Gain Wizardly Knowledge About Crystals

August 9, 2011 by 19 Comments

Make sure your test equipment is handy, then give this video series about crystal oscillators a spin. [Shahriar] of the Signal Path Blog put together a four-part video blog post totaling about an hour. In the discussion he covers the ins and outs of crystal oscillators and ring oscillators. His focus is on how these parts are used as timekeeping devices for microcontrollers. This isn’t a lecture that skims the surface of the topic, it takes you down the rabbit hole, discussing theory, how the devices are built, how to use them, and the pitfalls of doing so.

Our favorite part is in the fourth segment when [Shahriar] measures the effect that temperature has on crystals by spraying them with an inverted compressed air canister. We always thought we were just screwing around when freezing stuff like that. It didn’t occur to us that we were conducting serious experiments.

We’ve embedded the first segment of the video after the break. Continue reading “Gain Wizardly Knowledge About Crystals” →

Ever Wonder Where Cool Interactive Museum Exhibits Come From?

August 9, 2011 by 13 Comments

[Victor’s] girlfriend works at a museum and enlisted his expertise in designing an interactive detective game for kids visiting the museum. The vision was for the kids to discover phone numbers that they could call for clues. Originally he planned to display the clues on a character LCD, but obviously it’s much neater to hear the clues in the handset of the phone.

Quickly switching gears, [Victor] dropped the ATtiny2313 and started over with an Xmega chip — in fact, it was our recent Xmega post that inspired him to document his project. The microcontroller is responsible for a lot of goings-on. It scans the key matrix for inputs, simulates the DTMF touch tones, reads audio files from a FAT file system on an SD card, and plays them back over the hand set’s speaker. Since most of the hardware is already built into the phones, it was not hard to fit his add-ons inside the case. A simple audio amplifier circuit joins the microcontroller, which is patched into the rows and columns of the keyboard. Take a gander at the video after the break to see the device in action.

Continue reading “Ever Wonder Where Cool Interactive Museum Exhibits Come From?” →

Sous Vide Crock Pot Controller

August 9, 2011 by 12 Comments

Tempted by what sous vide cooking has to offer, but balking at the price for a unitasker, [Lee’s] father in law set out to see if he could rig up his own precision temperature controlled cooking system on the cheap. He immediately hit eBay and shelled out about around $75 to get his hands on a solid state relay, PID controller, and temperature probe.

As you can see above, a crock pot serves as the cooking vessel. We’ve seen this method before, either splicing into the power cord, or providing a single outlet on the controller. This version provides a PID controlled outlet to which the appliance can be plugged in. The other outlet in the socket is always on and powers an aquarium pump that circulates the heated water during the cooking process.

The result works quite well, even though it wasn’t a huge cost savings. There are a few issues with positioning of the temperature probe, but that may be where experience comes into play.

A Robotic Turtle Platform To Buy Or Build

August 9, 2011 by 5 Comments

This electric turtle bot instructable describes a fairly simple turtle-style robot meant to be laser cut out of acrylic (although other materials such as aluminum, MDF, or polycarbonate should work just as well). This frame is also optionally for sale, which should appeal to those that would like a mechanical robotics platform to play with, but don’t have access to machine tools. The build instructions include a detailed bill of materials which should come in handy.

As displayed in the video after the break, the robot uses a sonar sensor to navigate. This sensor is set up on a servo in order to scan the terrain, and, depending on how it’s programmed, hopefully avoid obstacles. As of when the video was taken, the little robot appears to sense an obstacle then scan with the servo left and right to see what the best way to turn is.

[youtube http://www.youtube.com/watch?v=vA_kIY3MvTE&w=470&h=349%5D

If this little turtle robot doesn’t have enough power for your taste, check out this autonomous ATV sentry.

DIY Orb Display Puts The Earth In Your Hands

August 8, 2011 by 24 Comments

diy_spherical_projection_globe

[Nirav] liked the idea of having his own personal Earth at the tip of his fingers, and since that’s not happening any time soon, he decided to build the next best thing. Sure, he could have simply gone out and purchased a globe, but there is no fun in that. Instead, he shows us how he put together an interactive spherical display that won’t break the bank.

The sphere uses a Microvision SHOWWX to drive its display, which projects an image inside of a frosted glass light fixture. The pico projector gets some help from a 180° fisheye lens along the way, enabling the picture to be stretched across the entire inner surface of the globe.

[Nirav] used his 3D extruder to build a base for the globe, which attaches to the projector via a printed mounting plate. A GorillaPod was used to keep things upright while he dusted off his trigonometry skills in order to figure out how to get the image just right.

We think that he did a great job – it definitely looks to be on par (albeit a bit smaller) than the eye of Sauron globe we saw a while back. We can’t wait to see a video of this thing in action once it’s completely finished!

Programming The Kinect To Work With Android

August 8, 2011 by 7 Comments

The Kinect has been hacked for many purposes, but this Android implementation tutorial is the first we’ve heard of it being used on a mobile phone platform. Although not a finished product at this point, [Raymond’s] tutorial is a good starting point for those wanting to experiment with fusing these two technologies.

The Kinect programming for this tutorial has been done with the Tegra Ventana development kit for Android 3.0. An Ubuntu-Linux installation is used, but this technique should be portable to any Linux system according to the author.

The procedure given is pretty straightforward, and the author even provides an example of the results in a video after the break. It’s interesting to note that, when connected, the Kinect is seen as two devices, “Xbox NUI Camera” and “Xbox NUI audio”. We look forward to new hacks to come out for this device, possibly using this set of tools. Continue reading “Programming The Kinect To Work With Android” →

3D Printed Turtle Shell Racers Bring Mario Kart To Life

August 8, 2011 by 13 Comments

skimbals_3d_printed_turtle_shell_racers

Every once in awhile a project comes along that makes us say, “this is why we want a 3D printer!”

[Skimbal] is pretty well known in 3D printing circles for the incredibly detailed designs he has put out in the past. This time around, his focus is on motoring, Mario Kart style.

His Turtle Shell Racers are ripped right out of the Mario Kart series of games, and are built in the form of the multi-colored turtle shells with which most of us have a love/hate relationship. Constructed atop cheap RC trucks, the Shell Racers require 20-some odd printed parts apiece, but looking at the final results we think the time and money spent would be well worth it.

After watching the videos below, we think you’ll agree that these things look like a blast to play with. The Shell Racers were actually so impressive that they managed to land [Skimbal] a permanent gig with MakerBot Industries.

If you want to try making a set of your own, there are extensively detailed build instructions and all the STL files you can shake a stick at over at Thingiverse.

Continue reading “3D Printed Turtle Shell Racers Bring Mario Kart To Life” →