Welcome to my website! You can explore my entire blog below, all the way back to October 2010, or filter it to see just posts in the Robots or Photography categories.

There are also static accumulation pages that cover stuff from specific categories the blog in one place, which you can access from the header above. If you’re here for math notes, go to leonoverweel.com/mathnotes.

PS: There are Easter eggs hidden on the static pages of this site; see if you can find them! Also, this post is sticky, newer ones are right below.

Dual Axis Motorized RC Camera Rig for Lumia 928

By on July 24, 2013

I got a new phone a couple of weeks ago: the Nokia Lumia 928. It has a great camera, so I decided to build a rig for panning and tilting it.

The robot features two degrees of freedom that can be manipulated independently, is controlled through Bluetooth via an easy to use remote, and rotates the phone exactly around where the lens is located. I’ll get into all those things individually after the video; building instructions are at the bottom of the page.

Lumia Rig demo video


The robot itself has two motors. The first moves a single small gear that spins the turntable and pans the phone. The second is a little more complex; it drives a worm wheel through the center of the turntable, which, through another series of gears, is responsible for tilting.

To get rid of the obnoxiously high amount of vibrations caused by the Mindstorms NXT motors at high speeds, the entire base rests on the rubber shock absorbers that come with the NXT set.

The remote is very minimalistic, featuring a symmetrical design with two motors on the sides that are used to input remote control data into the system, and nothing else. Both follow the red with shades of gray color scheme I’ve been using for most of my robots lately.


The remote and the rig are both programmed in RobotC and connected via Bluetooth; three types of signals (control mode, motor A speed, motor B speed) are encoded and sent between them 33 times a second.

The “control mode” variable tells the rig what mode the remote is in: you can either control the position, where the rig quickly moves the same amount of degrees the remote control wheels are turned, or the speed, where the dials control how fast the motors use. The other two variables then tell the motors how much to move.

Because of the hardware design, if the base were to spin while the tilting motor stands still, the camera would still tilt (the gears would rotate around the worm wheel and spin themselves). To compensate for that, the remote makes sure the worm wheel is always spinning at 1/7th the speed of the panning speed; that speed is then increased or decreased to tilt. This allows for truly individual control over the different functions of the rig.

Build Your Own

If you’ve got a Lumia 928 and would like to build this robot yourself, you can use the resources below.

If you have a different phone: the robot was designed to be adjustable for different sized phones fairly easily.

UPDATE: My friend over at One Mindstorm has created a version of the Lumia Rig optimized for iPhones. You can check it out here for building and programming instructions.

If you have any questions, tweet them to me and I’ll get back to you ASAP.

NYC Chinatown & Little Italy Cinemagraphs

By on July 21, 2013

I went to the city with my parents a couple of days ago. I took lots of regular DSLR pictures, but also tried out taking Cinemagraphs on my phone for the first time:

Lots of people sitting around here, mostly playing board games and cards. Some tables had quite the crowd of spectators around them.

View outside the restaurant where we ate.

Steaming hot pots of food at another restaurant we walked by.

The Little Italy sign changed colors every couple of seconds.

Two cowboys having a drink at a Little Italy bar.

RHS Science Research Symposium Flyer Robot

By on June 25, 2013

The RHS Science Research Symposium Flyer Robot, about to hand out a program.

A couple of weeks ago, we had our annual Science Research symposium, where Rye High School students show visitors the research they’ve done over the year in either a poster or PowerPoint presentation.

A poster I drew for the symposium, featuring illustrations for everyone’s research.

For my research, which I’ll share more about later, I built a demo robot to hand out the flyers/ programs to the people who came by. See the video I made of it below:

Device-wise, the robot consists of the following functional parts:

  • 2 Mindstorms NXT Intelligent Bricks (1.0 & 2.0)
  • 2 100mm Firgelli Linear Actuators ~
  • 2 Mindstorms NXT Motors
  • 1 LEGO Technic Small Motor
  • 4 Mindsensors Flexi-Cables for NXT (1 meter long & 1.5 meters long) ~
  • 1 Custom-made NXT-Technic Motor cable ~
  • 3 Touch Sensors
  • 1 Ultrasonic Sensor

As for how it worked, the process was fairly simple; it’s explained in the gallery below:

After the Ultrasonic Sensor registers a new visitor, the Master NXT (“Jeeves”) sends a Bluetooth signal to the Slave NXT (“Alfred”), which would then turn four wheels that push the bottom program into the arm’s gripper.

Then, Alfred closes the gripper to grab the program once its pushed forward enough to hit a touch sensor (that in-focus gray axle extends into the sensor.)

Once a Bluetooth signal is sent back when Alfred finishes, Jeeves uses the Linear Actuators to move the flyer to the desired position.

A second joint, also controlled by Jeeves, assists in handing out the flyer.

