Science Projects

This lantern was built from recyclable goods. It’s a bit dangerous when used like the image above, but [The Green Gentleman] does give you a few other options in his build instructions which make for much safer operation. The lantern enclosure is made from old cans and a glass jar. He screwed a couple of boards together at a right angle to act as a jig for cutting the glass. The V-shape created by the boards holds the jar on its side, giving his glass cutting tool something to rest upon. He then turns the jar to score it around the top, and then bottom. He alternated pouring boiling and chilled water on the score mark to shock the glass into breaking along the line. This makes up the clear part of the enclosure which is later mated with metal top and bottom pieces. From there he adds either an LED, an alcohol lamp, or the Trimethyl Borate lamp seen above. The first two are relatively safe, but the latter burns at around 1500 degrees F. We have reservations about using a plain old glass jar as the enclosure for something burning this hot. It really should be heat resistant glass. Filed under: chemistry hacks

On Sunday, May 26th, a very special sunset will take place. Three planets – Venus, Jupiter and Mercury will form a triangle in the night sky. They will all be visible to the naked eye or seen together in a binocular field. Courtesy Science.NASA.gov This is a fairly rare celestial event. The last time it happened was in May 2011 and the next time the planets will form a geometric shape will be in October 2015. The three planets are the brightest in the sky. Venus is #1, followed by Jupiter #2 and Mercury #3. Their triangle will be visible even in urban areas with lots of lights. Courtesy Science.NASA.gov To find the trio, look about 30 to 60 minutes after sunset at the western horizon. Venus will be the brightest and lowest with Mercury to the right and Jupiter to the upper left corner. The planets are visible now through early June, with May 26th being the optimal time to spot the triangle. On May 23rd, Jupiter and Venus will be close enough to spot together in binoculars. On May 24th, Mercury will pass by Venus with less than 2 degrees of separation. On May 28th, Venus and Jupiter will pass with 1 degree of distance. Jupiter’s four largest moons can be seen with strong, steady binoculars or a backyard telescope. Don’t forget to also look for Saturn. It will have a golden hue and be in the south sky to the east of the moon. The star Spica will also be visible near Saturn and the moon. Spica sparkles blue-white and is the brightest star in the Virgo constellation. Information courtesy Science.NASA.gov. More skywatching tips and events from EarthSky.org.

[Chonggang Li] wrote in to share a link to the final project he and [Ran Hu] built for their embedded systems class. It’s called Piano Hero and uses an FPGA to implement a camera-based touch screen system. All of the hardware used in the project is shown above. The monitor acts as the keyboard, using an image produced by the FPGA board to mark the locations of each virtual key. It uses a regular VGA monitor so they needed to find some way to monitor touch inputs. The solution uses a camera mounted above the screen at an obtuse angle. That is to say, the screen is tilted back just a bit which allows the images on it to be seen by the camera. The FPGA board processes the incoming image, registering a key press when your finger passes between the monitor and the camera. This technique limits the input to just a single row of keys. This should be much simpler than using a CCD scanner sensor, but that one can track two-dimensions of touch input. Filed under: multitouch hacks

[Kees] wanted a remote for an XBMC audio system. He had a classic T65 Dutch telephone in one of his project boxes and thought this phone with the addition of a Raspberry Pi he could have a functional media remote with classic lines and 70s styling. Each of the digits on the phone were wired up to a small solderless breadboard. With a handful of resistors, [Kees] set up a simple pull up/pull down circuit feeding in to his Raspi’s GPIO input. With a short Python script, [Kees] managed to map the buttons to XMBC’s play/pause, volume up/down, next, and previous commands. There were a few buttons left over, so those were mapped to online radio stations, playlists, and a strange setting known only as ‘moo’. We’re not sure what that button does, but you can see the other functions of this XMBC phone remote in action in the video below. Filed under: phone hacks, Raspberry Pi

Check out Microphone Driven LED Heart: Blooper Reel by getupgetdowning a short 6 second film for the Adafruit #adafruit6secs electronic film festival (Youtube playlist here for all the entries on YouTube).

A submission from the Adafruit 6 second electronics film festival explained: You’re looking at ~24 hours of continuous AVR flashing compressed down into 6 seconds. While I won’t be releasing the connecting PCB just yet (i’m still beating down a few issues and refining the BOM), I thought it would be good to supply the scripts I used to do the actual time lapse since it was non-obvious from a “oh dear, the contest entry is due in Source code and more here!

