Author Archives: Admin

Geeky Stained Glass

It’s nearly Christmas again! I’ve started to learn a new craft, an ancient one, and started to mix it up with modern technology.

Behold, stained glass suncatcher with embedded LEDs

This is essentially black magic to most glass artists and a huge “duh” moment to all the makers and engineers. I’ve been asked to teach how this is done…

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Raspberry Pi Handheld 3D Scanner

I’ve had some fun with photogrammetry recently and wanted to try out other techniques for 3D scanning. I’ve actually sort of accomplished S.L.A.M. during a hackathon using the PlayStation 4 camera and the Xbox One Kinect already, but I wanted something portable! With the new Raspberry Pi 4 debuting this year, I can finally accomplish this… sort of…

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Outdoor Photogrammetry Adventures

I’ve been experimenting with 3D scanning objects outdoors with just a camera! Using Meshroom, an open source photogrammetry tool, I can process a bunch of photographs into a textured 3D model. I could use these models for 3D printing or as objects in a game engine. Anybody with a camera can do this! The caveat is that Meshroom only runs on computers with CUDA.

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Aquarium Computer

This is a mineral oil submerged computer. Mineral oil is a liquid that looks and behaves like water but does not conduct electricity, hence why it is safe to run electronics inside it. The mineral oil also aids to control the temperature of the entire system, by soaking up and removing heat away from hot components like the CPU.

You might have already seen my first computer, which was also an aquarium computer. Something mighty unfortunate happened to it… This new aquarium computer is built with all the lessons learned from the first. Please continue reading to find out the details

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Hephaestus, my own 3D printer

I finally did it, I designed and built my own 3D printer. This is in no way “the best 3D printer”. Instead, this was an epic and nightmare project that exercised my ability to engineer and build my own CNC machine. Along the way, I figured out what I did well and what I did badly, mistakes were made and sometimes fixed, even ignored.

This 3D printer is named Haphaestus. This wasn’t some kit that I purchased and put together, this wasn’t some tutorial I downloaded and followed. I designed almost everything about this printer and built it with tools I own and a waterjet cutting service. The only application specific parts I didn’t design are the Duet controller circuit and the E3D Titan parts.

NOTE: This is not an open source project where I will let you download a few files so you can build one yourself, trust me… you don’t want to. It’ll be a logistical nightmare to just organize the files and BOM to the point where it is useful to anybody else.

This page will be dedicated to recording my experiences and analysis of the first 3D printer I have ever designed and built all by myself.

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Promoting STEM Education at the Library

A few weeks ago, the library consulted me about teaching programming to kids. The Grand Avenue library is already using the CS First With Google and the West Orange library wants to start something similar and asked because of the previous robotics classes I’ve taught for them. While they could also try Google’s CS First, why not experiment with something else? Something a bit more hands on!

The library have always said they wanted to loan out Arduinos but it just can’t happen because of how much other stuff you must include with it before it becomes useful. It is impractical to expect the librarians to count wires and LEDs when an Arduino is loaned out.

So my targets were: low part count, easy to loan and return, full curriculum written.

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Teaching a Robotics Class

I spend my Saturdays volunteering at a public library makerspace, the South San Francisco Public Library. I help people operate a few 3D printers, a CNC mill, vinyl cutter, etc. While preparing for my annual RoboGames entry, I thought it’d be cool to teach the library’s patrons about robotics.

I designed a robot kit, partly 3D printed, with electronics that has to be soldered, and running with an Arduino Nano. The three classes are for 3D CAD modelling, soldering, and programming.

The robots are designed to be cheap enough for the library to actually give away. All of my courseware is open source, hosted on GitHub. A lot of the tools and parts were donated by people I know in my professional circles.

Here’s a link to the class content: click here

This blog post is about what I observed, what I did right, what I did wrong.

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Switching the Public Library 3D Printers to Use Cartridges

Ha, that title makes me sound so evil.

See… this library actually leaves their 3D printers unsupervised, and the patrons use them how they please. I love it, getting people exposed to the latest tech is our goal. But this means that people do not realize how to properly remove filament from the printers, leading to tangles and knots in the filament spools. A single mistake could essentially render a $20 spool useless, it becomes a time bomb for printer jams, making people unhappy.

No amount of posters or instructions booklets could embed the same kind of discipline that a 3D printer owner has regarding filament treatment. Just a simple mistake of letting the filament go could cause a knot in the spool.

My solution… make them use cartridges that make it hard to make mistakes. These cartridges must be cheap, fast to make, easy to understand, reusable, and do not require modifying the printer to use. Don’t worry, there’s no DRM bull**** and they are adjustable to fit any standard spools. If my idea causes more problems than it solves, simply clip all the zip ties and go back to status-quo.

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3D Printed Molds for Small Robot Wheels

For my antweight combat robot DetCord, I wanted a wheel that could improve upon the Banebots wheels that I used before. I wanted something shock absorbing, which would extend the life of my gearboxes. The tires need to be soft and have high traction. The wheel does not have to be very strong because the robot has thick armour to protect the wheels.

I ended up with a cool way to make a wheel that’s cleaner than the more popular methods I see on the internet! Continue reading

Review: Cubiio Laser Engraver

I backed a Kickstarter called Cubiio. It’s a palm sized cube shaped 800mW laser engraver. It is a rather controversial Kickstarter project. I have received and used mine for a bit and I have some personal opinions about it. This is going to be a real review, but from the perspective of an engineer and maker who is already deep into 3D printing and CNC milling. Unfortunately I am unwilling to fully tear it down for analysis as I actually do enjoy using Cubiio, so I can only speculate as to what is inside.

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3D Printed Mechanical Iris Dome All-One-Piece

It’s that time of year when we think about gift giving. I decided to design a dome shaped box that opened with moving curved doors.



