Category: Circuits

LM317 to output 3.3 Volts

USB to Serial Cable

I created a simple circuit using the LM317 to output 3.3 volts from a 5V or greater input voltage. Why? Because, a number of modules for the Arduino (or Pinguino) take 3.3 Volts. It’s true, some of the Arduinos do have a 3.3V voltage regulator (and thus a source of 3.3V), however, that might not …

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Emergency Phone Call Alert to an Arduino via an Asterisk PBX

S108T02 Relay Circuit

Recently, I created this simple circuit (and corresponding code) which makes an emergency phone call alert to an Arduino via an Asterisk PBX.  This project was for someone who needed to be alerted (silently) if someone made an emergency phone call on their Asterisk PBX. By the way, the free and open source Asterisk PBX …

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Arduino Weather Station

DHT11

With just a few sensors, one can determine a lot about the weather.                   The BMP085 can be used to sense barometric pressure and temperature and the DHT11 can be used to sense humidity and also temperature. Here is what they look like attached to a mini …

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DIY Dual Relay Circuit

BIY Relay Circuit

It is sometimes very handy to be able to control mains electric via an arduino to turn things like lights on and off.  [warning]BE VERY CAREFUL hooking up any mains electricity. [/warning] I built a dual circuit so that two things can be controlled from one board. Here is the fritzing graphic:   Once built, …

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3 PIN HD44780 LCD

LCD Shift Register Circuit

One of the problems of connecting an HD44780 LCD to an arduino is the number of pins taken up (usually 6). There is an older article here for hooking up an HD44780 LCD to an arduino with only 3 pins.  (Note: There is an alternate link here as the original link may be down.) The …

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DIY Arduino Circuit Board

DIY_Arduino_Circuit_Front

Shown below is one of my DIY Arduino circuits.                 The circuit does not have the FTDI chip built in. The FTDI circuit is only needed for programming and cutting out un-necessary components saves a bit of money. The ICSP connection (6 pins comming out the side) on …

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The BusPirate (a very useful circuit)

BusPirate

A few days ago my son bought me a birthday present. It was a BusPirate from SparkFun. This is what it looks like plugged into a breadboard. The BusPirate is quite a handy circuit. I have used it to flash a BIOS chip using FLASHROM  and also program an AVR ATMEGA 328P with AVRDude. It …

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