Finding and Duplicating Awkward Angles

How to find Roof AngleNothing beats having the right tool for the job. If the only tool you have is a hammer, everything starts looking like a nail… and that can be hazardous to your project’s health! The word ‘tool’ doesn’t have to mean things like hammers and screw drivers, it can also include Measuring Tools. Measuring Tools are often overlooked but extremely useful and using the right tool for the job is extremely important. For example, you wouldn’t measure the thickness of a piece of paper with a ruler, or determine the weight of a car using a bathroom scale.

I found myself needing to measure the angle of a roof line then cut a piece of wood to match that angle. How would you do it? Protractors are used for measuring angles but one from your days of elementary school won’t cut the mustard here. Well, I ended up making a tool that will mimic the roof angle and allow me to transfer that angle to my work piece. And the best part may just be that it cost $0 and made completely from some scrap wood and a bit of hardware kicking around the NESIT shop.

Angle Finder PartsThe pieces you see here are made from 3/4 inch plywood. They were already ripped to about 2 inches wide, although the wood width for this angle finder project is not important. Actually, no dimensions are really that important! We are only interested in an roof angle measurement. Notice the two holes, those will be used as a pivot point for this angle measuring tool. The pieces were cut to length on the power miter saw and the one radius was created via the sander.

Angle Finder AssembledThe hardware in the photo consists of a 1/4 inch carriage bolt, washer, lock washer and a wing nut.

Here’s how the parts are assembled. The square portion of the carriage bolt is hammered into the wood to keep the carriage bolt from spinning. The wing nut is used to tighten or loosen the assembly. However, it is best to leave the wing nut tight enough so that the pieces can pivot with a firm force.

You may be wondering what that radius is for. If there was a corner present, it could stick out past the outside edge of one of the legs which would prevent the leg from lining up against a piece of trim on the house. This phenomenon can be seen in the next photo where the corner of the board is poking out below the bottom edge when the angle finder is closed. Luckily though, the tool wouldn’t typically be used in such a closed orientation.

Angle Finder Closed

The below photo shows how the assembly opens, pivoting on the carriage bolt. The angle measuring tool still wouldn’t be used in such a closed orientation. This photo shows the tool open about 45°. The intent is to hold the long leg up to the trim on the the side of the house, then adjust the shorter leg to match the roof angle. The wing nut is then tightened to lock the angle. The tool is then aligned to the piece of wood to be cut, a line traced using a standard pencil, then the board can be cut with a saw… following the line.

 

Angle Finder Open

With this tool, there’s certainly a chance that the angle could change between taking the measurement and tracing it to the work piece. For that reason, I made some protractor reference marks on one of the legs. When the corner of the other piece is lined up with an angle mark, the outside edges of the tool are at the corresponding angle. The intent isn’t for this to be precise, but a general ball park for the user to understand if the angle changed between measuring and marking.

Roof Angle Finder Protractor

So how did I know where to make those angle indication marks? That is a great question and it has a simple answer: I used the trusty rafter square. No doubt you’ve used one to make a 45 or 90° mark on a piece of wood but it is much more useful than that! It can be used to find a bunch of angles. There is a corner of the square marked ‘pivot’. Line this point up with the edge of the wood. Then pivot the square so that the same edge of the wood lines up with a number on the scale. That indicates the square’s edge is at the corresponding angle in relation to the wood’s edge. See below, lining up the pivot point and the ’20 line’ with same edge of the wood creates a 20° angle. I used the rafter square to set the angle of my new tool, then marked the angle with a pencil.

Rafter Square

 

 

Whitehat Wednesday is back – Intro to x86 Assembly

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We are bringing back Whitehat Wednesdays! Our first class/workshop will go over the basics of Assembly language.

When: Wednesday, December 23 – 7:30pm-9:30pm
Class Prerequisites: Must have a basic understanding of the C programming language, as this class will show how C code corresponds to assembly code.
Lab Requirements: Requires a Linux system (recommend Kali) with gcc and gdb

 

This class serves as a foundation x86 assembly language. It teaches the basic concepts and describes the hardware that assembly code deals with. It also goes over many of the most common assembly instructions. Although x86 has hundreds of special purpose instructions, students will be shown it is possible to read most programs by knowing only around 20-30 instructions and their variations.

