppose if you knew what you were doing going an Arduino is a cheaper option though.
This of course depends on what you know already (CS or EE background?), but the easiest way would be to use an arduino. You'd need to have some electronics knowledge (basic circuitry, servo motors) and be able to do some embedded programming (PWM, ADC/DAC, interrupts/timers)
Using a home presence API (like Nest's), this thing could also abstain from updating the time until you were home or in the same room as it. That could dramatically reduce wear and tear.
A cool next step (especially for classrooms) would be giving the robot "eyes" and letting it get the time from a physical clock in the room via image recognition.
Could eventually be extended to scetch outlines of objects/people :D
It's a bit disappointing that they went to the trouble of building a radio into it and didn't just connect it to the NIST atomic clock radio time signal WWVB.
Sorry for asking this stupid question, but what program is that waveform screenshot from? I've been looking for a GTKWave alternative for some time now …
https://news.ycombinator.com/newswelcome.html
"The worst thing to post or upvote is something that's intensely but shallowly interesting: gossip about famous people, funny or cute pictures or videos, partisan political articles, etc. If you let that sort of thing onto a news site, it will push aside the deeply interesting stuff, which tends to be quieter."
Someone hacked together something and is sharing it. It's exactly what HACKER News is about. Heaven forbid someone do something relevant to the site and share it. Lets get some more X rewritten in y lines of JavaScript posts instead.
It's a very cool/fun project and definitely not a cat video. I do believe that it's relatively "shallowly interesting" and I haven't read any comments yet that would indicate to me otherwise. I take the 550+ up-votes it's gotten as a sign that the value (for me at least) of the hacker news filter is slowly degrading.
Sincere answer:
I look and this and think: how did they do that? Do I know how to do that? Could I do parts of it "better"? Knowing this is possible, are there cooler things I could do with it?
If you're willing to think about it for a little while, there's much beyond shallow interest.
It's hilarious how while it's writing it looks like two small arms cupping the marker. Slap on a smiley-face sticker and you're ready to go to market.