Month: December 2013


A loudspeaker playing a clip of President Barack Obama talking about 3-D printing in his State of the Union speech might not seem so remarkable—except that the loudspeaker represents one of the first 3-D printed consumer electronic devices in the world.

The 3-D printed loudspeaker is more expensive, took longer to make, and is of a lower quality than a typical mass-produced speaker, said Hod Lipson, an associate professor of mechanical and aerospace engineering at Cornell University. But he described his lab’s demonstration to IEEE Spectrum as providing a “glimpse of the future” by showing that 3-D printing technology can eventually create all the necessary components of electronic devices:

“The real challenge is one of material science: Can we make a series of inks that can serve as conductors, semiconductors, sensors, actuators, and power. These inks have to have good performance and be mutually compatible. We’re not there yet, but I think its well within reach—we’ll see a variety of platforms well within the next 5 years.”

Most 3-D printers usually build objects layer-by-layer from a single “passive” material such as plastic. But researchers have been testing how to use 3-D printing to squirt out conductive inks that can form the building blocks of integrated systems such as electronic devices.

The Cornell project—headed by mechanical engineering graduate students Apoorva Kiran and Robert MacCurdy—used two of the lab’s homegrown Fab@Home printers to create the 3-D printed loudspeaker parts. One printer made the plastic cone and base of the loudspeaker. The second printer laid down the wires on the cone and created a magnet inside the plastic base. (The team swapped out the second printer’s ink cartridge from conductor to magnet ink between printing runs.)

Silver ink provided the conductive material for the wire. For the magnet, Kiran enlisted the help of Samanvaya Srivastava, a graduate student in chemical and biomolecular engineering, to develop a strontium ferrite blend. Two Cornell undergraduates, Jeremy Blum and Elise Yang, also worked on the project.

The 3-D printed loudspeaker didn’t come out all in one piece—researchers manually moved the parts between the two printers and then snapped the cone and base together to complete the device. But Lipson says the complete loudspeaker could be printed on a single 3-D printer if the printer had multiple deposition tools capable of squirting out the different materials needed for the plastic, wires and magnet. Such printers could already be developed within labs in a month or so from a technical standpoint, but thebusiness demand is not there yet with 3-D printed electronics still in their infancy.

Lipson previously worked with former Cornell graduate students, Evan Malone and Matthew Alonso, to create a 3-D printed version of a working telegraph modeled on the Vail Register—the famous machine that Samuel Morse and Alfred Vail used to send the first Morse code telegraph in 1844. By comparison, the 3-D printed loudspeaker represents a relatively modern example of a commercial electronic device.

Once 3-D printing gets the hang of making electromagnetic systems, the technology could open the door for new customizable shapes and optimized performance for specific electronic devices—features that mass manufacturing can’t offer. Lipson described the idea of creating 3-D printed headsets, microphones, and other devices custom-made.

Eventually, 3-D printing could also revolutionize the manufacturing of robots. Lipson’s lab envisions using 3-D printers to build robots with “embedded wires and batteries shaped like limbs,” as well as all the other necessary components of robotic technology.

“We hope to be able to develop working electromagnetic motors in the future which would be the cornerstone upon which printed robots could be built,” said Robert MacCurdy, one of the Cornell graduate students heading the 3-D printed speaker project.


One day in 1994, seven world-leading technology companies sat down and created a new standard for connecting computer peripherals. By “one day,” of course I mean, “over the span of several months.” But all technicalities aside, the standard that they laid down became the Universal Serial Bus, or USB for short.

Today, USB is truly a ‘Universal’ standard and you’d be hard-pressed to find an electronic device that doesn’t have a USB port of one kind or another. But how do you know which USB cable will fit your device? Hopefully this buying guide will help you find the cable that you need for your next project.

What Does USB Do?

USB cables replace the huge variety of connectors that used to be standard for computer peripherals: Parallel ports, DB9 Serial, keyboard and mouse ports, joystick and midi ports… Really, it was getting out of hand. USB simplifies the process of installing and replacing hardware by making all communications adhere to a serial standard which takes place on a twisted pair data cable and identifies the device that’s connected. When you add the power and ground connections, you’re left with a simple 4-conductor cable that’s inexpensive to make and easy to stow.

500px-USB_half Continue reading


We had earlier in 2 different posts discussed about a variable power supply using LM 317. But in this post we discuss clearly about the working and designing of the LM 317 power supply in detailed.

Block Diagram

This circuit, like all voltage regulators  must  follow the same general block diagram


Here, we have got an input high voltage AC going into a transformer which usually steps down the high voltage AC from mains to low voltage AC required for our application. The following bridge rectifier and a smoothing capacitor to convert AC voltage into unregulated DC voltage. But this voltage will change according to varying load and input stability. This unregulated DC voltage is fed into a voltage regulator which will keep a constant output voltage and suppresses unregulated voltage ripples. Now this voltage can be fed into our load.

Firstly let us discuss about the need for the smoothing capacitance.As you know  the out put of the bridge rectifier will be as follows


As you can see, although the waveform can be considered to be a DC voltage since the output polarity does not invert itself, the large ripples Continue reading



In a masterful publicity stunt, Amazon CEO Jeff Bezos announced on 60 Minutes — on the night before Cyber Monday — that his company has been working on a drone service that will deliver items under 5 pounds, and within ten miles of an Amazon fulfillment center, in under 30 minutes..

This is definitely exciting, but exactly how much does Amazon have to accomplish between now and Jeff’s launch goal of 2015? Getting the FAA onboard will be hard enough, but what about actually getting shipments out safely, when that time finally comes? Is this even possible, or simply a publicity stunt by the e-commerce giant? They’re definitely not the first to think about doing this. Matternet has been working on bringing drone-supported shipping to areas of the world where roads aren’t common, or structurally sound enough, to handle everyday deliveries. CEO Andreas Raptopoulos talked about his vision at May’s Hardware Innovation Workshop.

If Amazon is really going for it, here are the main challenges and some of my thoughts on how Amazon will handle them:


Probably the easiest to deal with. Amazon says they’re shooting for 30 minute deliveries, which I’m assuming means 30 minutes from take-off to landing, not order to landing. Jeff says they will deliver to within 10 miles of an Amazon Fulfillment Center, which is doable if the octocopter can go at least 20mph. The challenge here is giving them enough battery power to survive the trip to the customer and back home. Carrying that much weight at that speed for up to an hour is going to require some heavy batteries. Continue reading


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