The instructor-led lab work will include:

* Stepping through a small program and watching the changes to the stack at each instruction (push, pop, call, ret (return), mov)
* Stepping through a slightly more complicated program (adds lea(load effective address), add, sub)
* Understanding the correspondence between C and assembly control transfer mechanisms (e.g. goto in C == jmp in ams)
* Understanding conditional control flow and how loops are translated from C to asm(conditional jumps, jge(jump greater than or equal), jle(jump less than or equal), ja(jump above), cmp (compare), test, etc)
* Boolean logic (and, or, xor, not)
* Logical and Arithmetic bit shift instructions and the cases where each would be used (shl (logical shift left), shr (logical shift right), sal (arithmetic shift left), sar(arithmetic shift right))
* Signed and unsigned multiplication and division
* Special one instruction loops and how C functions like memset or memcpy can be implemented in one instruction plus setup (rep stos (repeat store to string), rep mov (repeat mov)
* Misc instructions like leave and nop (no operation)
* Running examples in the Visual Studio debugger on Windows and the Gnu Debugger (GDB) on Linux
* The famous “binary bomb” lab from the Carnegie Mellon University computer architecture class, which requires the student to do basic reverse engineering to progress through the different phases of the bomb giving the correct input to avoid it “blowing up”. This will be an independent activity.

 

Facebook Signup: https://www.facebook.com/events/943308802415260/

FAA Now Requires Model Aircraft Registration

Tarot FY650 Quad Photo credit woozie2010
Tarot FY650 Quad, Photo credit woozie2010

The FAA has mandated anyone operating model aircraft over 250 grams to register. It’s one registration number that’s used across your vehicles. This does apply to traditional fixed and rotary wing model aircraft. If you don’t want to pay the fee, it’s refundable for a period.

“The normal registration fee is $5, but in an effort to encourage as many people as possible to register quickly, the FAA is waiving this fee for the first 30 days (from Dec. 21, 2015 to Jan 20, 2016).”

It’s not clear if your name and address will be added to a public database similar to FCC amateur licenses and conventional piloted aircraft. The minimum age to register is 13. This is a retroactive policy meaning you’ll need to register and mark existing aircraft prior to flight after Dec 21.

[ FAA Press Release  |  PDF of the Full Rules ]

Pi Zero

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Today we received our first Pi Zero, Priced at just $5, we were lucky to get one the 100 orders available from Adafruit at 2am on Thanksgiving morning. Now just to figure out what project we are going to utilize this in 🙂
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Pi Zero features:

  • A Broadcom BCM2835 application processor
    • 1GHz ARM11 core (40% faster than Raspberry Pi 1)
  • 512MB of LPDDR2 SDRAM
  • A micro-SD card slot
  • A mini-HDMI socket for 1080p60 video output
  • Micro-USB sockets for data and power
  • An unpopulated 40-pin GPIO header
    • Identical pinout to Model A+/B+/2B
  • An unpopulated composite video header
  • Our small form factor, at 65mm x 30mm x 5mm

SawStop – New Tool

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Earlier this year we had a successful fundraiser for a new SawStop. We chose the saw for safety reasons, the saw blade carries a small electrical signal, which the safety system continually monitors. When skin contacts the blade, the signal changes because the human body is conductive, this causes the blade to drop and fall so the user is not harmed. All this happens in less than 5 milliseconds!

We spent the last week putting it together and testing. Last night member Katie taught the first safety and use class to some other members.
katiesawstop katiesawstop2

Casting Aluminum with Mini-Foundry

The goal for our casting experiment is to expand the number of materials our space is capable of working with and creating more durable parts. And at a price of under $20 , this project was perfect. Charcoal foundries can reach temperatures in excess of 1,000ºC which is plenty for us to melt aluminum. It’s melting point is only 660.3°C


Roughly following the instructions from the King of Random, we created a form consisting of two plastic buckets and pouring in conventional quick-drying cement.
casting - Form
After trimming down the excess, we created a steel crucible out of an expired fire extinguisher. Using a hacksaw to cut the top off, it left for a nice smooth steel cup.

