Applied Science

This is a coffee table that I built with a fluid-filled disc on the top. The disc can be rotated freely, and the speed and direction of the rotation will cause the fluid to swirl around in different patterns. The fluid is called rheoscopic fluid -- it is designed to show the intricate patterns in turbulent fluid flow. More here: http://benkrasnow.blogspot.com/2013/01/rheoscopic-coffee-table.html

I am testing an Osram 1000W short arc lamp with a DIY power supply built from an arc welder, auto ignition coil and some other parts. My plan is to build the arc lamp into a searchlight housing.

I mixed: 40g water 25g potassium dichromate 500g concentrated sulfuric acid http://books.google.com/books?id=Fl57Byhp0ecC&lpg=PA114&ots=wYk-A7i9px&dq=delrin%20etch%20chemical&pg=PA114#v=onepage&q=delrin%20etch%20chemical&f=false I guess this mixture is commonly called chromic acid. Things that I should have done: Use a Pyrex beaker Don't use the magnetic stirrer, just use a teflon stir stick Use an ice bath at the beginning of the procedure

In this video, I am repairing a Genesis 12" subwoofer driver. I bought a foam replacement kit from speakerworks.com, and the process of installing it went very smoothly. The song is One Less Worry by Dennis Chambers and Niacin. It's off the Drum Nation Volume Two album.

In this video, I describe how I make fondant cakes. Cake recipe: http://www.recipezaar.com/recipe/Dark-Chocolate-Cake-2496 Buttercream frosting recipe: http://www.recipezaar.com/Vanilla-Buttercream-Frosting-From-Sprinkles-Cupcakes-222188 Part 2 - http://www.youtube.com/watch?v=SaBI6IjIGy0

Cake: http://www.recipezaar.com/recipe/Dark-Chocolate-Cake-2496 Buttercream frosting: http://www.recipezaar.com/Vanilla-Buttercream-Frosting-From-Sprinkles-Cupcakes-222188 Fondant: http://whatscookingamerica.net/PegW/Fondant.htm Part 1 - http://www.youtube.com/watch?v=_IhibizyrtU Part 3 - http://www.youtube.com/watch?v=OkGUzFKQhzY

Part 2 - http://www.youtube.com/watch?v=SaBI6IjIGy0

I am showing a method of using a CdS photoresistor to control a standard triac dimmer circuit that is wired to an electric drill motor (a universal motor). The CdS photoresistor is driven by an LED that is controlled by a PWM pin on an arduino microcontroller. This system provides a very easy way to control 120V AC devices with a single PWM pin, and not use any timing code or method to detect the zero-crossing of the AC power since this is done intrinsically in the circuit. It also offers true electrical isolation between the AC line voltage and microcontroller.

This is an interactive art project that I have been building for an upcoming exhibition. The idea for a web-controlled watering can come from the first "iphone watering can" that I helped build with a friend for Maker Faire a couple years ago. Search the internet/youtube for "iphone watering can" for details. This new version uses a different drive mechanism and a PD control loop to make the watering can track the desired position in realtime. The interface works with any webkit browser. My collaborator and I have discussed using the iphone or android accelerometers to achieve control through phone tilting. I'm not sure if the tilt data is available to the web browser, though, and we are trying to make the interface run on as many platforms as possible. Any ideas? The siteplayer webserver is extremely old technology and has many problems, but does work. I would explore using a hacked WRT router in the future for similar projects. http://benkrasnow.blogspot.com/2010/09/web-controlled-watering-can-and-vortex.html

I built this remote focus control for my telescope, which will eliminate vibrations caused by touching the focus knob with my hand.

I am trying to develop a low-cost DIY thermal imaging device. The commercially available thermal imaging cameras still cost well over $1000 because of high production costs and low demand. Many hobbyists would like to have a cheap thermal imaging camera even if performance is not as good as commercial or military units. My goal is to build such a camera. In this video, I am testing one possible approach: Using a very thin projection screen that is painted with thermochromic liquid crystals. These liquid crystals change color in the temperature range 77*F to 86*F. Ideally, the projection screen housing would be heated (or cooled) to 77*F, so that all incident thermal radiation would raise the screen temperature higher than this, and immediately cause a color change.

I finally finished the 1000W xenon searchlight project that I started earlier this year. The power supply is a slightly modified arc welder coupled with an automotive ignition coil for the starting pulse. http://benkrasnow.blogspot.com/2010/10/diy-searchlight-housing-for-1000w-xenon.html

I need to tap a lot of holes in plastic for my job, so I found a method that is much faster than tapping by hand.

I describe how I built a 10-finger flex sensor system using batting gloves and a National Instruments analog capture device. http://benkrasnow.blogspot.com/2010/12/diy-10-finger-flex-sensor-gloves-for.html

I have designed and built a joystick that contains no electronic parts -- only fiberoptics. The motion is sensed via quadrature encoding, and the signal processing is handled by an arduino microcontroller. How to terminate fiberoptics: http://www.youtube.com/watch?v=OosMQHQlY40 http://benkrasnow.blogspot.com/2010/12/fiberoptic-joystick-with-quadrature.html http://benkrasnow.blogspot.com/2010/02/linear-position-tracking-with.html