Year: 2011

14-part RepRap Saga Draws To A Close

October 21, 2011 by 17 Comments

Behold, another RepRap springs into existence! Well, springs might not be the best choice of words, it took a while and there were many bumps in the road. But [NBitWonder’s] self-built RepRap is now finished and you can read his 14-part build log to see all that went into the process.

We checked in on the project at one of the early stages. At that point he was just beginning to assemble the hardware and we mused that the calibration stage is where we thought things would get exciting. The project didn’t disappoint, as he had many follies getting the extruder heads to work. At first some issues popped up when figuring out what diameter filament would work for the print head he was using. Once that was worked out, a less-than-precise PID controller led to the clogging and eventual destruction of the extruder tip. He goes on to assemble and test a heated build platform only to discover that the resistors shipped with the hardware are shockingly underrated for the task. We could go on and on, but that would ruin the fun for you. Bookmark this one for the weekend and enjoy!

Extend Your Personal Weather Station’s Reporting Capabilities

October 21, 2011 by 3 Comments

This Nexus wireless weather station has an array of weather sensors that you mount outside and monitor on the LCD screen. It also has the ability to stream the data over USB, but that feature is only supported in Windows and the companion software leaves a lot to be desired. Here’s a technique that will let you unlock the potential of the data by streaming it to your Linux box or directly to the Internet.

It turns out that grabbing the data via Linux has been made quite easy thanks to a package called TE923 (translated). With the base unit connected via USB, the software will pull down a string of colon-separated data which will be easy to parse using your favorite scripting language. But what if you don’t want to tether this to a computer?

The project goes one step further by using a Carambola board. This is a WiFi board with a USB port on it. It runs OpenWRT so getting TE923 going is as simple as building the package. The best part is, any wireless router that runs OpenWRT (or DD-WRT, etc.) and has a USB port can substitute for this board. With the module connected to the station, data is pushed to the Pachube website to serve as a custom web readout.

[Thanks Saulius]

Building Optical Flex Sensors

October 21, 2011 by 12 Comments

[Joel] dug up this hack that he pulled off over ten years ago. It’s inspired by the Nintendo PowerGlove, and uses flex sensors to react to movements of your fingers. The interesting thing is, he built these optical flex sensors himself.

He likes to say that this is a ghetto fiber-optic setup. The inlaid diagram above gives you an idea of how the sensors work. An IR LED and infrared diode are positioned at either end of a piece of clear aquarium tubing. When the tube is flexed, the amount of light that makes it to the diode is diminished, a change that can be measured by a microcontroller. [Joel] found that he could increase the resolution of the sensor by adding something to the center of the tube, blocking the light when not straight. In this case he used pieces of scrap wire. The outside of the sensor was also wrapped in shrink tubing to keep ambient light from interfering with measurements.

He uses a trimpot to tune the sensors but we wonder how hard it would be to add a calibration algorithm to the firmware?

Illogical Voltage Double Uses Logic

October 21, 2011 by 5 Comments

[Jonathan Thomson] just finished writing up his entry for the 7400 logic contest. It’s a voltage doubler that uses a 74HC14 logic chip. Because this is not at all what the chip was meant for–and he’s a sucker for puns–he’s calling it the Illogical Dickson Doubler.

What he’s got here is basically a charge pump built from a set of diodes and capacitors. On the breadboard you see two chips, one is used as a clock signal generator for the other which is acting as part of the charge pump. We’ve seen a string of hacks that misuse the protection diodes on the inputs of logic chips. In fact, [Jonathan’s] setup uses the same back power concept that barebones PIC RFID tag did. You may remember in that project the chip was being powered from one of the I/O pins, with the VCC pin not connected to anything.

We’ve embedded a video after the break with shows some voltage measurements, as well as an LED being powered from the doubling circuit.

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Light Painting Nyan Cat With An Arduino

October 21, 2011 by 5 Comments

You too can paint your favorite meme in light with just a few tools. [Skywodd] brought together a couple of different projects to make this happen. He had already built a large POV display and now uses a DSLR with long exposure to create light paintings (translated).

The Arduino-powered display is built from a strip of 35 RGB LEDs. Now, that’s four pins per LED but one of is ground, leaving just 105 pins that need to be addressable. A couple of things make this manageable. First, he etched his own circuit boards for the LED strips. This breaks out the contacts to the edge of the boards and simplifies the soldering a bit by taking care of the ground bus. Secondly, he’s using M5450 LED display drivers for addressing. After the break you can see the video of the prototype hardware (in French but blinky action starts at about 2:30).

If you’re looking for an easier way to do this, check out the light painting that uses manufactured LED strips.

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Cheap Acoustic Panel DIY

October 21, 2011 by 37 Comments

[Eric Wolfram] wrote in to let us know about a simple and cheap acoustic panel DIY he put together.  When installing a home theater acoustics are often neglected (especially if you spend so much on the TV you cannot afford any furniture for the room) resulting in reduced listening quality and poor spacial sound imaging from your surround system (also responsible for the furniture problem). The addition of sound absorbing panels helps control the acoustics of the room and may even class up the place a bit.  These are also come in handy for home studio usage where a low level of reverberation is preferred.

The panels are relatively simple to produce on a budget, just a sheet of 2″ thick dense fiberglass board glued into a wooden frame and covered in a sound-transparent fabric. [Eric] goes into a lot of the material selection process to help you along your way. The best part about the project (aside from its obvious utility) is that all of the materials can be found cheaply at your average home improvement store, with the exception of the fabric.  [Eric] mentions that you can substitute colored burlap if need be.  Once the panel is assembled and glued it just has to be hung on the wall of your choice like a large heavy picture frame. This could certainly help the acoustics and reduce some slap-back echo in your warehouse/shop. We might have to try this one over the weekend.

Thanks [Eric]!

A Very Simple Android Recon Vehicle

October 21, 2011 by 13 Comments

Desperately in need of a graduation paper, [Andrei] decided to build a few computer controlled recon vehicles (PDF warning), and we’re really impressed with the minimalist approach [Andrei] took.

The Computer Operated Recon Entity (C.O.R.E.) mk. I is based around a laptop. Instead of an Arduino, [Andrei] used a car stereo amp to control the motors. The two channel amp [Andrei] picked out has four outputs. Tying a motor to each output gives a four-wheel drive robot that’s really clever in its simplicity. With an onboard webcam, [Andrei] can do live video streaming from his remote vehicle. Outputting a specific tone with the sound card allows for full control of the robot.

The C.O.R.E. mk. II uses a Samsung Galaxy I5500 phone – the cheapest Android phone [Andrei] could find. The setup is similar to the mk. I C.O.R.E. with a WiFi connection sending video back to a base station. Control of the two motors is still handled by playing sound files and sending that to a stereo amp connected to the motors.

Check out the C.O.R.E. mk. II going Bach and forth after the break.

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