NopHead wrote a review of Elektor 500ppm LCR meter:
I recently bought a 500ppm LCR meter from Elektor because I didn’t have anything for measuring inductors or the ESR (equivalent series resistance) of capacitors, both of which are important for modern electronics, particularly switch mode regulators that have become ubiquitous. It is also more accurate than any of my multimeters and has wider measurement ranges.
Elektor 500ppm LCR meter case tips – [Link]
Researchers at UC Berkeley (California) have developed an Android app that can detect vibrations from earthquakes using the standard sensors integrated into smartphones.
Android app turns smartphones into a seismic network – [Link]
Here is a simple way to measure an unknown inductance by forming a resonance LC circuit and measure it using an oscilloscope. Glen Chenier writes:
One of our technicians recently asked for help determining the value of an SMT inductor. It was unmarked, and was many turns of very fine wire on a ferrite core. The resistance measured 26Ω, which for some reason gave our ancient LCR bridge a conniption, and read 30mH along with a blinking error message. The tech rightfully felt that such a small inductor could not possibly be 30mH.
Measure small LCs with a scope – [Link]
Researchers have developed a smartphone device that measures the cortisol concentration in saliva in order to define your stress levels. The new test is done in under 10 minutes and there is no need to send a salvina sample on a lab. The cost for each measurement is less than 5$ and the smartphone uses its camera and flash to take a picture of the saliva-coated strip and an algorithm converts the image’s pixel density to a cortisol value.
We have developed a method for measuring cortisol in saliva using a smartphone and a disposable test strip. This innovation enables anyone with a smartphone to measure their salivary cortisol level quickly, accurately, and affordably,
Measure Stress Levels Using a Smartphone – [Link]
LG Innotek has released an ultra-thin optical biometric sensor module designed to be used in wearables and smartphones to measure health parameters such as heartbeat, stress indicators and blood oxygen saturation level. The new sensor is more accurate than it’s predecessors achieving ±5 bpm range of error and consumes very little power to operate. At stable heartbeat rate an accuracy of ±2 bpm can be achieved, which is as good as conventional medical instruments. The module is just 1 mm thick and contains a photodiode, five LEDs and an IC.
A biometric sensor for wearables – LG Innotek – [Link]
SolarBoost is an open source smart interface that allows you to build your own powerful and portable solar charger for your phone and other mobile devices. It has two USB ports and can provide 5V @ 2A at each of them and is controlled by a 8-bit 32MHz Microchip PIC microcontroller. It is also equipped with various protection features like soft-start, over-temperature, over-charge, over-discharge, short-circuit and current limiter.
SolarBoost is the first open-hardware and open-source smart interface designed to give you the freedom and flexibility to make your own battery- and solar-powered power bank for charging cellphones, tablets, MP3 players, speakers, GPS navigators, and much more. Use it to also power your DIY electronics projects!
SolarBoost – Make Your Own USB Solar Mobile Charger – [Link]
Here is a quick tear down of an IKEA 400 lm “Ryet” bulb.
Cheapest bulb with full safety listing that I have ever seen. Selling for less than $2.00!
Ryet IKEA LED Bulb teardown – [Link]
Here is an up-down counter based on PIC16F88 and 7-segment display. The counter is using SMD components and features a RS-232 interface.
This is a simple digital counter with a serial rs-232 and a 7 segment display, i started this project to count items on some shelfs, but it can be used for anything, it is also, for the exception of the connectors, completely on SMD components.
UP/DOWN counter with memory using PIC16F88 – [Link]
The circuit diagram presented here is about a negative voltage regulator. It is based on LT1054, which is a switched capacitor voltage converter with regulator from Texas instrument. This device has many advantages over other previously available switched capacitor voltage converters. It provides higher current and has lower voltage losses.
Reno Rossetti & Inyong Kim discuss about the power needs on portable devices and help us choose the right regulator.
A popular power source for portable devices is a single lithium-ion cell with 4.2V at full charge and 2.8V at end of discharge. However, some functions within portable electronics, such as a SIM card and DSP, require 2.8V and 3.3V. These are normally provided by low noise LDOs. The LDOs inputs (VCC) must be at a slightly higher voltage than the highest LDO output. Hence, VCC ends up right in the middle of the lithium-ion battery’s range of operation.
Choose the right step-up/down voltage regulator for portable applications – [Link]
login
