Solar Charge Controller Improves Efficiency Of Solar Panels

March 17, 2015 by Bryan Cockfield 54 Comments

The simplest and easiest way to charge a battery with a solar panel is to connect the panel directly to the battery. Assuming the panel has a diode to prevent energy from flowing through it from the battery when there’s no sunlight. This is fairly common but not very efficient. [Debasish Dutta] has built a charge controller that addresses the inefficiencies of such a system though, and was able to implement maximum power point tracking using an Arduino.

Maximum power point tracking (MPPT) is a method that uses PWM and a special DC-DC converter to match the impedance of the solar panel to the battery. This means that more energy can be harvested from the panel than would otherwise be available. The circuit is placed in between the panel and the battery and regulates the output voltage of the panel so it matches the voltage on the battery more closely. [Debasish] reports that an efficiency gain of 30-40% can be made with this particular design.

This device has a few bells and whistles as well, including the ability to log data over WiFi, an LCD display to report the status of the panel, battery, and controller, and can charge USB devices. This would be a great addition to any solar installation, especially if you’ve built one into your truck.

This is [Debasish]’s second entry to The Hackaday Prize. We covered his first one a few days ago. That means only one thing: start a project and start documenting it on hackaday.io

Brighten Your Day With Motion Controlled Cabinet Light

March 16, 2015 by Will Sweatman 23 Comments

[Thomas Snow] found himself in a bit of a pickle. His kitchen lights didn’t adequately light his counter-tops. So instead of inventing a light bending device that could warp space-time enough to get the light where it needs to go, he decided to take the easy road and installed a motion controlled LED strip under the cabinets.

Now, these aren’t just any ‘ol motion control lights. Not only is [Thomas] able to turn the lights on and off with a wave of his hand, he can control the brightness as well. He’s doing the magic with an ultrasonic range sensor and PIR sensor. An ATTiny85 ties everything together to form the completed system.

The PIR sensor was incorporated because [Thomas] didn’t want to bug his pets with the 40kHz chirp from the ultrasonic sensor. So it only comes on when the PIR sensor sees your hand. Be sure to check out [Thomas’s] project for full source and schematics.

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Mobile Lorm Glove Puts Texting Back Into Everyone’s Hands

March 16, 2015 by Sonya Vasquez 2 Comments

If you’ve been killing time texting or chatting with your pals via smart phone, odds are pretty good that you’re not giving much thought to the two senses that make it happen: your sight and your hearing. Those who are deafblind, however, cannot participate in these activities; and for many, the remote communication that most of us enjoy with our phones simply isn’t possible. Enter Berlin University of the Arts Design Research Lab. Here, they’ve developed the Mobile Lorm Glove, a haptics device that enables two-way remote communication via smart phone.

For the deafblind, Lorm is the tactile technique for communication. Lorm is a series of hand-tracing gestures that map to characters of the alphabet. To communicate with others, the gloved user can trace Lorm directly onto the pressure-sensitive inputs on the palm of the hand. To receive messages, small vibration motors on the back of the hand vibrate to indicate the message encoded in Lorm.

Originally, to communicate with the deafblind, we must first learn Lorm. With the Mobile Lorm Glove, however, we need only know how to send text messages, and the Lorm-decoding is handled with a look-up table running on our classic Atmega328 microcontroller. For the sharp-eyed, the back-side of the glove seems limited in its capability to transcribe continuous finger traces into discrete motor vibrations. However, with four shift-registers and 32 levels of motor-intensities, the designers address each motor with a technique called “funneling illusion” where continuous movement is simulated by gradually changing the intensity from motor to motor. For more tricks and details, take a look at their conference paper.

By wearing the glove, everyday communication can be made far easier with anyone with a smart phone. We’re jazzed that just a Bluetooth module, an Atmega328, and a collection of pressure sensors and motors can enable any cell phone user to circumvent the learning curve and open up a new conversation.

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Microscope Camera For Zeroing CNC Machines

March 16, 2015 by Brian Benchoff 16 Comments

After what we’re sure is several dozen screw-ups or at the very least a lot of wasted hours, [Chris] has gotten around to building a very precise microscope camera mount for zeroing out his CNC machine.