(dear iPhone users, sorry if the videos don’t work for you, please consider upgrading)

Keep reading for more pictures and a full tutorial teaching you how to create this in CAD.

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Car Heads Up Display Using LED Strip

This is the next step in my mission to make my car function 7 years newer and feel like a jet cockpit.

(click here if the above video isn’t loading)

I wanted a HUD, Heads Up Display to my car. The main purpose is to let me keep my eyes on the road and still be aware of my speed without looking down, hence “heads up”. This idea has been used in fighter jets for decades now.

I do not like any of the other ones on the market today, they all try to do “too much”. I wanted something more simple and elegant.

My design is a simple RGB capable individually controllable LED strip that reflect off my windshield.

I used the “DotStar” from Adafruit Industries, which uses APA102 LEDs. The brain is a Teensy 3.2, which is connected to my car’s CAN bus via a OBD-II connector (the diagnostic port that you can read the engine computer from).

It is programmed to have three different modes: voltmeter, tachometer, and speedometer. The mode switching is “context aware”: When the car is moving, the mode changes to speedometer. If I rev the engine Continue reading

DetCord – 1 lb Antweight Combat Robot


My 2018 competitor, with a titanium horizontal blade from FingerTech Robotics. I felt like rebuilding a drum spinner twice is too boring so gotta change up the weapon choice every year.

I was the winner of that fight because of the driving I did after my blade broke off. My radio is a FrSky Taranis Q X7 and it has adjustable curves for everything, so I actually had better driving control, better than most other competitors.

The steel shaft of the motor is the problem, apparently a hollow steel shaft isn’t hard enough to handle the impacts. The next video shows the second time the motor shaft broke. I did actually stick a #4-40 steel bolt into the hollow part, it may have made the problem worse, this time instead of just the shaft snapping, the entire plate holding the bearing shattered.


RoboGames 2018

Just dumping media here



Major Components:

  • Banebots T40 wheels and hubs (possibly replaced by custom molded wheels soon)
  • Pololu micro metal gearbox motors (Sanyo style), 6V HPCB, 75:1 gear ratio
  • Fingertech tinyESCs for drive
  • EMAX 30A brushless BLheli_S Bullet ESC
  • EMAX RS2205-S brushless motor with steel shaft
  • Fingertech titanium weapon blade, 6 inch long, 3/16 inch thick
  • FrSky XMR receiver
  • Delrin/Acetal top and bottom plates, laser cut
  • 3D printed body using NylonX (chopped carbon fiber infused nylon)
  • Battery is 2S1P LiPo 20C about 800mAH (advertised as 1000mAH but I don’t trust them)

rLoop Victory

We did it, we said we were going to win and we did. We built something so technologically beautiful that Elon Musk himself crowned it the most innovative of them all.

I am proud to have served on a team where the exact combination of passionate people was key to achieving our success. Every ounce of effort mattered, every single nut tightened, every single wire connected, every word spoken. Thank you all for standing beside me through it all. You are all amazing, and no matter how little you came in with, I hope working together helped you learn, and set yourselves up for a better future.

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Shrapnelly – 1 lb Antweight Combat Robot

This is my first ever combat robot! 454 grams (1 lb American Antweight class). It has a spinning drum weapon.Body is made of Garolite, with titanium skirts mounted on hinges (parts are cut on my Nomad 883 Pro, and some 3D printing). The drum weapon is CNC lathed aluminum with a brushless motor inside. The electronics is all custom built, utilizing the 802.15.4 radio integrated in the ATmega256RFR2.

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Voltage Divider Resistor Chooser

This is a special resistor voltage divider calculator. You tell it what is the maximum expected input voltage and the maximum desired output voltage, and a list of all the resistors you already own, and it automatically picks the two resistors you should use. This is useful because it means you don't have to buy a specific resistor for a project, and you don't have to calculate for every single resistor you own. Continue below to use Continue reading

CES 2016

I went to CES 2016 in Las Vegas. This is my second time visiting CES, last year I made this post (CES 2015) about it too.

This year is a little underwhelming than last year, perhaps its because last year was my first time, and this year is my second time. There are many things that simply remained unchanged, or just slightly improved. Here’s a list of what I found interesting: (continue reading)

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3D Printed Cord Wrap Tool for Microsoft Surface Pro 4

If you owned any good laptops, you might have a charger that had a curved shape, and/or a strap to help you wrap the cord. Well… The Microsoft Surface Pro 4 is an amazing computer but it’s charger doesn’t even have a strap. So I’ve decided to solve this problem with 3D printing.

3dmodelchargetinbutnotwrapped (Large)printed (Large)wrapped (Large)

The filament I used is actually black 3mm polyurethane filament, which is both strong and flexible. Printed using my Ultimaker2, upgraded with a Flex3Drive, at 250 degrees C, layer height of 0.2mm, and 200% extrusion.

Funny that the strap would’ve been too long to be printed straight, that’s why I made it squiggly.

The model file is shared as a public model on Onshape here. Go ahead and download it, or even copy it to your own account to make modifications.

3D Printed Dust Skirt for Nomad 883 Pro

I got a new Nomad 883 Pro and it generates a lot of dust. This is going to be a big problem as I need to cut material that have hazardous fibers. I decided to make a dust skirt (aka vacuum skirt or vacuum shoe or vacuum head) so that a vacuum can suck up dust as the machine cuts. I 3D printed this thing, which is partly PLA plastic, and the skirt is 3D printed TPU (polyurethane) filament. The skirt is two layered and the cuts are made in a interleaved pattern so there’s a better seal. 3D printing makes this project really easy, just clean up the print, superglue, and tap the hole for the screw. The vacuum hose is 1.25 inch diameter and it just shoves right in with a perfect fit.

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The CAD files can be downloaded here