How to Set Up a Raspberry Pi on CMU WiFi with SSH Enabled

If you currently have your Pi up and running on a home WiFi network, you can save yourself a lot of time by getting your Pi’s MAC address and registering its information on CMU-DEVICE before you move it to campus. Just type in the command line:

ifconfig eth0

and copy down the string after HWaddr. Then register your device. To get started setting up WiFi and SSH, remove the microSD card from the Pi and mount your microSD card on your computer.

Open Terminal and navigate to the microSD directory. Assuming your card is named boot, you can just type:

$ cd /Volumes/boot

Create the file wpa_supplicant.conf (this will replace the current RPi wifi config on next boot):

$ nano wpa_supplicant.conf

The basic format for the wpa_supplicant.conf is below, but we have to adjust it a fair bit for the CMU-DEVICE network. Take a look at the format then scroll down for the settings we’ll use.

country=CODE
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
       ssid="ssid"
       psk="password"
       key_mgmt=WPA-PSK
    }

We’ll change CODE to the US country code, and the psk, ssid, and key_mgmt variables to match the CMU-Device network.

Paste the following into the file (delete any other text in the file first, if there is any):

country=US
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
       ssid="CMU-DEVICE"
       key_mgmt=NONE
    }

Save this file, close it, and then enable ssh with the following command:

$ touch ssh

Now unmount your microSD card, place it back in your Pi, and on boot your Pi will connect to the specified Carnegie Mellon network with SSH enabled!


How To Embed Google Calendar in Squarespace Without a Premium Plan

  1. From Home, navigate to Pages

  2. Create a new blank page called “Calendar” (I created mine under Not Listed so it only can be found by going tabb.me/calendar)

  3. Click Edit Page Content, then the + and add the “embed” content block to the page.

  4. Click the </> icon beside “Enter an embeddable URL here”

  5. In the text box, paste the below code block, but replace name and mail.com with your email address, leaving the %40 in place of @. Make sure your Google calendar is set to show availability publicly. You can also customize some of the attributes like height and bgcolor.

    <iframe src="https://calendar.google.com/calendar/embed?showTitle=0&amp;showPrint=0&amp;mode=WEEK&amp;height=500&amp;wkst=1&amp;bgcolor=%23FFFFFF&amp;src=name%40mail.com&amp;color=%231B887A&amp;ctz=America%2FNew_York" style="border-width:0" width="100%" height="500px" frameborder="0" scrolling="no"></iframe>

  6. Hit set then apply then save

  7. Hover over the page name “Calendar” on the left side panel and click the gear icon for settings, then adjust the URL slug to “cal” or “calendar”

  8. Take a moment to celebrate; you have a new calendar page 🎉

Some Questions About Signs

I like seeing things, so I keep my eyes open (usually). As a consequence, I let signs into my life. Some signs are very helpful, some are not. While I don’t know what makes a “good” sign and what makes an “evil” sign, I do know that all signs— whether a billboard or a street sign— don’t ask my permission before invading my thoughts and forcing information upon me.

Without consent, a sign tells me things about the world— but what if I don’t want it? Why do I need to know the name of every street, bank, pizza shop, or corner store? Why does a sign have permission to make me think (and sometimes do or not do) things?

What would a world without signs be like? Surely there was a time, maybe before writing appeared, where we did not have signs. And who thought of the idea of a sign in the first place? Abstracting qualities of something physical into short written words or visuals that carry big meaning— that’s so profound! Was it nice to not have signs, or were people always yearning for signs but didn’t have the tools to make them?

Currently, these are my thoughts on signs. I’ll add more thoughts if I have them

4D Spork

A fork has two states. So too does a spoon. but a spork? a spork has three. What does this mean?

Source: The Morphing Matter Lab @ Carnegie Mellon University

Source: The Morphing Matter Lab @ Carnegie Mellon University

Consider sporks are not good spoons, and are even worse forks. Just like a flying car is not a good car and not a good plane. Previous attempts to redefine the spork focus on optimizing the geometry of a fork-spoon union, but what if instead we tried to optimize the spork in a different way.