If you need to mill a few bits out of a sheet of metal or plastic, it’s important to know exactly where you’re cutting. A CNC machine can take care of the relative positioning, but if you already have half your holes drilled, you also need absolute positioning. This means placing the work piece exactly where you want to cut, or failing that, zeroing the machine to a predefined point on the piece.

[Chris] is accomplishing this with a pen-shaped USB microscope. With a 3D printed mount and a few magnets, this camera can clip right on to the machine, and with the camera interface in Mach3, it’s pretty easy to zero out the mill to within a thousandth of an inch.

There’s a video demo of the camera in action below, but there’s a lot more CNC mods on [Chris]’ website. There’s custom 3D printed vacuum nozzles, and a lot of work on a small desktop Grizzly mill.

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A Motor, An Arduino And A Whole Bunch Of Laser Cutting

March 16, 2015 by James Hobson 14 Comments

[Guido] was recently commissioned to build a kinetic sculpture for a client who wanted something unique. What he came up with is really awesome.

It’s called ORBIS: The Wooden Kinetic & Lighting Sculpture. It mounts to the wall and provides a focal point for the room – a bright flashy spinning one at that! Does it just stay there and do random things? Nope, of course not! [Guido] built it with a unique control box, two Arduino 2560’s and an Xbee to communicate between them.

He was told to design it using old and new technologies so he’s got a rotary phone dial on the side of the box which allows the user to change through the different modes.

Switches on top also let you change the color of the sculpture and the speed at which it moves around. Since it’s wireless it can be easily set on the coffee table and become an instant conversation starter.

See it in action after the break.

Continue reading “A Motor, An Arduino And A Whole Bunch Of Laser Cutting” →

Beating DRM To Extend The Life Of An Anti-Aging Therapy Light Mask

March 16, 2015 by Anool Mahidharia 89 Comments

It’s becoming more common to see DRM cropping up in an increasing number of hardware products nowadays. Quite often, its used to prevent the use of unauthorized consumables and some may argue that it helps prevent counterfeiting and help shore up revenues. But it’s a totally different matter when DRM is used to severely limit the operational life of a product. When [travis] wrote in about the run time limitation on an “Illumimask” light therapy device, we first had to look up what that device was. Apparently, these are anti-acne or anti-aging light therapy masks that use red and blue LEDs to kill skin bacteria, stimulate skin cells and reduce blemishes. While these claims most likely may not hold water, the device itself is cheap enough not to hurt you at $30 a pop.

The trouble is, it is limited to 30 daily uses of 15 minutes each, totaling just 7 1/2 hours, effectively lasting you a month. At the end of which, you just discard the device and get a new one. That seems like a ridiculous waste of a perfectly fine, functional device whose LED’s can last at least 30,000 to 40,000 hours. [travis]’s wife [Bebefuzz] was obviously pissed at this situation. So she did a simple hack to bypass the microcontroller that imposed the goofy restrictions. In [travis]’s own words “Not a crazy-technical hack…. but a very functional one to bypass a manufacturer’s ‘WTF'”. It involved soldering a slide switch across the circuit terminals that the micro-controller uses to monitor the LED current (likely). Unfortunately, this also breaks the 15 minute timer measurement, so she now has to manually switch off the device at the end of the 15 minute therapy cycle.

To check out more DRM hacks, check out these we covered earlier, from Coffee Makers to 3D printer filaments to Cat Litter boxes and even furniture.

Instrumentation Amplifiers with Bil Herd

Instrumentation Amplifiers And How To Measure Miniscule Change

March 16, 2015 by Bil Herd 60 Comments

These days there a large number of sensors and analog circuits that are “controller friendly” meaning that their output signal is easily interfaced to the built-in Analog to Digital Convertors (ADCs) often found in today’s micro-controllers. This means that the signals typically are already amplified, often filtered, and corrected for offset and linearity. But when faced with very low level signals, or signals buried in a larger signal an Instrumentation Amplifier may be what’s needed. The qualities of an Instrumentation Amplifier include:

A differential amplifier with high impedance and low bias current on both inputs.
Low noise and low drift when amplifying very small signals.
The ability to reject a voltage that is present on both inputs, referred to as Common Mode Rejection Ratio (CMRR)