[PHY] A3: Micro-controller basics, the cat pressure plate + ID card observations


I followed the lab instructions posted on the phys comp website. Connecting everything and writing/copying the code wasn’t difficult, but understanding it all was quite a challenge. I doubt I can explain what is happening with the board. I can when I am learning or when I am doing it, but an hour later – I don’t remember anymore. I don’t know why. It is really frustrating. On top of it, I cannot think up of any creative ways to use this button or something else entirely.

Probably an element of this idea that “if a switch is pressed something happens” is used in the wireless charging devices (which are obviously way x infinity more complex). With phones it’s probably something along “if this device whose NFC (?) chip we can sense is on this pad, then we can charge it”.

ID card observations

I observe people everyday going in and out of the 370 Jay Street ITP building. People usually tap their ID cards and expect the doors to let them through. Most of the time it works, and when it doesn’t it’s usually due to the swiftness of the tap or maybe there is something blocking the reader from sensing the ID card.

Some people like to have their ID card hang on their necks and some like me like to keep them in their wallets. I used to use the case for the ID card, but it was too thick for my pockets. When I used it with the case it worked a lot better than now when I use it with my wallet. The difference is tiny and it doesn’t hinder my ability to enter the building.

What I imagine is happening is

  • that there are magnetic strips that designate the ID number for the card
  • the sensor attached to the doors reads the number and checks whether or not it’s in the database.
  • the database is probably in SQL on some server somewhere (but that would make it problematic if there is no connection)
  • …or there is a simple authorize/deauthorize state for that ID code


I can see that the two things I talked about in this blog are kind of related. But I also feel overwhelmed. Yeah I connected the wires and made it turn on, but all the work was done for me. All the thinking as well. When I try to think up of things myself – I hit a mental block. If Newton stood on the shoulders of giants, then I am standing on the shoulders of millions of titans.

I will try and tinker more with Arduino IDE and see where it leads to.

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