Troubleshooting a 32kHz Crystal Oscillator

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How to Actually Make it Oscillate?

Now for an oscillator to work, we need an amplifier with a gain of greater than 1, and a phase shift of 360 degrees to get positive feedback.
First problem – the transistor was saturated, with Vc stuck near 0V. For an oscillator to start noise gets amplified, filtered by the crystal, amplified again etc. I reasoned that if the amplifier wasn’t biased to be linear, the oscillations couldn’t build up. So I reduced the collector resistor to 6.8k, and changed the the base bias resistor to 1.8M to get the collector voltage into a linear region. So now we have Vc=3.2V with a 5V supply.

Troubleshooting a 32kHz Crystal Oscillator – [Link]

Ultra Low-Power (35nA!) Programmable Timer using TI TPL5111

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Ultra Low-Power (35nA!) Programmable Timer using TI TPL5111.

Imagine a system for example that has to work from a small coin cell for 5-10 years.

TPL5111 solves a typical problem in low power wireless systems- things need to be off most of the time, and wake up periodically to transmit.

Ultra Low-Power (35nA!) Programmable Timer using TI TPL5111 – [Link]

Memtype: Open Source Password Keeper

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Memtype is an elegant solution to have your credentials stored everywhere. By Miguel:

Memtype project is a low-cost and open source solution to store your passwords for having them available everywhere in a tiny and portable USB form factor device.

The device is based on the Atmel attiny85 device and uses V-USB software solution to have USB communications and enumerate as a keyboard.

Memtype: Open Source Password Keeper – [Link]

Review: ScanaQuad – a super-small logic analyzer

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Harry Baggen @ elektormagazine.com reviews the ScanaQuad, a new series of tiny 4 channel logic analyzers. The ScanaQuad series consists of four modules (SQ25, SQ50, SQ100 and SQ200), which mainly differ in the sampling rate.

The French company Ikalogic has been making logic analyzers modules since 2010 with a USB port for connection to a laptop or desktop PC. Nothing special, you might say, but late last year they launched a new series of four-channel logic analyzer modules.

Review: ScanaQuad – a super-small logic analyzer – [Link]

Better LEDs with just a trick of the light

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Jan Buiting @ elektormagazine.com discuss about a new technique used by scientist to build better LEDs.

By manipulating the incident light, researchers of the Complex Photonics Group at University of Twente in Enschede, The Netherlands, have turned light propagating in a layer of scattering nanoparticles into a rising diffusion curve.

By transforming the diffusion curve the result is more light energy being held inside an opaque layer which could lead to better yields for solar cells or LEDs. Even in a medium characterized by randomness, like a collection of non-organized particles that all scatter light, the net spreading of light is uniform. This is typical for diffusion.

Better LEDs with just a trick of the light – [Link]

Low cost OBD2 communications on K-line

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RichardvdK @ instructables.com shows us how to use OBD port of your vehicle to push data on a LCD screen. To achieve that he used a 16F886 microcontroller and some common electronics parts.

This is just another OBD2 solution for monitoring the sensors in a vehicle. It supports the K-line OBD2 serial communication between a vehicle and a microcontroller. This K-line communication is also known as ISO 9141-2 or ISO 14230-4 (also known as Keyword Protocol 2000 or KWP). Both ISO’s are almost similar. This solution differs from the rest that is low cost. It is low cost in the way that you don’t need an arduino, raspberry pi or smart phone. Just a microcontroller and LCD display so you can use your smartphone for other purposes.

Low cost OBD2 communications on K-line – [Link]

Control an electrical appliance with your smartphone – WiFi

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Ruben Marc Speybrouck show us how to control a device using your tablet or smartphone. To achieve that he used arduino, blynk and a wemos / ESP8266 board.

In this tutorial we will be making something I call a wifi controlled ac switch. (But iy also works for DC applications that are powered by a wall outlet) Basically we will make a small box that can control any ac electric current in your home, based on commands from your tablet or smartphone. On top of that it can be programmed to react to input from any kind of sensor. Tailored to your needs and limited only by your imagination.

Control an electrical appliance with your smartphone – WiFi – [Link]

Graphene Patterned at Room Temp

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by R. Colin Johnson @ eetimes.com

LAKE WALES Fla.—Graphene is easily grown with chemical vapor deposition (CVD) on copper foil, but a simple way of etching out the necessary circuit patterns and transferring them to a non-metallic substrate has eluded engineers. Now researchers at the University of Illinois (Urbana-Champaign) claim to have a one-step room temperature process for quickly patterning and transferring graphene circuits to flexible substrates using a simple shadow mask.

Graphene Patterned at Room Temp – [Link]

T-baneklokke – A Coundown clock

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Joakim made a coundown clock for his wife and documented the whole process on his blog:

The clock is built using an Arduino, and has a battery powered real time clock to remember the time while powered off.
To make it truly stand alone I added the possibility to set the time and time-to-leave using buttons.
The clock was built into a custom made plexiglass box, and the outside covered with a design printed onto photo paper with a sticky back side. I used my wife’s Cameo vinyl cutter printer to cut the paper – I just love that machine!

T-baneklokke – A Coundown clock – [Link]

DIY electronic RFID Door Lock with Battery Backup

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Elmue build a RFID electronic door lock using PN532 Controller, Vehicle Battery and Teensy 3.2 board.

The advantage of an electronic door lock is that the above security issues do not apply.
It is much better to have a safe door lock which prevents that the thief can enter than to have an alarm system which makes noise when the thief is already in. Until the police arrives he will be gone and probably some precious things will be missing. Secure locks are always better than alarm systems or cameras.

DIY electronic RFID Door Lock with Battery Backup – [Link]

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