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Circuit Skills: Circuit Board Etching

Circuit Skills: Circuit Board Etching

still alive? heartbeat (IR)sensor report Principles: Sense heart rate by using a pair of infrared emitter and reciever, next to each other on top the measuring site on top of the finger. The light bounces from the emitter to the detector across the site. with each heart beat the heart contracts and there is a surge of arterial blood, which momentarily increases arterial blood volume across the measuring site. This results in more light absorption during the surge. if light signals received at the photodetector are looked at 'as a waveform', there should be peaks with each heartbeat and troughs between heartbeats. ( Sensors: Infrared Emitters and Detectors SKU#: SEN-00241 Price: $1.95 Description: Side-looking Infrared Emitters and IR Detectors. datasheet: IR Emitter (Clear)IR Detector (Tinted pink)how it works: Circuit: (simple one without amplifier) Dubug process: The signal is sometimes weak, sometimes strong. pot is used to set the threshold. Code: arduino: if(an1 > an2 && ! int a =0;

Does Google Make Us Stupid? Overview of responses In an online survey of 895 technology stakeholders’ and critics’ expectations of social, political and economic change by 2020, fielded by the Pew Research Center’s Internet & American Life Project and Elon University’s Imagining the Internet Center: » Google won’t make us stupid: 76% of these experts agreed with the statement, “By 2020, people’s use of the Internet has enhanced human intelligence; as people are allowed unprecedented access to more information they become smarter and make better choices. Nicholas Carr was wrong: Google does not make us stupid.” Some of the best answers are in Part 1 of this report. » Reading, writing, and the rendering of knowledge will be improved: 65% agreed with the statement “by 2020 it will be clear that the Internet has enhanced and improved reading, writing and the rendering of knowledge.” » Respondents hope information will flow relatively freely online, though there will be flashpoints over control of the internet.

Build Your Own PCB Chemical Tank Learn how to make your own DIY printed circuit board (PCB) processing tank, step by step. So you need a chemical tank but don’t want to spend many hundreds of dollars on the pre-made PCB tanks commonly found on electronic supplier websites. I used to (notice I say “used to”) have two professional tanks but now use custom build tanks because, when it comes to special requirements and performance, a custom tank will always win, hands down. These tanks are ideal for PCB production and below is a list of the possible tanks you can incorporate into your own workshop: Development tank — For developing photo-resistsEtching tank — For etching off the copperStripping tank — For stripping the resistTin tank — For tinning the copper once cleaned Intial Design Firstly, you can decide what your tank needs so features such as heating, draining and air agitation can be added at almost no extra cost. For those who want to use a plastic box (like Tupperware), you should exercise caution. Design Note: Heater Tap

Networked Arduino Heartbeat sensor + SuperCollider I made a simple heartbeat sensor using an Arduino which sends OSC signals at each heartbeat over a network. I'm using the heartbeat sensor as an awesome prop in my show .. Recotana also wrote the which enabled this project. // cpm_heartbeatEthernet // Version 1.0 October 2009. // Copyright Charles Martin ( // Uses recotana's OSCClass ( // Detect heartbeat using a light reading through skin // On each beat, send an OSC message of the instantaneous // heartrate. #include "Ethernet.h" #include "OSCClass.h" // Pins const int ledPin = 13; const int sensePin = 0; // LED blink variables int ledState = LOW; long ledOnMillis = 0; long ledOnInterval = 50; // Hearbeat detect variables int newHeartReading = 0; int lastHeartReading = 0; int Delta = 0; int recentReadings[8] = {0,0,0,0,0,0,0,0}; int historySize = 8; int recentTotal = 0; int readingsIndex = 0; boolean highChange = false; int totalThreshold = 2; //Debug //Serial.println(recentTotal);

Partner With Us  :  Overview SmartBrief 101 5 Million Subscriptions 180+ Partners / Associations 1,047 Advertisers Total number of summaries in one year - 522,022Total sources used - 7,355 (*2,000 used more than once)Total articles ‘examined’ in a year - 52,445,700 Number of emails sent: Daily - 2.63 millionAnnually - 960 million Lead. At SmartBrief we strive to keep you informed and prepared. Pulse Oximetry Principles of Pulse Oximetry Technology: The principle of pulse oximetry is based on the red and infrared light absorption characteristics of oxygenated and deoxygenated hemoglobin. Oxygenated hemoglobin absorbs more infrared light and allows more red light to pass through. Deoxygenated (or reduced) hemoglobin absorbs more red light and allows more infrared light to pass through. Pulse oximetry uses a light emitter with red and infrared LEDs that shines through a reasonably translucent site with good blood flow. There are two methods of sending light through the measuring site: transmission and reflectance. After the transmitted red (R) and infrared (IR) signals pass through the measuring site and are received at the photodetector, the R/IR ratio is calculated. At the measuring site there are constant light absorbers that are always present.

