Author Archives: Jeremy Cook

Simple ATtiny Servo Control

ATtiny-arduino-servo

ATtiny, arduino, and a micro servo

This method may not be pretty, but for crude servo control with the ATtiny chip, this method should work.  I programmed it using an Arduino Uno as shown here.

Hobby servos work by taking the length of time a pulse of electricity is sent to the “signal” input.  If it is 1.5 milliseconds (ms), it moves to the middle of it’s travel, 2 ms to the right, and 1 ms to the left.  This excellent paper illustrates this, as well as some standard connector colors, which have helped me with some of my projects.

For my “tiny useless machine,” I needed a way to control a servo using the ATtiny chip.  Accuracy didn’t have to be great, so what I did was used the delay command to make the pulse either 1 millisecond (delay 1) or 2 milliseconds (delay 2).  The code below will show what I mean, Read more »

Lathe Laser Light and Table Tennis Graffiti

lathe-laser-light-graffiti

Laser, Lathe, and Long Exposure

I’ve done a lot of experiments with light graffiti on JCoPro, but some things don’t really go anywhere.  This post is about a few shots that don’t necessarily fit into another large post, but I thought were interesting anyway.

The first few pictures in the gallery after the “more” are of me tracing the supposed trajectory of a Ping-Pong ball with a green laser (under $5 on Amazon as of this writing).  Shining it on the ball itself made for a cool effect.  Yay.

The second set of pictures, made with a lathe, Read more »

Free pyMCU Contest Winner!

pymcu-led-pov-writing

Hello pyMCU - How I did this.

Congratulations to Patrick Gibson on winning the “free pyMCU” contest!*

Richard will be sending the winner one shortly, and if you come up with any cool projects with it, I would love to see it!

In case you’re wondering how I selected the winners, I used a simple Python script (naturally) putting everyone in a list then randomizing it.  Sure, it’s only pseudo-random, but hopefully it’s good enough for readers of this blog.  If I was really good, I’d figure out a way to scrape the comments, but handling the “subscription bonus” would have made it even tougher.

Contest Python Script: Read more »

First Look at OpenSCAD

openscad-sphere

“Disco sphere” made with 1 line of OpenSCAD code

After my review of Meshcam, it was suggested that OpenSCAD (available on various OS versions, or here’s the Ubuntu install instructions) could be used to turn 2D DXF files into solid parts for cutting on my CNC router.  After trying it out, this solid modelling package is really like nothing I’ve ever seen.  Instead of the mouse-driven interface that you see on ProE or Solidworks, you instead have a text editor where you can enter commands that are used to form a solid part.

Oddly, it felt very intuitive to me to use it, and the fact that you can copy-and-paste text into a drawing makes an example extremely easy to follow along with. With professional 3D CAD packages, you may have to poke through 5 menus to get what you need, in OpenSCAD you just type the needed command in.

AutoCAD (or Draftsight – my review) has a text interface that can optionally be used, but it’s interesting to think about what would have happened if other professional CAD packages evolved this way.  My feeling is that it might have made things harder to use initially, but once the interface is learned it would have been incredibly fast.  Fixing a poorly-programmed design or initially visualizing what you wanted might be harder, however.

Hypothetical thoughts aside, OpenSCAD is really a lot of fun to play with.  To draw a sphere, for example, all you have to do is type in “sphere(30);” and press F5.  A 3D sphere pops up on your screen.  As shown in the video after the “read more” thing, Read more »

Shop Vac Noise Reduction Panneling (From Scraps)

shop-vac-noise-enclosure-openEven with a foam muffler on my Shop Vac, (‘Vac available from Amazon) it was still louder than I wanted without hearing protection.  I tried putting a piece of acrylic over the front of it, but when I had a few pieces of scrap wood available I decided to box in two of the sides as shown in the photos below.  I attached scrap packaging material to the inside of them to act as noise-insulation.

I could probably box it in even more, Read more »