I think a spoon and fork each has two states: in use and at rest. A spork has three: in use as a spoon, in use as a fork, and at rest. I think the ideal solution should focus in the transition between rest to fork use, and rest to spoon use. As a spork doesn’t usually have to at once be both a spoon and fork, it just has to be either.

A solution is to adapt 4D printing practices to the utensil space. 4D printing is a way of varying parameters during 3D printing so the final print is flat, but when surrounded by a heated environment, the object can gain permanent 3D geometry. The image at the top illustrates some flat geometry, and their heated final 3d shapes.

very simple graphic of the future of sporks

very simple graphic of the future of sporks

Now imagine a flat utensil resembling a fork, but with a rounded body. Like the silhouette of a spoon with the tines of a fork

When used in most fork applications, the object would remain in its original shape, able to function well in a fork-like way!

But, when the utensil has to serve in the form of a spoon, it gains concavity. This could happen in one of two ways; if the food to be eaten is a warm liquid like soup, the flat utensil could be submerged in the liquid, and the concavity of a spoon would quickly appear. If the food to be eaten isn’t a liquid or is not hot, the user could place the flat form spork in their mouth for short duration, activating the concave geometry.

All that said, creating a sturdy flat-pack 4D printed spork with low activation temperatures and is food safe is way more complex and less defined than a traditional injection molded spork, but I think a morphing spork is way more interesting :)

Second Order Gauss Quadrature

At various points in my life, long division, the unit circle, completing the square, projectile motion, the work-energy balance and most recently, Pulse-Width-Modulation, have all been things that I thought were the coolest thing I’ve ever learned. However, in the details of the least interesting part of a very unassuming idea in numerical methods, I have found something way way more interesting than anything I’ve ever learned ever. This is the closest thing to magic I think I’ve ever seen.

This is the fact that second order Gauss Quadrature is third order accurate. What does that mean? Well consider the equation below

Screen Shot 2018-11-08 at 12.39.35 AM.png

Looks like a pretty rough function to deal with! Integrating it over almost any range would be pretty much impossible, if integrating by hand. But weirdly, the following absurdly cool relationship is true:

Screen Shot 2018-11-08 at 12.36.56 AM.png

All that’s to say that as second order Gauss Quadrature is third order accurate, you can find the value of a third order or lower function integrated from -1 to 1 just by summing the original function’s value at -1/sqrt(3) and 1/sqrt(3). Which is absurd! It’s an incredibly great approximation method using just two points!

Wool Slippers

In Special Topics in Do-It-Yourself Fabrication, the final project is to create literally anything that brings joy to a person and employs interesting fabrication methods. I decided I would:

1] Find a farm that sells wool.
2] Go to the farm, get some wool.
3] Fabricate a mold for a slipper.
4] Use wet felting to make the shoe.

And then I will have a local, low cost, super cool looking ultra comfy pair of shoes I made myself. Potential challenges include the fact that I have literally never done any soft fabrication and don't know anything about shoes.

A university setting encourages building high complexity things by making tools and information more accessible (TAs, Arduino, desktop 3D printing, etc...), but a side effect of this is that we don't often engage with the lower levels of abstraction of a project. When I want to build a part, luckily I don't also have to build a computer, CAD software, and a 3D printer. But what does it feel like to build a low complexity good from scratch? Will it feel like engineering? Or more Design, Art, Science?

Maybe this isn't nearly as lofty an idea as it feels like, but at the very minimum, I'll end up with a pair of slippers.

Tuesday, March 20th 2018

Possible Farms Identified: White Dog Farm or Wild Rose Farms. Both about 30 miles outside of Pittsburgh. Also considering a booth or clog instead or in addition to a slipper.

Wednesday, March 28th 2018

Submitting project proposal! Have watched like 10 hours of youtube videos on various wet felting methods.

Wednesday, April 25th 2018

Called some farms. No calls back.. I have ordered some wool from Amazon. I'm less certain I'll be able to make it to a farm that is nearby with roving for sale during this part of the season.

Friday, May 4th 2018

Final product turned in! Turns out making slippers is not easy. Final product: one single okay looking shoe, but a whole lot more knowledge of wool roving and wet felting. ☺