LiPo Internal Resistance Measurement Tool

December 12, 2012 by 13 Comments

lipo-internal-resistance-meter

This is a scratch-build meter for measuring the internal resistance of Lithium Polymer cells. [Bleuer Csaba] uses the LiPo cells for RC vehicles and thet take quite a beating from the motors  they’re supplying. This means that he only gets about 100-200 cycles out of each cell. To figure out where one is in its life cycle you can measure the internal resistance where a rising resistance indicates greater age. [Bleuer] mentions that you can buy a meter to do this for you, but what fun is that?

Since he’s rolling his own tool he defined his own parameters for the readings. After experimenting with different loads driven for different test periods he was able to extrapolate an equation that estimates the resistance measurement. As you can see in the clip after the break, this happens very fast. All he has to do is connect the cell and press one button. The measurements are made and various data points are displayed on the quartet of 7-segment displays.

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Super Slim Wristwatch Build

December 12, 2012 by 33 Comments

super-slim-wristwatch-build

This slmwtch lives up to its name. When the LCD screen is folded back onto the PCB the entire thing comes in at just 2.35mm. That’s including a coin-cell battery not shown above. Wow!

Part of what makes this possible is the specialized PCB design. [Anders] didn’t want to add more thickness than the screen and battery so he make a cutout in the PCB design to accept each component. In this image it’s easiest to see on the two SMD resistor in the upper left. They’re held in a void by the two solder connections. Admittedly this is not going to be a mass-production friendly design. And we have concerts about the long-term stability of suspending components by their leads. But as a one-off it’s fantastic! See for yourself in the video after the break.

The control for the watch uses two touch sensitive pads on the back of the PCB. There is no backlight for the display which can be a problem when trying to read the time while outdoors. We wonder if an ePaper display with similar dimensions is available?

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Unlocking Verizon Galaxy Note II And Galaxy S3

December 12, 2012 by 13 Comments

galaxy-note-II-verizon-unlock

[Adam Outler] and friends have been hard at work unlocking the bootloader of some Verizon Android devices. His most recent adventure involves unlocking the Verizon branded Samsung Galaxy Note II.

You can’t run Cyanogenmod on a device that has a locked bootloader. This is presumably why it took no time at all for the XDA forum users with Verizon phones to raise enough money to put one of these puppies in [Adam’s] hands. He walks through the process he used to find the exploit in the video after the break. We’re not experts on the process, but apparently the .pit file used when flashing Odin is the entry point for the exploit. A bit of code has been injected into it which provides an opening to flash a replacement bootloader.

We mentioned the Galaxy S3 in the title. Apparently that has been unlocked as well but with one big hang-up. An over-the-air update could possibly brick the S3. To avoid this issue with the Galaxy Note II the original bootloader is patched and reflashed as part of the exploit.

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Observe A Satellite’s Morse Code Message Today!

December 12, 2012 by 58 Comments

Niwaka1-satellite

If you live in the Eastern portion of the United States and the skies are clear you can see a student built satellite flashing LEDs in Morse Code today. But don’t worry. If you it’s cloudy or if you live elsewhere there are several other opportunities to see it in the coming days.

This is the Niwaka Fitsat-1. It was developed by students at the [Fukuoka Institute of Technology] and deployed from the International Space Station on October 4th. Included in the payload is an array of LEDs seen in the image above. On a set schedule these are used to flash a Morse Code message for two minutes at a time. That is what’s shown in the image on the upper right.

You can look up information on seeing Fitsat-1 in your own area using this webpage. All of the observation windows in our area require a pair of binoculars or better. We’re not sure if there is any case in which this can be seen by the naked eye.

[Thanks SWHarden and KomradBob]

Tablet Rig Takes Sheet Music Digital

December 12, 2012 by 12 Comments

music-stand-tablet-holder

[Bill Dudley’s] wife wanted to use a couple of different tablets for displaying sheet music. Sure, a proper music stand will have no trouble supporting the weight of the device, but if it’s not secured it place you may soon have a broken device. [Bill’s] solution was to build this tablet stand out of PVC.

The image above doesn’t tell the entire story of how he did this. But if you look really closely you’ll notice that the pipe is actually acting as a frame rather than a cradle. After measuring, cutting, and gluing all of the components together he cut a channel around the inside of the u-shaped PVC frame. The channel is the exact thickness of the tablet and holds the device securely. A base from a music stand makes up the rest of the rig.

Pages can be turned using a USB foot pedal. This is fantastic for gigging musician who use digital music collections like the Real Book.

Raspberry Pi Hacking, Commando Style

December 12, 2012 by 36 Comments

raspberry-pi-and-notebook

If you’re lacking useful equipment for your Raspberry Pi hacking adventure, such as an HDMI monitor or power supply, this handy write-up will show you how to continue your hacking. All you’ll need is a laptop, the Raspberry Pi itself, an SD card, and an Ethernet and micro-USB cable. As noted in the article, it’s not really recommended to power the ‘Pi off of USB only, so this could potentially be a source of problems.

This hack begins by installing Linux on an SD card per this setup page, then using a Virtual Network Computing [VNC] setup to work with your Raspberry Pi. There are a few steps in between being able to do this, like setting up network sharing, and sleuthing out the IP address of the new processor, but everything is explained in detail for Mac and Linux. Windows users will have to do a bit of “sleuthing” of their own, but if you have some more information on this process, we’d love to hear about it in the comments!

Digital IR Theremin

December 12, 2012 by 6 Comments

Digital IR Theremin

This Digital IR Theremin creates tones based on the distance of an object from its IR sensor. There’s no microcontroller here, since the project is part of an Introduction to Digital Electronics course. Instead, it uses a handful of comparators, transistors, AND gates, and a 555 timer to make noise.

The comparators are connected to create window comparators. This configuration will output a digital 1 if the input is between two reference voltages, and 0 if it is not. Using this, the analog output of the IR range sensor can be converted to digital values.

The 555 timer takes care of creating the output waveform. A specific resistor is switched in to the timer’s RC circuit depending on which window comparator is active. This allows for a different tone to be played depending on the distance from the IR sensor.

The result is a square wave, which has a frequency dependant on how close an object is to the IR sensor. By selecting the right resistances for each distance, the theremin can be tuned to play a specific scale.

This is a neat project for people looking to learn digital electronics, and the write up does a great job of explaining the theory. After the break, check out a video of the theremin generating some tones.

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