I was on the front page of Hacker News for about five minutes before being booted (still learning the ropes on how HN posting works), so I guess it wasn’t a big hit. I was even in touch with the kind folks over at Pusher who bumped me up to a higher number of allowed simultaneous connections to prepare for HN traffic, but alas I never needed it. Thanks anyway Pusherinos!
What it boiled down to was that the loop inside of the pulseIR() function stipulates in the comments that “38 kHz is about 13 microseconds high and 13 microseconds low”, and after experimenting with some timings I realized that the calls to `digitalWrite()` were taking longer than the proposed “3 microseconds”. I lowered the value of `hangoutTime` from 10 down to 7 and voila, it works! It was as simple as that one change! I modified the gist accordingly, and now I’m in business!
So I was leaving work today when something interesting happened… I got in the elevator, and there was a girl in there. She anxiously checked her phone while we waited for the elevator to descend. Another guy got in before we got there, and the three of us waited for that door to open at the ground floor. When it did, the guy walked to the right, to the north exit of the building. I then did the gentlemanly thing to do and let the girl exit the elevator ahead of me. She walked to the left, to the south exit of the building, where I was also going. We went through both sets of doors, and she turned to the right to walk west down the street, the same direction I was planning on going. Maybe I’m paranoid, but after about a half of a block I noticed that she stopped, paused, looked around, and allowed me to pass, and in my paranoid mind this is because she got the feeling that I was following her.
Now this isn’t the first time that this has happened (not the same girl other times), and I’m sure it won’t be the last, so I started thinking about this mathematically. My statistics are a bit rusty (maybe someone can remind me what operation would solve this), so I relied on scripting out a brute force solution:
Assuming there are four exits to the building, what is the probability that at least one other person in the elevator with this girl will choose the same exit as her?
Running this a few times, I got these results:
Would you look at that! It seems that with only 3 more people in the elevator, it is actually more likely than not that one of them will go out the same exit as her!
These ladies leaving their work places should stop being paranoid that someone is following them!
(a more likely conclusion: this whole scenario occurred entirely in my head and I am the one who should stop being so paranoid!)
Howdy guys and girls! It’s summertime and it’s hot in New York City. You always hear about those blog posts about people setting up an Arduino to control their air conditioners remotely, and I figured I was due for my own, so here it is. Unfortunately, I was unsuccessful. Hopefully someone can read through what I did and I can follow up with a successful completed post. Either way, here we go…
After some research, I realized that I don’t want to deal with any electronic internals of the air conditioning unit (as I am no electronic engineer, just a computer scientist dressed up as one), so I will be communicating with it by simulating the requests of the remote control with my Arduino via infrared.
Remote-controllable air conditioner (mine is some Zenith model, I don’t think it should matter)
As you can (hopefully) see, I have my Arduino and a breadboard with the IR Receiver plugged into digital pin 2, ground, and 5V. I also have the IR Emitter plugged directly into digital pin 12 and ground. (Side note: do I need any resistors anywhere here? I know about Ohm’s Law, but I’m not sure exactly how to apply it here)