 

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The burner is a Reil burner design and propane fed. Our first experiment was melting down a small collection of CPU heatsinks and casting ingots in a steel muffin pan. We were going to use our recycled soda cans but they have thin walls that oxidize quickly and the plastic coatings on the cans add impurities.
Casting - PouringCasting - Ingot

In retrospect, we should have used a cardboard form that would be more easily removed and line the interior of the furnace with replaceable fire bricks. Going forward, we now have conventional casting sand and will be trying to cast 3D printed components.

Greater Hartford Mini Maker Faire

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Join NESIT for the first ever Greater Hartford Mini Maker Faire on October 3, 2015! This family-friendly celebration of invention and creativity is open to people of all ages who are interested in creating, making, building, innovating, tinkering, hacking, engineering, designing or connecting. Maker Faires serve as hands-on events that showcase projects other makers have worked on, while sharing new forms of innovation and experimentation across a range of disciplines.

What types of projects will be showcased?

  • Engineering
  • Robotics
  • 3D printing
  • Arduinos and other microprocessors
  • Student projects
  • Custom tools
  • Science demonstrations
  • Design
  • Food/agriculture
  • Biotechnology
  • Wood, glass, and metal work
  • Many more!

Boscov's Grand Opening – Donate to NESIT

Join Boscov’s in supporting the NESIT. Buy your ticket, $5 each, and your entire purchase helps us! Your ticket gives you: an exclusive first look at Grand Opening Specials, refreshments and entertainment, register to win free prizes, and receive a free gift! Tickets will be mailed from NESIT. Please bring entire ticket & stub to the event!

Boscov’s Gala Preview: October 8, 2015 10AM – 9PM Westfield Meriden Mall

About Boscov’s: Boscov’s has a rich history of serving the needs of our loyal customers by offering a broad assortment of high quality merchandise and setting the gold standard in customer service. Having started more than a century ago with Solomon Boscov’s dream and his pack containing $8 worth of merchandise, Boscov’s now is America’s largest family-owned Department Store, with 43 locations across six states and a growing eCommerce business serving customers across the United States. www.boscovs.com

You can purchase from us when you visit NESIT in person, or you can purchase online from Paypal button below. Make you sure you add your mailing address in the “Add special instructions to the seller:” section.





Temp sensors with Raspberry Pi and PHP

As part of the cheap home automation project I am currently working on, I needed to get some temperature sensor info to my webserver. For the brain of my project I’ll be using a Raspberry Pi.
I had ordered a 5pk of DS18B20 temperature sensors so i can visualize monthly temperatures and eventually control my thermostat. In order to get the sensors working on the Pi, I needed to do a few things:

First I had to setup the pi to add OneWire support. I started by editing the boot config file with nano by running sudo nano /boot/config.txt , I scrolled to the bottom and added the following line:

dtoverlay=w1-gpio

then pressed ctrl+x and y to confirm, then sudo nano /etc/modules add the following 2 lines to the bottom:

w1-gpio
w1-therm

I again press ctrl+x and y to confirm , then shutdown my pi.

I then hooked my sensors up to a 4.7k pullup resistor using the following diagram:

DS18B20
ds18b20-pinout

I booted my Pi back up and tested to see that my sensors were detected by typing the following command into the terminal:

cd /sys/bus/w1/devices
ls
cd 28-xxxx (change this to match what serial number pops up)
cat w1_slave

if all goes well you shouldnt have seen any errors and it should have outputted some gibberish like this:
modprobe
The temperature is shown in the last five digits on the second line. (You need to divide this number by 1000 to get the temperature in degrees Celcius).

You finally need to have Apache2 and PHP5 installed on your Pi.

I had looked online for php code that had outputted the temperature from sensors and found that everyone had hardcoded the sensor ID’s in their code , since I wanted my automation to be as painless as possible, I wrote my own php script to automatically get all the sensor ID’s and then convert the output to Celsius and Fahrenheit. I have this on my Github ::HERE::

Add temp.php to /var/www/ then visit http://127.0.0.1/temp.php

Page output should look similar to this:

Sensor ID#: 28-0214640d18ff = 26 °C / 79 °F
Sensor ID#: 28-02146409b9ff = 25 °C / 77 °F

And that’s it! I will be added more posts as i finish each portion of my home automation project. My goal is trying to get it all done for less than $150.