Once upon a time, a nerd met a girl. Things happen as they do, and eventually [Ben] wanted to create the be-all, end-all engagement ring. It’s a simple titanium affair with 23 stones around the perimeter. What makes this ring so cool, though, is that it lights up whenever [Ben] and his girl are holding hands. The metalworking portion of the build was about as easy as you would expect machining titanium to be. After the ring was cut off its bar stock, [Ben] brought it over to a mill where 23 holes for each of the stones were drilled. The stones were affixed to the ring with  jewelers epoxy and the entire ring was buffed to an amazing shine. The electronics are where this project really shines. Putting a battery of capacitor inside a ring is nigh impossible, so [Ben] decided to power the LEDs with an inductive charging circuit. A coil of wire wound around kapton tape serves as the inductor and a small SMD capacitor powers three very bright and very tiny LEDs. The inductive charging unit itself is a masterpiece of hackery; [Ben] wanted the ring to light up whenever he and his ladyfriend were holding hands. To do this, [Ben]‘s inductive charger is also a wearable device: a large coil of wire is the charger’s transformer and was would to fit around [Ben]‘s wrist. The entire charging circuit can be easily hidden under a jacket sleeve, making for a nearly magical light-up ring. An awesome piece of work, and one of the best jewelry builds we’ve seen in a long time. You can see the inductive coupling and shining LEDs in the video below. Filed under: led hacks, wearable hacks

Thermoelectric devices are seen very often in various appliances. Small refrigerators, semiconductor chip coolers, medical chillers. Thermoelectric effect works in both directions – it can generate temperature difference when current flows or it can generate current when temperature difference is applied. About thermoelectric effect It is known for more than 100 years. There are several scientists who discovered this effect in one or another way. Probably you’ve heard Peltier effect. Jean Charles Athanase Peltier discovered that if you apply electrical current to junction of two materials it gets cold or hot (depending on current direction). The reverse effect when electricity is generated due to temperature difference was discovered by Thomas Johann Seebeck. So this effect is Honored by his name. But for now lets focus on Peltier effect and thermoelectric devices. Peltier element The most common element is ceramic coated device with two wires popping out. They are made of semiconductor materials. One is N type and another is P. Instead of single Junction there are hundreds of them – simply speaking they are connected in series, but thermally they are parallel. Multiple joints increases the surface are and so the efficiency. If you look inside the Peltier element you will see a sandwich made of small silicon bricks electrically connected in series. The ceramic plate is used as carrier and heat transferee. Each individual pair works same way, the heat is absorbed from one side of plate and transferred to another. If we go deeper in to working physics we can see that when current flows electrons in N-element are pushed against the current while holes in P element same direction as current. Both are mowing from one side of element absorbing heat. The heat is carried to another junction. Hope this is enough for understanding what happens there. And again. If we apply different temperatures to both sides of plates we get electricity (Seebeck effect). It is not common usage as it’s efficiency is very low. Some space programs have been using those as alternative energy source. So why thermoelectric coolers aren’t used widespread? It seems that they are beneficial in many ways including solidness (no moving parts), failure proof if used correctly and are easy to control. It appears that they aren’t as efficient we would like it to be. Compressor based systems are several times more efficient which keeps them in refrigerator business. Peltier elements can reach temperature difference between surface to about 70ºC. The bigger difference is the worse efficiency becomes. So it is used in compact coolers, in environmental friendly applications where efficiency isn’t the key. You’ve probably seen an USB powered cooler for soda cans – it wouldn’t be possible without thermoelectric coolers. Peltier elements are pretty standardized devices and you can tell some features from its ID. For instance I have couple of TEC1-12705 elements what can be decoded in to; TE – thermoelectric; C – size. C – standard; S – small; 1 – number of stages. Normally 1. 127 – the number of P-N couples inside the plate; 05 – current rating. In this case 5A. As all semiconductors it is sensitive to overheating. It is advised not to power Thermoelectric element without heat-sink on hot side. Probably you can connect it for a short time to determine which side cools and which heats. Typical cooler application If you are going to build a cooler, your typical setup should be as follows: It is mandatory to put a heat-sink on a hot side of Peltier element which would take a transferred heat. For better transfer put thermal paste. It is good idea to have temperature sensor on heat-sink in order to avoid overheating. On cold side of plate you can put what ever you designed – a cold plate, another heat-sink with blower to get cool air or what ever you need. Here also you can put a temperature sensor to keep cold point. If hot heat-

A spaceship simulator sounds fun. But a spaceship disaster simulator is pure win. Members of the LHS Bikeshed hackerspace over in the United Kingdom poured their hearts and souls into this build. Now they’re taking the show on the road, letting attendees of Maker Faires all over the UK try their hand at beating the Kobayashi Maru disaster simulation. The real question is how do you take your simulator on the road with you? You build it in an old camper (or caravan as the Brits call it). The towable sleeping quarters were gutted to make room for the well-crafted command center seen above. The demonstration video also shows off some bulkhead doors which open to reveal a wiring mess that must be fixed to prevent a disaster. Not only does the physical build really sell the concept, but the audio and video produced for the simulator look fantastic too. The link above is a recent post, but you should dig through their archives see multiple steps during the project build. It makes us thing we should keep going with our VW Bus hacking. Filed under: Hackerspaces

N9 Satellite Dish Control. Travis writes - Here, my Nokia N9 in Europe is commanding my satellite dish in America. Clicking on a target physically moves the dish to aim in the appropriate direction, readjusting as the target moves in the sky.