At the Range

 This morning, I headed out to Minute Man Sporting Club with some of my friends to practice with the MIT Sporting Clay's club. We played two rounds of Trap. Trap is a game where small clay targets (4" diameter) are lobbed into the air, players attempt to pull up onto the targets with a shotgun loaded with what is effectively bird-shot and 'break' the targets.

My best round was 20/25 targets which I thought was pretty good for being out of practice. Of course, we were also playing at the shortest distance and hitting targets was therefore easier than normal competition.



A Small Endmill (1/16")

 Last evening, I tried out the old way of making an inlet inscription on a small aluminum ring I quickly fashioned on the mill. Basically, when nice tapered, carbide end mills were hard to find and make, small end mills were used to cut the entire profile of an inscription.

I found keeping track of my location in thousandths of an inch hard to remember and messed up on the last letter. I learned a bit about small size tooling and some of the CNC "do one" functions on the Proto-Trak systems mill.

22.033 Check Source Boxes and Trefoil Design

I am taking 22.033 this semester. The class has a focus on hands-on learning surrounding the concepts involved with nuclear science and engineering (NSE). The above radioactive symbol is the trefoil. The relative dimensions of this shape are denoted in the Code for Federal Regulations. Traditionally, purple and yellow are used for long term, high visibility as the involved dangers can last for millions of years.

At the left is a bracket for my friend Joseph's new electric long board project.

Below is a picture of my most recent practice on the lathe making a 'door handle' for my friend Jane.

 I recently picked up a super cheap electric scooter. As I sometimes don't want to get my bike out for shorter trips. This transportation solution is my new quest.
This is what a check source looks like. My group in 22.033 has a mission to redesign the boxes used to hold these. Stay tuned for the finished project.

IoTaser // HackMIT 2018

 This week has led up to an event called HackMIT. The event is a hackathon. Where students gather together to tool away at a variety of projects using different software tools and hardware options. One of the main goals for "hackers" at the event is to successfully win a prize offer by a company at the event.

This year, I built IoTaser. It's basically operating a potted, high voltage inverter using a Particle Photon board. The phone app native to the Photon allows me to send pins high/low on the controller which operates a series of MOSFETS in the device to charge a boost converter.


3D printed Hall Effect Holder

 A lot of brush-less, in-runner motors I have run into happen to operate without any sensing capacity. This means the motor doesn't know where it is in a cycle. My friend Greg asked me to print these designs on a Stratasys for this exact purpose. The three hall effect sensors sit in the outer ring which is connected to the frame of the motor itself. As the rotor moves, the hall effect sensors pick up the magnetic field sequentially and notify the motor controller where the shaft sits.

Button Fixes

 There is a small novelty button on the floor below mine. This button is cause for lots of celebration as it makes an interesting noise when pressed. I have found it twice now in an inoperable condition due to people pressing it too hard. I have replacement buttons however, and a short while with a soldering iron gets it back in working order. It's only a matter of time however, until somewhere hits it too hard again. :/

Waterjet ACTION

 Last night, I was working on some constraint strips for my robotics research project. The waterjet is a great tool for accurately cutting interesting profiles in stock as hard as granite. I cut some spring steel strips (~1/8" thick) with this tool and appreciate the user friendly software.

Splicing Wires on EBike and new clamps

 Basically these new clamps keep my lid on properly. Previously, I depended on two whole screws to "seal" my lid from the exterior world. Now, four [read: three] nice folding C-clamps hold it firmly in place.

Unfortunately, the new charging wires I put into parallel with the battery output slightly bulge the enclosure outwards. This is something I can understand though and fix later.





Also, terminal strip connectors exposed to high current jumps (think water hammer) can only go through ~20 or so cycles (during recharging) before they lose serious efficiency and start heating up locally.





Blowing a Battery

 Unfortunately, I ruined a perfectly good Li-Fe-PO4 cell last night. This was a product of possible bad treatment to the 4S2P battery produced by A123 Batteries you see in the picture. I drained the cells completely with my bike and wanted to charge them back quickly by bypassing the in-series fuse to the discharge rail. This definitely charged the pack quickly but it heated up fast and a small quiff of blueberry scented smoke flew out of the battery pack. Breaking LiFe's is much less scary than LiPo but it still smells as bad.
A friend of mine is interested in adding hall effect sensors to a motor, something like this I think. 

Jesus the Ride


A video can be found at https://youtu.be/bcsXWedv_uA

Basically a trebuchet for people. . . There was a large safety factor. . .

Pedalling About



Contrary to what seems like the higher truth (fuzzy logic reference). This post is not about bikes. I like bikes but I also like another kind of pedal. The effect pedal. An effect pedal has two inputs, power and audio-in. The output is audio-out.

This is the schematic I based my design off. I used large voltage biased capacitors and larger pots (greater range).

 The "Fuzz" pedal is a simple circuit for beginners. The schematic basically depicts a dual stage amplifier with capacitor in series to the input. The sound that goes through sounds as if it has been cut many times a second briefly and amplifies to saturate the capacitor. This happens many times a second when the guitar audio is a strong waveform. 
Simple Art for a simple pedal.

Out in the Fells this Weekend

  Instead of driving out to New Hampshire, the Cedar St friends decided to hike closer to home and visited the Middlesex Fells reservation. ...