How to Measure LUX With Arduino

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In this tutorial uses the Adafruit TSL2561 sensor to measure LUX with Arduino.

The TSL2561 luminosity sensor is an advanced digital light sensor, ideal for use in a wide range of light situations. Compared to low cost CdS cells, this sensor is more precise, allowing for exact lux calculations and can be configured for different gain/timing ranges to detect light ranges from up to 0.1 – 40,000+ Lux on the fly.

How to Measure LUX With Arduino – [Link]

CIRCUIT WIZARD – Circuit Simulator for begginers

Circuit wizard is one of the good simulators for beginners. Here the tutorial explains how to draw and simulate a circuit in circuit wizard simulator

CIRCUIT WIZARD – Circuit Simulator for beginners – [Link]

How to Set Up WiFi on the Raspberry Pi

circuitbasics.com show us how to setup a Wifi dongle using SSH connection.

Now I’ll explain how to use that SSH connection to setup a WiFi dongle so you can run your Raspberry Pi wirelessly from a remote desktop application. This is a really useful way to set up your Raspberry Pi, because you will be able to access your it over the internet from anywhere in the world. You can use it from your iPhone, iPad, or Laptop from anywhere with an internet connection.

How to Set Up WiFi on the Raspberry Pi – [Link]

Soft Latch Power Switch Circuit

Dаvid Jones through his Youtube channel EEVblog described in detail how to design a cheap soft latch power switch circuit, using one push button switch to toggle your circuit power on and off with the following design requirements:

  1. Zero power when off.
  2. One on/off switch.
  3. Standalone(no MCU).
  4. General components only (Diodes, Transistors, ..ect).
  5. Minimal parts.

First Basic Circuit

SLPW_cir1

A passing transistor is between the input and the output, with another latching transistor.

When we initially power on the circuit, it will be off because the passing transistor is off and so the latching transistor is off (like the egg and chicken). When we turn on the “ON” switch, the passing transistor is on, so the current flows from input to output and therefor the latching transistor is on. To turn it off, press the “OFF” button and the latching transistor is off, and the passing transistor is off.

SLPW_cir1H

First design uses 2 switches and we are looking forward a circuit with one switch only, so let us get a look to the next circuit design.

Second Circuit

SLPW_cir2

When we push the button, the transistor connected to the gate of passing MOSFET will be on, and therefor the passing transistor will be on, on the right side the BJT will be on driving the line down to ground. So next time when you press the the button the transistor connected to gate will be off.

The capacitor connected to base of right side transistor is used to prevent the oscillating on/off while the pressing of the button needs milliseconds and the transistors works much faster.

To see an experiment of the design and to learn more details, check David’s video bellow:

New Alcohol Monitoring System from University of California, San Diego

A new alcohol monitoring system from UCSD consists of a temporary and one-time use tattoo that clings to the human skin and a flexible electronic board that attaches to the tattoo magnetically transfers the results of sensing the blood alcohol concentration via Bluetooth to a smart device paired with it.

The UCSD researchers tried to design the system in a less bulky and less expensive approach. The device uses an electrochemical sensor to measure ethanol molecules emitted through our skin.

tattoo-alcohol

To know more about the results of using this device and how this electrochemical sensor works, read the paper published in ACS Sensors journal.

Via: IEEE SPECTRUM

OpenCellular – An Open Source Wireless Access Platform From Facebook

Promised projects from Google and Facebook may change our world connectivity. We saw previously Loon project from Google and the Internet drone Aquila from Facebook.

Facebook this time is trying to find a general solution to improve the connectivity infrastructure. The project called OpenCellular.

This new project is a software-defined wireless access platform, and this gives it the ability to support everything from 2G to LTE networks.

opncel_ap

The system consists of general-purpose and base-band computing subsystem with integrated power and housekeeping system and a RF with integrated analog front-end. According to the announcement, Facebook plans to open-source the hardware designs to public, along with necessary firmware and control software.

OpenCellular designed to have various power sources: PoE (power-over-ethernet), solar, DC, and external batteries and internal battery (lithium-ion).

opencel_DB

The problem which Facebook try to solve in this new project is to extend network access in both rural and developed communities. The ecosystem cellular networks still constrained, where the infrastructure is very expensive, making it difficult to deploy it everywhere and for smaller organizations or individuals.

opencel_HW

OpenCellular still under lab tests; “we are able to send and receive SMS messages, make voice calls, and use basic data connectivity using 2G implementation on our platform.” according to the announcement.

Via: Facebook

RELATED POSTS

16 Channel Tiny InfraRed Remote Controller – NEC Code

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16 Channel Infra-Red remote controller is built around PIC16F73 Microcontroller from Microchip. The receiver part follows NEC Code Format. Tiny receiver provides 16 latch outputs. All outputs are TTL and can drive Relay board or solid state relay. The circuit uses TSOP1738 Infra-Red receiver module which provides high degree of noise immunity against interfering light source.

For Philips RC5 code check this project: 16 Channel InfraRed remote controller – RC5 Philips Code

Features

  • Supply Remote Transmitter 3V CR2025 Battery
  • Supply Receiver 7V to 12V DC
  • Modulation 38Khz
  • NEC Code Format
  • Operating range up to 10-15 feet
  • 2 Pin Screw Terminals for Supply Input
  • On Board Power LED
  • Onboard VT (Valid Transmission) LED
  • All 16 Channels are Latch Outputs
  • All Outputs TTL Level provided with Header Connector

16 Channel Tiny InfraRed Remote Controller – NEC Code – [Link]

An Atmega library for multiple HD44780 LCDs

LCD_PCF8574_I2C_multiple_library

Davide Gironi has posted an I2C multiple HD44780 AVR Atmega library:

This library implements a driver for HD44780 lcd connected through PCF8574 port expander.
Data is transmitted using only 2 wire over i2c with the PCF8574.
This library can drive up to 8 LCD concurrently.
Lcd driver is based upon Peter Fleury’s lcd driver
HD44780 to i2c library its based upon this library

An Atmega library for multiple HD44780 LCDs – [Link]

DIY PCB inspection microscope

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Saulius made a DIY PCB inspection microscope and wrote a post on his blog about it:

Despite how good microscope you have, stand is still very important part of final assembly. And while there are many commercial ones made of cast iron, they might cost more than a microscope head itself. I decided to make stand from wildly available material laying around – it’s MDF (Medium Density Fiberboard). Advantages – stable over time if not exposed to water, dirt cheap, easy to process.

DIY PCB inspection microscope – [Link]

The DIY diabetes kit that’s keeping us alive

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@ bbc.com:

Frustrated with traditional monitoring and its risks, Mr Samuelson and George have since joined a growing group of T1 sufferers who are building their own solutions to manage their diabetes – even though they come with their own uncertainties.

The DIY diabetes kit that’s keeping us alive – [Link]