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 would ever learned.

However, in the details of a very unassuming idea in numerical methods, I have learned something way more interesting than anything I’ve ever learned heretofore: second order Gauss Quadrature is third order accurate. What is meant by this? 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 such a mess, if integrating by hand. But weirdly, the following relationship is true:

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

All that’s to say that 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). It’s a great approximation method using just two points!

4D Spork

A fork has two states. So too does a spoon. but a spork? a spork has three. This feature is noteworthy.

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.

A spoon and fork each have 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 :)

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 permission, 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

How to Set Up a Raspberry Pi on CMU WiFi

Last Tested in April 2019

Connecting a Raspberry Pi to Carnegie Mellon’s wireless or wired network is a total nightmare. Since I was a student in 2017, this page contains up-to-date instructions for connecting a device in the least convoluted way.

Based on what you have access to, follow one of the three instructions below.

1) A Raspberry Pi, a mouse, keyboard, and monitor, and SD card → Preferred Desktop Set Up Instructions

2) A Raspberry Pi whose MAC address is known or can be known from previous projects or set-ups, a device with network access and an SD card slot (like a laptop), and SD card → Preferred Headless Set Up Instructions

3) A Raspberry Pi whose MAC address is unknown, and SD card → Alternative Headless Set Up Instructions

Option 1: Preferred Desktop Set Up Instructions (easiest)

If you have a mouse, keyboard, and monitor, and SD card, you can boot your device and connect to the network with the GUI.

  1. Ensure your device has an OS on in, or start by flashing Raspbian Desktop to your SD card.

  2. Insert SD card. Connect mouse, keyboard, and monitor.

  3. Boot up, and connect to CMU-Secure using the GUI (select the stadium seating Wi-Fi icon and use your CMU-Secure log-in credentials

  4. If you need to enable SSH (remote shell access), open Preferences> Raspberry Pi Configuration > Interfaces tab > Select Enabled next to SSH > Click OK and close the window.

  • You’re done! Enjoy your RPi.

Option 2: Preferred Headless Set Up Instructions

If you don’t have a mouse, keyboard, and monitor, you can boot your device and connect to the network “headless” with this method long as you already have your devices’s MAC address.

  1. Ensure your device has an OS on in, or start by flashing Raspbian to your SD card

  2. Place your SD card in your computer, and enable SSH on the Pi by placing a file named ssh, without any extension, onto the boot partition of the SD card. You can do this by navigating to the Boot partition in Terminal and entering touch ssh

  3. Insert SD card and boot up your Pi.

  4. Visit getonline.cmu.edu on another device already with network access to register your Raspberry Pi on CMU-DEVICE. Make sure to pick a hostname you’ll remember.

  5. SSH into your device from your primary computer using ssh pi@YOUR-HOSTNAME@wifi.local.cmu.edu with the password raspberry

  6. Immediately change the default password by entering the passwd command, otherwise your device is essentially accessible to anyone on the internet.

  • You’re done! Enjoy your RPi! Connect to it from SSH using your new password with pi@YOUR-HOSTNAME@wifi.local.cmu.edu

Option 3: Alternative Headless Set Up Instructions

If you don’t have a mouse, keyboard, and monitor and don’t already have your device’s MAC address, you’re in for quite a process! Firstly you need your devices MAC address— there’s a few ways you can do this, but we’ll highlight just one, though it requires you to have access to a home (non-cmu and not starbucks/library/etc) wi-fi network.

  1. Ensure your device has an OS on in, or start by flashing Raspbian to your SD card

  2. Place your SD card in your computer, and enable SSH on the Pi by placing a file named ssh, without any extension, onto the boot partition of the SD card. You can do this by navigating to the Boot partition in Terminal and entering touch ssh

  3. In Terminal, navigate to the SD card’s directory, most likely name Boot

    cd /Volumes/boot

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

    sudo nano wpa_supplicant.conf

  5. On your laptop or desktop, go to steveedson.co.uk/tools/wpa and copy the wpa_supplicant text needed for your home wifi network.

  6. Paste (ctrl+v) the text from the previous step into the file, it should look something similar to this

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

network={
       ssid="SOMETHING"
       key_mgmt=NONE
    }

  7. Save the file (ctrl+o) close it (ctrl+x)

  8. Insert SD card and boot up your Pi.

  9. Connect to the same home network as the Pi from a laptop or desktop, and scan the network for your Pi by using a command like arp -a in Terminal. When you spot your Pi copy down its MAC address (no need to note its IP though)

  10. Visit getonline.cmu.edu on your laptop/desktop and register your Raspberry Pi on CMU-DEVICE with its MAC address. Make sure to pick a hostname you’ll remember.

  11. Power down, and place your SD card back in your computer— now we have to tell it to auto-connect to CMU-DEVICE when you’re on campus again.

  12. In Terminal, navigate to the SD card’s directory, most likely name Boot

    cd /Volumes/boot

  13. Edit the wpa_supplicant.conf (this will replace the current RPi wifi config on next boot)

    sudo nano wpa_supplicant.conf

  14. Delete its entire contents, and replace it with this

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

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

  15. Save the file (ctrl+o) close it (ctrl+x)

  16. Move your device to campus, Insert SD card and boot up your Pi.

  17. Wait a few minutes, then SSH into your device from your primary computer using ssh pi@YOUR-HOSTNAME@wifi.local.cmu.edu with the password raspberry

  18. Immediately change the default password by entering the passwd command, otherwise your device is essentially accessible to anyone on the internet.

  • You’re done! Enjoy your RPi! Connect to it from SSH using your new password with pi@YOUR-HOSTNAME@wifi.local.cmu.edu

Getting a raspberry Pi registered on CMU’s wifi is weirdly one of the most challenging parts of cmu— If you have questions about these instructions, or they are not working, feel free to comment below.

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. ☺

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” (Or something else, if you’d prefer).

  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 gmail.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%40gmail.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 🎉

last updated: june 2020.