aldricnegrier @ instructables.com writes:
The objective of this instructable is to guide your way throw the entire making process of building a BuildersBot machine. An Arduino controlled CNC Router that can also perform 3D printing.
The instructions will cover all areas such as, mechanics, electronics and software.
Arduino Controlled CNC / 3D Printer - [Link]
This Photodiode based Alarm can be used to give a warning alarm when someone passes through a protected area. The circuit is kept standby through a laser beam or IR beam focused on to the Photodiode. When the beam path breaks, alarm will be triggered. The circuit uses a PN Photodiode in the reverse bias mode to detect light intensity. In the presence of Laser / IR rays, the Photodiode conducts and provides base bias to T1.
The NPN transistor T1 conducts and takes the reset pin 4 of IC1 to ground potential. IC1 is wired as an Astable oscillator using the components R3, VR1 and C3. The Astable operates only when its reset pin becomes high. When the Laser / IR beam breaks, current through the Photodiode ceases and T1 turns off. The collector voltage of T1 then goes high and enables IC1. The output pulses from IC1 drives the speaker and alarm tone will be generated.
A simple IR transmitter circuit is given which uses Continuous IR rays. The transmitter can emit IR rays up to 5 meters if the IR LEDs are enclosed in black tubes.
555 Photodiode alarm - [Link]
Brian Dorey made this DIY USB to RS485 adapter, that is available at Github:
We looked for a full-duplex ready-made adapter but all the ones we found are only half duplex devices and as we needed to be able to supply 12 volts via the RJ45 connectors on the slave boards we decided to make our own USB to RS485 full duplex adapter using a USB converter chip from FTDI.
The board uses an FT230X with an RS485 converter chip which outputs to a set of header pins and also an RJ45 socket.
The new adapter board can supply power to the slave devices through the USB port or can be powered from an external supply by removing a power selector jumper. The board also has an on board 120R terminator resistor with selection jumper and LED’s to show serial activity.
USB to RS485 adapter - [Link]
During SOS webinar with 4D Systems you could find out how graphic processor Diablo 16 can make our work easier and shorten time necessary for the development.
Get to know the performance and user-friendly graphic processor Diablo 16 - [Link]
by Nancy Owano @ phys.org:
Sony’s advance in image sensors appears quite natural: the company has developed a set of curved CMOS image sensors based on the curvature of the eye. A report on the sensors in IEEE Spectrum said that, “in a bit of biomimicry,” Sony engineers were able to achieve a set of curved CMOS image sensors using a “bending machine” of their own construction.
Sony inspired by biomimicry develops curved CMOS sensors - [Link]
by Matt Mcgowan @ phys.org:
Engineering researchers at the University of Arkansas have designed integrated circuits that can survive at temperatures greater than 350 degrees Celsius – or roughly 660 degrees Fahrenheit. Their work, funded by the National Science Foundation, will improve the functioning of processors, drivers, controllers and other analog and digital circuits used in power electronics, automobiles and aerospace equipment – all of which must perform at high and often extreme temperatures.
“This ruggedness allows these circuits to be placed in locations where standard silicon-based parts can’t survive,” said Alan Mantooth, Distinguished Professor. “The circuit blocks we designed contributed to superior performance of signal processing, controllers and driver circuitry. We are extremely excited about the results so far.”
Circuits capable of functioning at temperatures greater than 650 degrees fahrenheit - [Link]
lamefreaks @ instructables.com writes:
In this instructable I’m going to show you how to build your own portable audio transmitter. This transmits FM waves so you could easily get the signals on your mobile phone, radios, etc. As the name and the picture indicates it is very small and is approximately the size of a 9v battery clip.
Mini Audio Transmitter - [Link]
Neven Boyanov @ open-electronics.org writes:
The Tinusaur is a small board with a ATtiny85 micro-controller on it. The board has the minimum required components for the micro-controller to work properly. It also has few headers to connect external components and connector for ISP programmer. The board could work with any of those DIP-8 chips such as ATtiny25/ATtiny45/ATtiny85, ATtiny13 as well as their variations.
The goal of the Tinusaur project is to have a simple, cheap and quick-start platform for everyone interested in learning and creating things.
The Tinusaur Project - [Link]
By Jon Gabay:
To do something useful, a microcontroller (MCU) must be connected to other devices. This connection is made through input/output (I/O) pins. More times than not, these days pins are multifunctional and can connect to A/Ds, D/As, linear functions (such as op amps and comparators), voltage references, and more. So for the design engineer, protecting these I/Os against potentially damaging static charges and other similar threats is of high importance.
In establishing proper protection for an MCU, engineers are finding that characteristics they have depended on for years have suddenly become less effective and they are forced to revisit problems of the past. Why? Principally, as a result of market pressure to reduce the cost of their products, semiconductor manufacturers have combined a higher level of integration with continued shrinking of process geometry, making die sizes smaller. As a result, implementing the necessary transient immunity protection to prevent malfunction due to transients on power and signal lines has become increasingly difficult.
Protecting MCU I/O Lines from ESD and Other Transients - [Link]
by brmarcum @ instructables.com:
I hate Christmas tree lights.
Well not really, I just don’t enjoy having to climb under the tree every time I want to plug in or unplug the lights. In the interest of saving my sanity, I decided to build a motion activated switch that can power the lights for me. It has an integrated adjustable timer so they will stay on for as long or as short as I want. Here’s a video showing the final test on the fish tank light.
Motion Activated AC Switch - [Link]