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7 Apr 2014

raspberrypi-model-b

lightnin9 @ instructables.com writes:

Now everybody knows it’s way smarter to just pay someone to host your website. But what not everybody knows is that it’s way more punk rock to Do it Yourself. So what follows are some tips / pointers / instructions for setting up your own home webserver (which will burn a scant 2 watts) using all free, open source software, a Raspberry Pi, and your home internet connection.

The emphasis here is on lightweight, which fits well with the Raspberry Pi. Sure, you can setup a blog with wordpress or Django, and they will run (I’ve tried it, at least with Django). But they probably will run rather slowly. Why? The rPi doesn’t have a lot of memory or processing power, and a database / front end model requires a decent amount of that. If your site / blog ever gets much traffic, it’ll likely buckle under the load. The answer? Just serve up plain old static HTML pages. It’s fast, secure, simple, and easy on the rPi’s limited resources. But rather than painstakingly handcodeing each new blog entry, you can use a static html generator like Pelican to make it easy.

Host your own blog from a $25 Raspberry Pi computer - [Link]

7 Apr 2014

DSC00719r2

Martin Thomas shows us how to interface Atmel AVR witg graphic LCDs:

This is a C-library for avr-gcc/avr-libc to access SED1520-based graphics-LCDs. The modules used to develop the library only support “write to LCD”, read-modify- write on the display RAM is not possible. So this Library uses a “framebuffer” which holds the display-content in the AVR’s SRAM. For a 122*32 pixel display around 500 Bytes of SRAM are occupied by the buffer. The library does of cause support modules which can be read in “write-only-mode” (tie the R/W-Pin to GND).

Interfacing Atmel AVR with Graphics Liquid Crystal Displays (GLCDs) - [Link]

7 Apr 2014

This GU10 LED spot light is cheap (£3 including postage) and bright. But it’s also lethal! There’s a 50% chance of putting live mains within a few microns of the metal casing (which is what you’ll be holding when you insert it) and there’s no earth to protect you. It’s like playing Russian Roulette with 240v AC mains. This sort of thing gives new technology a bad name. Avoid it if you want to stay alive.

Dangerous GU10 LED Spot Light is Cheap and Bright but could Kill You – Seriously - [Link]

7 Apr 2014

DI5452f1

by Viktor Safronov:

Sometimes you may need a group of switches where, if any switch is activated, it deactivates the previously active switch. This Design Idea implements such a function with relays.

This “one and only one” function is often implemented as mechanical switches in which an actuator (usually a movable metal bracket) is used to switch contact groups on and off. When any switch is pressed, this bracket first deactivates all switches, then activates the pressed switch.

Exclusively select 1 of N relays - [Link]


6 Apr 2014

An Arduino-compatible smart outlet designed to instantly turn your toaster oven into a reflow soldering station.

Advances in technology continue to shrink the size of components. Hobbyists, who have traditionally worked with through-hole parts, are finding these parts harder and harder to come by as more parts become unavailable in through-hole variants.

Soldering surface mount components with a soldering iron, while possible, can be a rather tedious task. In particular, when you’re working with densely packed pins like those of a microcontroller, hand soldering a board quickly becomes a daunting task.

Reflowster – Soldering Controller for Surface Mount PCBs - [Link]

6 Apr 2014

SiA936EDJ2

Vishay Intertechnology Inc. have introduced a dual N-channel TrenchFET power MOSFET in a 2.05 mm square, thermally enhanced PowerPAK SC-70 outline.

The SiA936EDJ device is optimized for use in load and charger switch circuits, DC/DC converters, motor driving H-bridges and battery protection for power management in mobile devices. For healthcare applications it is suitable for non-implantable portable products and also for use with small brushless DC motors in handheld consumer electronics. It offers extremely low on-resistance of 34 milliohms at 4.5 V, 37 milliohms at 3.7 V and 45 milliohms at 2.5 V. The level of on-resistance at 2.5 V is 11.7 % lower than the closest competing 8 V VGS device while providing a higher (G-S) guard band and 15.1 % lower than the closest competing device with a 12 V VGS. A lower RDSON leads to more efficient designs which optimize battery life.

Dual N channel TrenchFET offers lowest RDSON - [Link]

6 Apr 2014

This video reviews the two most common reasons why the output amplitude setting on a function or signal generator doesn’t match what is read on an oscilloscope. This can be due to an incorrect attenuation setting on the scope, but is most commonly due to the fact that the generator is not presented with the load impedance that it is expecting. To correct this most common case, you can either use the correct load impedance, or tell the generator what load you are presenting it with.

Why your Function Generator’s output voltage reading can be wrong - [Link]

 

6 Apr 2014

In this tutorial Dave explains what Operational Amplifiers (OpAmps) are and how they work. The concepts of negative feedback, open loop gain, virtual grounds and opamp action. The comparator, the buffer, the inverting and non-inverting amplifiers, the differential amplifier, and the integrator circuit configurations are also explained. Then a practical breadboard circuit to demonstrate a virtual ground and the effect of voltage rail limitations.

EEVblog #600 – OpAmps Explained - [Link]

6 Apr 2014

TI-2014-0.3-inch-TRP-pico-DLP-chipset

Texas Instruments unveiled a new Tilt & Roll Pixel (TRP) DLP pico chipset. According to TI, this is the smallest (at 0.3″, which is strange because the previous model was 0.2″) and most efficient DLP chip ever. It support HD resolutions (probably 720p) and can be used in pico projectors and wearable displays, augmented reality displays and other applications. [via]

The new Texas Instruments 0.3″ HD Tilt & Roll Pixel (TRP) DLP® Pico™ chipset is TI’s smallest, most power-efficient HD micro-mirror array and can generate 720p displays from compact applications, including tablets, smartphones, accessories, wearable displays, augmented reality displays, interactive surface computing, digital signage and control panels. The chipset delivers significantly higher levels of brightness and power efficiency, allowing developers to create a wide variety of applications and products in smaller form factors than ever before. The chipset’s fast switching speeds of up to thousands of times per second enable the world’s smallest true color RGB engines with 120Hz video performance.

TI’s smallest, most efficient HD pico chipset 0.3″ HD TRP DLP - [Link]

5 Apr 2014

CrowduinoUnoTrH3

Raj @ embedded-lab.com

In this blog post, I am providing you step by step instructions to build a very simple temperature and relative humidity meter for indoor use. All you need to build this project are an Arduino Uno or compatible board, a DHT11 sensor, and a MAX7219 based 8-digit serial 7-segment LED display. The temperature is displayed in degree Celsius and relative humidity in percentage.

Step-by-step guide for making a very simple temperature and humidity meter - [Link]



 
 
 

 

 

 

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