Sunday, January 26, 2014

PID Controllers

I have a few ongoing projects where a feedback loop that considers a moving goal and adjusts to achieve that goal is essential. One of these projects is a two wheeled self balancing robot. This type of problem is perfect for a PID control loop. I have been procrastinating biting the PID bullet because I was under the impression that PID was not easy to learn or implement. Thankfully, after much searching, I have found a very straightforward and intuitive overview of PID.

After the above overviews I dug around to find some PID Controller pseudocode.
previous_error = 0
integral = 0 
  error = setpoint - measured_value
  integral = integral + error*dt
  derivative = (error - previous_error)/dt
  output = Kp*error + Ki*integral + Kd*derivative
  previous_error = error
  goto start

I am no longer intimidated by PID. Should be fun.

Thursday, January 2, 2014

Photomosaics: framed

In college in 2008 I did a research project on photomosaics. More info can be found in another blog post. One of the mosaics I created was of Albert Einstein's eyes. It even captured the twinkle. Ever since then it has been a source of inspiration for me. This xmas I asked for it to be framed so that I could hang it in my workshop. Here it is behind my desk.

So happy right now...

Tuesday, December 31, 2013

tv: 3d Printable Rubber Band Gun

Designing a printable rubber band gun has always been on my bucket list. I used the holiday season as an excuse to finally do it. You have to fight consumerism somehow, right? And what better way to fight it than to print rubber band guns for your relatives.

Of course I'm releasing this to the community. Here are the files you will need to print one for yourself:

Saturday, August 10, 2013

tv: The Scratch Flight

Building a remote controlled plane from scratch has always been at the top of my bucket list. This week I popped it off the stack, built, and flew! You could argue what I did isn't really flying. I might agree with you. Ha. But it's a start. I just need LOTS of practice!

I built this plane out of dollar tree foam and packing tape by following the masterful tutorials of Experimental Airlines.

Thursday, June 6, 2013

How to Organizing your Tools with DIY Modular Magnetic Strips

I'm not the most organized person by nature. But the more organized I get, the more I realize how important it is for productivity. The more organized I am, the more productive I am, plain and simple. I've been looking for a way to be more organized with my tools. Before today I kept them in some random bins if they were for a specific project, or in my toolbox if they were for a general purpose. But I still had difficulty finding what I needed when I needed it. I couldn't see them!

A few days ago a friend shared a link to an article on Cliff Stoll, a real life mad scientist. He's even got the hair to prove it. Here's the article. In the article there's a picture of how Cliff organizes his tools using magnetic strips. How simple!

I looked around amazon for some magStrips, but I didn't like what I found. They were expensive, and none of them were modular. I like modular. So I looked around craft stores and home improvement stores and came up with a jaw dropping DIY modular solution!

First, I needed a surface to mount the magnetic strips. I created a frame from pine 1X2s to support a panel of Tempered Service Perf.

I then bought 100 0.5in diameter 1/16in thick Neodymium magnates.

I made a 5 layer sandwich of:
  • 0.5in X 1/8in steel flat
  • magnets spaced 1in apart
  • 0.5in steel tube
  • magnets
  • steel flat

I then printed ends that snapped into the center of the steel tube and hooked into the perf board. Here's the part, if you wanted to print it:

Since the magnetic strips are perf board compatible, and since I have a wall of perf board now, I can arrange them in any way I need. I can also use any of the existing perf board hardware, like hooks and baskets. Here's the finished product:

If you found this info helpful, let me know! If you have tricks you use to organize your tools and your workspace, I'd love to hear them!

Thursday, April 4, 2013

RepRap - The Viral 3d Printer

Midwest RepRap Festival: Video 4 of 6 | 14:34

This is the 14 minute RepRap documentary from my trip to MRRF. You (my subscribers) and the RepRap community have given me so much! This video is my attempt at giving back. It took a lot of late nights in the editing room, but I'm finally done! Please help The Viral 3d Printer go even more viral!

I traveled to Elkhart Indiana to get more information on the opensource 3d printing movement called RepRap. I interviewed core developers and users of the technology, as well as kids who are growing up with the technology.

On top of the people who allowed me to film and interview them I would like to thank:

Jeff McAlvay works on Board Forge with folks from around the country.
Visit for more info.

RepRap IRC:

Thursday, March 28, 2013

3D printed Quadcopter at MRRF

Midwest RepRap Festival: Video 3 of 6 | 6:02

While at the Midwest RepRap Festival I was able to sit down (while standing) with Russ Reese and get some information on his quadcopter. I don't know what it is about quadcopters, but it's a must have for every robotics loving maker! Russ did a beautiful job on the quadcopter he demos for us!

We would like to thank the following people for making the Midwest RepRap Festival possible:
All the volunteers!