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22 Apr 2014
Cross-section of piezo button assembly

Cross-section of piezo button assembly

by Francesc Casanellas:

This design was done to get a sealed keypad for very wet environments (in my particular case, showers for swimming pools). The keypad needed to be able to detect slight pressure on a stainless steel plate 0.4mm thick. Apart from water protection, the solution offers an esthetical finish, as the user side is absolutely flat, with nothing visible other than the silkscreened print. Another advantage of this type of keypad is that it is vandal-proof. The core of the sensor is a piezoelectric disc, the type normally used as a buzzer. I chose the Murata 7BB-35-3. With 35mm of external diameter, it allows a sensitive area of about 20mm diameter.

Water & vandal-proof keypad uses piezoelectric disc as sensor and buzzer - [Link]

22 Apr 2014


New movement detectors (PIR) represent a Professional solution with up to 30 m range and wide possibilities of assembly.

On the market, there are many movement detectors based on a PIR sensor. For a simple usage, like for example lighting of a garage entry. Probably, it´s not necessary to use a top quality sensor with exactly defined specification and with wide possibilities of adjustment if you´d like to use it for example for a simple lighting of a garage entry. But a for a frequented corridors, security devices, lighting switching, … it´s surely beneficial if having a detector which we can rely on. Detectors from company Finder belong to such category. Finder offers five basic series:

18.01/18.11 – detector with a wide detection angle and a universal assembly with a possibility of an easy selection of a spce to survey. Typ 18.01 is suitable for indoor applications, 18.11 also outdoor.

18.21/18.31 – detector for ceilings with a surface or recessed assembly

18.41 – detector for hotel or office corridors, up to 30x4m range (depending on a height of a ceiling)

18.51 – highly sensitive ceiling type with a square detection pattern (up to 8x8m), suitable for schools, offices and also low activity zones. High sensitivity enables operation in 2 modes – “presence” and “movement”. In this case even a minimum movement, like for example a work on a PC is sufficient to activate the detector. Such a sensitivity can help to prevent for example an unwanted locking of building and activation of alarm, when you already think, that there´s nobody inside (but in fact, somebody is still there :-)).

18.61 – specific product for a wall assembly, 180° angle of survey, detects a half-circle with up to 18m diameter.

All types have elements for adjustment – ambient light sensitivity and a switch-on time of a contact (from a last detection). New types – 18.41, 18.51 and 18.61 also have the third adjusting element – sensitivity of the sensor itself. Thanks to them, it´s possible to adjust a detector to meet requirements of a given application. Logic of switching is an “addition”, i.e. if in time of a switched-on contact occurs another detection, the sensor will prolong the switch-on time for the selected time, i.e. no switch-off of the output contact (neither a short one) will occur. All types are designed for mains applications (96-253VAC) and they have a relay output (10A contact). Contact at types 18.41, 18.51 and 18.61 is also able to switch 400VAC.

Types 18.41, 18.51 and 18.61 are supplied with a rich set of accessories enabling a comfortable and aesthetic mounting as suspended ceiling, recess mounting (for example into a wall) and surface mounting.
Detailed information will provide you the Finder 18.01-31 and Finder 18.41-61 datasheets as well as the Finder 18 flyer (DE) and the attached video.

Detectors Finder will detect you even if you don’t move - [Link]

22 Apr 2014


Dilshan Jayakody writes:

Morse View is an open source software project to convert audible Morse codes to text messages. This application is capable to convert Morse codes from wave files or from the audio line/microphone inputs. Conversion from Morse code to text can perform based on amplitude and frequency decomposition of the input audio stream.
We extensively test this application using Morse code files available at ARRL – W1AW code practice page. During the testing we may be able to use this application to decode 5WPM – 40WPM Morse code inputs.


Audible Morse code to text message converter - [Link]

22 Apr 2014


A smart gauges stepper motor driver app note from Cypress.

This application note shows how to use the PSoC® Programmable System-on-Chip to drive a low-power stepper motor for smart pointer gauges. This application note demonstrates how to perform micro stepping in the stepper motor using PSoC 1.In addition; this application demonstrates using a PC-based utility to control the pointer position in the stepper motor.


App note: Stepper Motor Driver for Smart Gauges - [Link]

22 Apr 2014

H-Bridge Motor Speed Controller Tutorial - [Link]

22 Apr 2014

by mjlorton:

This is a review / buyer’s guide / tutorial on the Rigol DS2000 / DS2072A. As this is my first oscilloscope review I’ve gone into a little more detail for those new to oscilloscopes. I’m trying to use a standard set tests for this review which will carry through to future reviews so comparisons can be made between oscilloscopes.

I will do a side by side review of the Rigol DS2000 vs the Agilent DSOX2000 in the future. In this review I do make comparisons and references to the Agilent 2000 X series.

Review: Rigol DS2000 Oscilloscope - [Link]

21 Apr 2014


hertzgamma @ instructables.com writes:

This instructables will show you how to make an alarm system that will beep a buzzer if you leave the fridge door opened for a long time to remind to you to close the door. All new fridges on the market have this option built in, but some may want to upgrade their old fridges.

Fridge Door Detector Alarm - [Link]

20 Apr 2014


Here is how to make your own usbtinyisp

DIY $5 USBTinyISP - [Link]

20 Apr 2014


RFID keyboard emulators are able to significantly simplify tracking of goods.

“Replacemen” of a keyboard in a form of an RFID module connected to a USB port works very simply – UID of every tag, which will appear in its range will send to a computer – the same way as if we typed it in by a keyboard. SL040A also enables to choose, whether we want the reader to send only data, or also a „CR“ character after every UID (as if an Enter key was hit). It means, that if we already have a software to type in open (for example Excel), the reader itself will fill the cell with data and move the cursor to another cell. SL040A is even able to read data (not only UID) from Mifare tags.

SL040A is also interesting by one feature – on a request from our company SOS Electronic, the producer started to produce also the black version SL040A black.
Detailed information will provide you the SL040A user manual.

SL040A will load it to you directly into a table sheet - [Link]

19 Apr 2014

article-2014apr-offline-switchers-come-tiny-fig2By Ashok Bindra:

When engineers consider offline switchers for systems ranging from telecom and datacom equipment to PCs and industrial supplies, they mainly think of bulky AC/DC front-end solutions in a variety of forms such as bricks, modules, and open-frame. However, there are many applications where offline switchers powered by AC mains are needed in small packages or must occupy a small space on the motherboard. Some examples: USB adapters to power media players, e-readers, and GPS devices; and low-cost, offline LED drivers in lighting applications with high power factor to meet international requirements for total harmonic distortion (THD), EMC, and safety. Offline switchers are also used as standby power supplies in PCs and laptops, as well as in compact chargers for smartphones and other mobile devices. The point is that there are many applications where offline AC/DC switchers are needed in small form-factors.

Offline Switchers Come in Tiny Packages - [Link]





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