Revive Old Drive-In Speakers with a Modern LED Twist

When I was a kid we went to the drive-in theater to see movies like The Legend of Boggy Creek and Evel Knievel. I loved those movies but I remember just as vividly those retro-cool metal speakers that entered into our car for these campy films. A few years ago I found one of these speakers at a flea market and it came home with me. After it sat in my garage for years, I finally decided it needed to be what ...

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Guidelines for reading an optocoupler datasheet

Optocouplers, also known as opto-isolators, are components that transfer electrical signals between two isolated circuits by using infrared light. As an isolator, an optocoupler can prevent high voltages from affecting the side of the circuit receiving the signal. Transferring signals over a light barrier by using an infrared light-emitting diode and a light-sensitive product, such as a phototransistor, is ...

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Build a Simple Cocktail Drinkbot with Arduino

Big parties need a conversation piece, and what’s better than a drink-making robot? Not only is it a good conversation starter, it also frees up the party host who would normally be the bartender. It turned out that the drink robot was a really good idea. The Mai Tai recipe presented here has the alcohol dialed back making it a good idea for a work party. The robot is really an Arduino microprocessor (Uno v ...

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Major step for implantable drug-delivery device

An implantable, microchip-based device may soon replace the injections and pills now needed to treat chronic diseases: Earlier this month, MIT spinout Microchips Biotech partnered with a pharmaceutical giant to commercialize its wirelessly controlled, implantable, microchip-based devices that store and release drugs inside the body over many years. Invented by Microchips Biotech co-founders Michael Cima, th ...

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Extract DNA at Home with a 3D Printed Centrifuge

Biotechnology is powerful, but only for those with the tools to experiment with and utilize it. The DIYbio movement seeks to put the tools and techniques used in well-funded laboratories around the world into the hands of ordinary people who have an interest but not the means to investigate biology. One of these tools is the centrifuge. Centrifuges come in many shapes and sizes to fit a wide variety of labo ...

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The Best NiMh Charger (for now)

It's been a long time since I posted an update on my battery charger project (in fact it has been a long time since I have posted anything!).  I have been Very Busy with projects for my work and when I am not working for work, I am working on battery chargers.  When I am not working on battery chargers I am trying to be a good husband and father as well as find time to do things like mow the lawn or fix the ...

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A Simple Arduino LCD Min/Max Thermometer

As a simple first Arduino experiment I interfaced a two line LCD (a Displaytech 162B) and an LM35DZ to make a simple Min/Max thermometer. Step 1 - Interfacing the Temperature Sensor This is really very simple. The LM35DZ has three pins, +5V, ground and a variable voltage output to indicate the temperature. I plugged it into breadboard and wired the output straight to the Arduino's analogue input 0. To test ...

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Digital Door Lock using Arduino

As thefts are increasing day by day security is becoming a major concern nowadays. In this project we will make a digital door lock system with keypad using Arduino Uno. It will open your door only when the right password is entered and it will start beeping when a wrong password is entered. Components Required 4×4 keypad LCD Arduino Uno Push Pull Solenoid TIP 120 NPN transistor Power Supply Breadboard 1KΩ, ...

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Arduino DCF77 Master Wall Clock

Arduino Master Wall Clock. Time displayed on large 1" (26mm) 7 segment displays with secondary 4x20 LCD information display. The clock can be used stand alone or provides the following pulses to drive slave clocks 1 sec alternating, 30 sec, 1 min , 1 hour, 24 hr, 15 min chime of quarter hours, hourly chime of hours. An Arduino 328 Microprocessor is used to decode and display time & date from the DCF77 " ...

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Home Automation using Arduino and ESP8266 Module

In this project we are going to make a home automation system using ESP8266 WiFi module and Arduino Uno. Using this we will be able to control lights, electric fan and other home appliances through a web browser using your PC or mobile. These AC mains appliances will be connected to relays which are controlled by the Arduino. ESP8266 and Arduino together acts as a Web Server and we will send control command ...

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Designing a PIC24 Development Board

Several of our recent projects have used a 16 bit PIC24 microcontroller from Microchip.  The PIC24FJ128GC006 contains two 16-bit ADC channels which makes it useful for measuring voltages more accurately than the 10 or 12 bit ADCs you normally find on microcontrollers.  We used this microcontroller for the temperature controller on our recent Soldering Robot and are looking at using it for another project in ...

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Samsung Researchers Nearly Double Lithium-ion Battery Capacity

A low-magnification tunneling electron microscope (TEM) image of Gr–Si nanoparticle (NP). (b) A higher-magnification image for the same Gr–Si NP from the white box in a. (Insets) The line profiles from the two red boxes indicate that the interlayer spacing between graphene layers is ~3.4 Å, in good agreement with that of typical graphene layers based on van der Waals interaction. (c) A high-magnification TE ...

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