Broad Museum's scandalous math: A $7.7 million land gift to billionaire from broke Los Angeles City Hall By Tibby Rothman What can $1 a year get a billionaire in Los Angeles these days? click to enlarge Hard bargainer Evidently, a property worth $7.7 million. According to a document obtained by the L.A. Here's the truth, even though it's often unmentioned in media coverage of this touchy issue: The roughly two acres of land is owned by city taxpayers (not by the county, as Los Angeles media have wrongly reported). The $7.7 million valuation was determined by Ronald L. So far Villaraigosa has made no effort to find out if 4 million Los Angeles residents want to fork over a $7.7 million piece of their land to Eli Broad. Moreover, local media including the Los Angeles Times have continued to vastly underplay -- or even leave out entirely -- the fact that the public land to be handed over to Broad will mostly be used for his private foundation's new offices and other non-public space -- not for the much smaller space set aside for the art museum. land owned variously by city and county taxpayers.

Collin's Lab: Infrared heart sensor After checking out a few projects involving IR heart monitors, I decided to have a go at the interface myself. Seen above are the results of my first experimentation with pulse oximetry. Getting the setup up and running satisfactorily required a bit more time and tinkering than I’d expected – especially after reversing a premature mod to my emitter/detector pair. The next version I try will either use a higher output emitter (see Charles Martin’s version) or some amplification hardware (as used in Meng Li’s sensor). Download the m4v file or subscribe in iTunes Related: Heartbeat MIDI controller Collin Cunningham Born, drew a lot, made video, made music on 4-track, then computer, more songwriting, met future wife, went to art school for video major, made websites, toured in a band, worked as web media tech, discovered electronics, taught myself electronics, blogged about DIY electronics, made web videos about electronics and made music for them … and I still do! Related

City of L.A. Smuggles $884 Million From Redevelopment Agency At Surprise Meeting, Ducking State Cuts And Public Scrutiny click to enlarge Update: Do we really want $1 billion and the future of L.A. urban development to remain trapped in the incestual CRA-City Hall family? Update: Turns out they actually transferred all CRA assets and projects, bringing the total city transfer to more like an abstract $1 billion, according to Kaye. Ron Kaye, ex-editor of LA Daily News, spotted the sneak thundercloud yesterday: a mysterious "special meeting" posted to the Community Redevelopment Agency's website, at which CRA commissioners would decide the fate of $884 million. The note was only posted 24 hours before the meeting's start time -- a painful 8:30 a.m. This morning, despite the best efforts of Kaye and erratic city activist John Walsh to thwart them, all six CRA commissioners OKed the $884 million "cooperation agreement" with the City of Los Angeles. How did they get away with this? Yesterday afternoon, in a panic, Kaye urged his loyal readers to barrage L.A. Even the Associated Press caught on:

Transistor LED Flasher - Jose Pino's Projects and Tidbits. If you are familiar with LED flashers using transistor, you may know the basic one uses two transistor, one capacitor and three resistors. There is other kind of oscillator called "flip-flop". As I'm starting to develop some basic circuits, I need a simple LED flasher that can be used in many other applications. After some hours thinking how to create a new simple LED flasher with the minimum components, I decided to use a simple RC. The RC circuit is connected to the base of the NPN transistor (3904) and it gives the signal to the PNP transistor (3906) to turn on the LED. Also, if you want to drive crazy someone or yourself, you can use a speaker to simulate a water drop. The resistor and the capacitor define the frequency. While cleaning "the attic" a few weeks ago, I found this old project.

Grand Avenue Drenched in Misdirection The Luxe Grand Avenue Project, if ever built on a hunk of taxpayer-owned land downtown, will feature a glittery five-star hotel and the curious involvement of the wealthy royal family of Dubai, who control a tiny Gulf oil nation cited by the U.S. State Department for human rights abuses. One thing the public project does not feature, however, is transparency. In a series of moves unusual even for the cloaked deals that precede official rubber-stamping of controversial projects in Los Angeles, key politicians in City Hall and the County Hall of Administration will not — or maybe cannot — answer basic questions about a project that will receive up to $158 million in taxpayer subsidies. The developer, the nationwide Related Companies, says it needs more time because the construction loan market is virtually frozen. The spin from Molina, Perry and other politicos sounds simple — Related just needs several extra months to do the unexpected paperwork. Why?

ELECTRONICS - THE KING OF HOBBIES!: Scrolling text in LED dotmatrix display Multiplexed displays are electronic displays where the entire display is not driven at one time. Instead, sub-units of the display (typically, rows or columns for a dot matrix display or individual characters for a character orientated display, occasionally individual display elements) are multiplexed, that is, driven one at a time, but the electronics and the persistence of vision combine to make the viewer believe the entire display is continuously active. 10x8 LED dot matrix display: Below figure illustrates the construction of a 10x8 LED dot matrix display. In the above figure, the rows are negative and columns are positive. Now, if i continuously shift the column and provide row data corresponding to each column, then i can display the different row data (8 bit) in different columns... . Now, if a set of 8bit data (say 5x8 ) represents a letter, say , ' F ' then we will see letter ' F ' in the display. {*style:<u><b>Circuit explanation: </b></u>*} (example) </i></u>*} {*style:<u><i>