Finally, Jeeves once agains signals Alfred to let go of the program, and the arm returns to its default position, assisted by two more touch sensors used to calibrate different parts of the arm.

Originally, I’d also planned to use an IMU to measure when the visitor grabs a program and only let go of it then; due to time constraints, however, I decided to just use a two second timer. The arm itself, as you can see in the video, is pretty shaky too, so it would have been hard to filter out those vibrations from those caused by a potential visitor grabbing the program.

Overall, though, I’m happy with how the arm turned out, and I’m glad it attracted some people to my poster.

Celebrating 50+ FCCYSF Videos and 50+ Subs

By on June 24, 2013

About a year ago, I started FCCYSF, a YouTube channel to host Creative Commons stock footage available for anyone to use completely for free, with neither upfront nor royalty costs.

Some featured FCCYSF videos

I’m proud to say the channel has recently passed 50 subscribers, and has over 50 videos uploaded. Right now, I’ve started contacting more people possibly interested in contributing. Other than myself, there is one so far.

If you’re interested in becoming a contributor (you’ll get a 70% cut of the advertisement profits made on your footage), or know anyone who might be, drop me an email at fccysf@gmail.com.

The Minerals Page for Just Over Art

By on June 18, 2013

My mom has recently started using epoxy resin to make multi-layered paintings, and they look great. Some of her newest ones are centered around different types of rocks and minerals, which are what the page on her site I made showcases.

Screenshotting it hasn’t given me any good results due to scaling and such, but you can check it out right here. Here’s a picture of one of the paintings instead:
One of Lisette Overweel's Minerals paintingsOne of Lisette Overweel’s Minerals paintings, as seen on her site.

The basic idea behind the page is that there’s a static background that can adapt to anything from a 2560p Cinema Display, to a 16:9 Surface held vertically to a smartphone; the content scrolls in front of it, boxed in by a white background.

The background also adapts to browsers that don’t allow for it to be static, and instead duplicates itself. The way that works without being ugly/ inconsistent is that every other one is vertically flipped, so that there are no harsh breaks between the tops and bottoms of any two occurrences of the image.

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Science Olympiad 2013

By on April 2, 2013

Our local 2013 Science Olympiad was held in late February and my friend Michael Chen and I, among others, represented Rye High School for the Robot Arm challenge. We did fairly well and finished in 7th place.

Our arm features four controllable Degrees of Motion: the base rotates, the arm moves at the shoulder and elbow joints, and the gripper opens and closes. Although it wasn’t driven by any motors, the wrist the gripper was attached to moves too, always keeping itself vertical assisted by gravity.

It was controlled using a Surface Pro running RobotC, connected to the base via USB cable. On the Surface, the interface was fairly simple: the up and down arrow keys on the keyboard or the remote NXT shifted which of the robot’s functions was being controlled, while the left and right arrow keys executed the selected function. The NXT brick connected to the computer relayed its commands to the second NXT brick via Bluetooth.

The code for the master is available here and the code for the slave is available here.

We’re planning to enter again next year, and there are a lot of things we’ve learned that we’ll use to make improvements in both the robot itself and our competition strategy.

This Site

By on March 30, 2013

By now, after a couple of months of on and off work, I’m pretty certain I’m happy with the way this site looks and feels. It’s got a solid grid-based foundation, simple CSS classes to fit content within the frame, all the static pages I can think of, a header and a footer, and now a WordPress-powered blog to push out updates, like this one.


This site, leonoverweel.com, is meant to unify and replace my other sites, World of Mindstorms and NY Snapshot, and to be a portfolio of stuff I’ve done. The static pages, linked above, mostly take care of the latter while the blog this is posted on replaces the two old blogs; it’ll cover topics like these:

  • Robotics
  • Photography
  • Software/ Programming
  • Web

I’ve imported most of the posts from the other two blogs, but they haven’t been optimized for this layout; so, disclaimer: any post older than this one is not guaranteed to look good.


Horizontally, most content on the site fits into a grid consisting of four 200 pixel wide columns with 10 pixels in between each, adding up to 830 pixels of total width. That gives you content that can be 200, 410, 620 or 830 pixels wide, or of course combinations thereof, as illustrated below.


The blog is generally restricted to just the left three quarters, with the fourth quarter left open for the post author, date and title; the picture above is an exception.

At the top and bottom of every page, a header and footer respectively contain quick links. Both following the grid like the rest of the site, the header links to social networks and bigger static portfolio-type pages, while the footer has miscellaneous links.


You may have noticed that my other blogs haven’t seen too many new posts since the school year started, which was mostly, well, because of school. Sophomore year is pretty busy, but now that I’ve started Science Research at least I have a period every day to work on robot-type stuff.

Right now I’m researching HCI, Human Computer Interaction, pointed toward robotics of course, and I’m working on some RobotC-based Mindstorms NXT software for robot arm hardware abstraction.

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